Liquid crystal composition, liquid crystal display element and application thereof

Abstract

Provided is a liquid crystal composition which satisfies the following requirements: a high upper-limit temperature, a low lower-limit temperature, a low viscosity, appropriate optical anisotropy, large dielectric anisotropy, a large dielectric constant in the short-axis direction, a large ratio of the dielectric constant in the short-axis direction to the dielectric anisotropy, a large specific resistance, high stability with respect to light and heat, and a high stability with respect to light and heat. The present invention relates to a liquid crystal composition, a liquid crystal display element, and a use thereof, which have at least one of the characteristics such as high elastic constant, or a suitable balance between at least two of the characteristics. A liquid crystal composition containing, as component A, a specific compound having large optical anisotropy, it is also possible to contain a specific compound having a large dielectric anisotropy as component B, a specific compound having a small viscosity or a high upper limit temperature as component C, or a specific compound having a large dielectric constant in the minor axis direction as component D.

Description

Technical Field

[0001] The present invention relates to a liquid crystal composition, a liquid crystal display element containing the composition, etc. In particular, it relates to a liquid crystal composition with positive dielectric anisotropy, and an AM (active matrix) element containing the composition and having a TN, ECB, OCB, IPS, FFS or FPA mode. Background Art

[0002] In liquid crystal display elements, the operation modes of liquid crystal molecules are classified into 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 other modes. The driving mode of the element is classified into passive matrix (PM) and active matrix (AM). PM is classified into static, multiplex, etc., and AM is classified into thin film transistor (TFT), metal insulator metal (MIM), etc. TFT is classified into amorphous silicon and polycrystalline silicon. The latter are classified into a high temperature type and a low temperature type according to the manufacturing process. The latter are classified into a reflective type using natural light, a transmissive type using backlight, and a semi-transmissive type using both natural light and backlight according to the light source.

[0003] The liquid crystal display element contains a liquid crystal composition having a nematic phase. The composition has appropriate characteristics. By improving the characteristics of the composition, an AM element with good characteristics can be obtained. The relationship between these characteristics is summarized in the following Table 1. The characteristics of the composition are further described based on commercially available AM ​​elements. The temperature range of the nematic phase is related to the temperature range in which the element can be used. The preferred upper limit temperature of the nematic phase is above about 70°C, and the preferred lower limit temperature of the nematic phase is below about -10°C. The viscosity of the composition is related to the response time of the element. In order to display dynamic images with the element, it is preferred that the response time is short. The ideal response time is shorter than 1 millisecond. Therefore, it is preferred that the viscosity of the composition is small. It is further preferred that the viscosity at low temperatures is small. The elastic constant of the composition is related to the contrast of the element. In the element, in order to improve the contrast, it is preferred that the elastic constant of the composition is large.

[0004] Table 1. Properties of the composition and AM device

[0005]

[0006] The optical anisotropy of the composition is associated with the contrast of the element. Depending on the mode of the element, a large optical anisotropy or a small optical anisotropy, that is, an appropriate optical anisotropy, is required. The product (Δn×d) of the optical anisotropy (Δn) 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 operating mode. In elements of modes such as TN, the appropriate value is about 0.45μm. In the case described above, a composition having a large optical anisotropy is preferred for elements with a small cell gap. The large dielectric anisotropy of the composition contributes to the low threshold voltage, small power consumption and large contrast of the element. Therefore, a large dielectric anisotropy is preferred. Dielectric anisotropy is usually frequency-dependent at low temperatures and becomes smaller as the frequency becomes higher. Therefore, at low temperatures, as the driving frequency becomes higher, the movement of the liquid crystal molecules cannot follow the frequency change of the voltage, thereby causing poor display. Therefore, it is preferred that the frequency dependence of the dielectric anisotropy at low temperatures is small. The large specific resistance of the composition contributes to the large voltage holding ratio and large contrast of the element. Therefore, it is preferred to have a composition with a large specific resistance in the initial stage. It is preferred to have a composition with a large specific resistance after long-term use. The stability of the composition to ultraviolet rays and heat is associated with the life of the liquid crystal display element. When these stabilities are high, the life of the element is long. This characteristic is preferred for AM elements used in liquid crystal monitors, liquid crystal televisions, etc.

[0007] A composition having positive dielectric anisotropy is used in an AM device having a TN mode. A composition having negative dielectric anisotropy is used in an AM device having a VA mode. A composition having positive or negative dielectric anisotropy is used in an AM device of a polymer sustained alignment (PSA) type.

[0008] In order to satisfy the required characteristics of liquid crystal display elements as described above, various compounds have been studied, and in recent years, compounds having a sulfur-containing heterocyclic ring have been developed (Patent Documents 1 and 2, etc.).

[0009] Compounds having a thiadiazole ring as such a sulfur-containing heterocyclic ring have been studied in the past, but most of them involve ferroelectric liquid crystals (Patent Document 3, etc.). Regarding uses other than ferroelectric liquid crystals, Patent Document 4 discloses a composition containing a compound having a thiadiazole ring as an example of a composition that can be used in a specific device, namely a vertically aligned splayed nematic liquid crystal display device.

[0010] Thus, so far, only studies related to specific uses have been conducted on compounds having a thiadiazole ring, and studies for use in general-purpose liquid crystal display elements have not been conducted.

[0011] [Prior art literature]

[0012] [Patent Document]

[0013] [Patent Document 1] Japanese Patent Application Publication No. 2020-79385

[0014] [Patent Document 2] Japanese Patent Application Publication No. 2021-165367

[0015] [Patent Document 3] Japanese Patent Application Laid-Open No. 10-213820

[0016] [Patent Document 4] International Publication No. 1997 / 012275 Summary of the invention

[0017] [Problems to be solved by the invention]

[0018] The subject of the present invention is to provide a liquid crystal composition and a liquid crystal display element, wherein the liquid crystal composition fully satisfies at least one of the following characteristics: a high upper limit temperature of the nematic phase, a low lower limit temperature of the nematic phase, a low viscosity, an appropriate optical anisotropy, a large dielectric anisotropy, a large dielectric constant in the short axis direction, a large ratio (ε⊥ / Δε) of the dielectric constant in the short axis direction to the dielectric anisotropy, a large specific resistance, high light stability, high thermal stability, and a large elastic constant, and the liquid crystal display element fully satisfies at least one of the following characteristics: a short response time and a low threshold voltage. Another subject of the present invention is to provide a liquid crystal composition, which has an appropriate balance between at least two of the following characteristics: a high upper limit temperature of the nematic phase, a low lower limit temperature of the nematic phase, a low viscosity, an appropriate optical anisotropy, a large dielectric anisotropy, a large dielectric constant in the short axis direction, a large ratio (ε⊥ / Δε) of the dielectric constant in the short axis direction to the dielectric anisotropy, a large specific resistance, high light stability, high thermal stability, and a large elastic constant. Another object of the present invention is to provide an AM device having characteristics such as a high voltage holding ratio, a high contrast ratio, and a long life.

[0019] [Technical means to solve the problem]

[0020] The present invention relates to a liquid crystal composition and a liquid crystal display element containing the composition. The liquid crystal composition has positive dielectric anisotropy and contains at least one compound selected from the compounds represented by formula (1) as component A.

[0021]

[0022] In formula (1), R 1 and R 2 is hydrogen, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, an alkenyloxy group having 2 to 5 carbon atoms, or an alkyl group having 1 to 5 carbon atoms in which at least one hydrogen is substituted by fluorine or chlorine; Ring A and Ring B are 1,4-cyclohexylene, 1,4-cyclohexenylene, tetrahydropyran-2,5-diyl, 1,4-dioxane, 1,4-phenylene, or 1,4-phenylene in which at least one hydrogen is substituted by fluorine or chlorine; X is sulfur or oxygen; a is 1, 2 or 3; b is 0 or 1; and the sum of a and b is 3 or less.

[0023] [Effects of the Invention]

[0024] The advantages of the present invention are to provide a liquid crystal composition and a liquid crystal display element, wherein the liquid crystal composition fully satisfies at least one of the following characteristics: a high upper limit temperature of the nematic phase, a low lower limit temperature of the nematic phase, a low viscosity, an appropriate optical anisotropy, a large dielectric anisotropy, a large dielectric constant (ε⊥) in the short axis direction, a large ratio (ε⊥ / Δε) of the dielectric constant in the short axis direction to the dielectric anisotropy, a large specific resistance, high light stability, high thermal stability, and a large elastic constant, and the liquid crystal display element fully satisfies at least one of the following characteristics: a short response time and a low threshold voltage. Another advantage of the present invention is to provide a liquid crystal composition, which has an appropriate balance between at least two of the following characteristics: a high upper limit temperature of the nematic phase, a low lower limit temperature of the nematic phase, a low viscosity, an appropriate optical anisotropy, a large dielectric anisotropy, a large dielectric constant in the short axis direction, a large ratio (ε⊥ / Δε) of the dielectric constant in the short axis direction to the dielectric anisotropy, a large specific resistance, high light stability, high thermal stability, and a large elastic constant. Another advantage of the present invention is to provide an AM device having characteristics such as a high voltage holding ratio, a high contrast ratio, and a long life. DETAILED DESCRIPTION

[0025] The usage of terms in this specification is as follows. Sometimes the terms "liquid crystal composition" and "liquid crystal display element" are referred to as "composition" and "element", respectively. "Liquid crystal display element" is a general term for liquid crystal display panels and liquid crystal display modules. "Liquid crystal compound" is a compound having a liquid crystal phase such as a nematic phase and a smectic phase, and a general term for compounds that do not have a liquid crystal phase but are mixed in a composition for the purpose of adjusting the temperature range, viscosity, dielectric anisotropy and other properties of the nematic phase. The compound has a six-membered ring such as 1,4-cyclohexylene or 1,4-phenylene, and its molecule (liquid crystal molecule) is rod-like. "Polymerizable compound" is a compound added for the purpose of generating a polymer in the composition. Liquid crystal compounds having alkenyl groups are not classified as polymerizable compounds in their meaning.

[0026] The liquid crystal composition is prepared by mixing a plurality of liquid crystal compounds. Additives such as optically active compounds or polymerizable compounds are added to the liquid crystal composition as needed. Even when additives are added, the proportion of the liquid crystal compound is expressed by the mass percentage (mass %) based on the mass of the liquid crystal composition excluding the additive. The proportion of the additive is expressed by the mass percentage (mass %) based on the mass of the liquid crystal composition excluding the additive. That is, the proportion of the liquid crystal compound or the additive is calculated based on the total mass of the liquid crystal compound. The proportion of the polymerization initiator and the polymerization inhibitor is expressed based on the mass of the polymerizable compound as an exception.

[0027] Sometimes, the "upper limit temperature of the nematic phase" is referred to as the "upper limit temperature". Sometimes, the "lower limit temperature of the nematic phase" is referred to as the "lower limit temperature". The expression "increasing dielectric anisotropy" means that its value increases positively when the dielectric anisotropy is a composition with positive dielectric anisotropy, and means that its value increases negatively when the dielectric anisotropy is a composition with negative dielectric anisotropy. "High voltage holding ratio" means that the element has a high voltage holding ratio not only at room temperature but also at a temperature close to the upper limit temperature in the initial stage, and that after long-term use, it has a high voltage holding ratio not only at room temperature but also at a temperature close to the upper limit temperature. Sometimes, the characteristics of a composition or element are studied by time-dependent change tests.

[0028]

[0029] The compound (1z) is used as an example for explanation. In formula (1z), the symbols of α and β surrounded by a hexagon correspond to ring α and ring β, respectively, indicating a ring such as a six-membered ring or a condensed ring. When the subscript 'x' is 2, there are two rings α. The two bases represented by the two rings α may be the same or different. The rule applies to any two rings α when the subscript 'x' is greater than 2. The rule also applies to other symbols such as the bonding group Z. The oblique line that crosses one side of the ring β indicates that any hydrogen on the ring β can be replaced by a substituent (-Sp-P). The subscript 'y' indicates the number of substituted substituents. When the subscript 'y' is 0, there is no such substitution. When the subscript 'y' is 2 or more, there are multiple substituents (-Sp-P) on the ring β. In the case, the rule of "may be the same or different" also applies. Furthermore, the rule also applies to the case where the symbol of Ra is used for multiple compounds.

[0030] In formula (1z), for example, "Ra and Rb are alkyl, alkoxy or alkenyl" means that Ra and Rb are independently selected from the group consisting of alkyl, alkoxy and alkenyl. Here, the group represented by Ra and the group represented by Rb may be the same or different.

[0031] At least one compound selected from the compounds represented by formula (1z) is sometimes referred to as “compound (1z)”. “Compound (1z)” refers to one compound, a mixture of two compounds, or a mixture of three or more compounds represented by formula (1z). The same applies to compounds represented by other formulae. The expression “at least one compound selected from the compounds represented by formula (1z) and formula (2z)” refers to at least one compound selected from the group of compound (1z) and compound (2z).

[0032] The expression "at least one 'A'" means that the number of 'A' is arbitrary. The expression "at least one 'A' can be replaced by 'B'" means that when the number of 'A' is one, the position of 'A' is arbitrary, and when the number of 'A' is two or more, their positions can also be selected without restriction. Sometimes the expression "at least one -CH2- can be replaced by -O-" is used. In this case, -CH2-CH2-CH2- can be converted to -O-CH2-O- by replacing non-adjacent -CH2- with -O-. However, there is no case where adjacent -CH2- is replaced by -O-. The reason is that -OO-CH2- (peroxide) is generated in the substitution.

[0033] The alkyl group of the liquid crystal compound is straight-chain or branched, and does not include a cyclic alkyl group. Straight-chain alkyl groups are preferred over branched alkyl groups. These conditions are also the same for terminal groups such as alkoxy and alkenyl. For the stereo configuration related to 1,4-cyclohexylene, the trans configuration is preferred over the cis configuration in order to increase the upper temperature limit. Since 2-fluoro-1,4-phenylene is left-right asymmetric, there are left-facing (L) and right-facing (R).

[0034]

[0035] The same applies to divalent groups such as tetrahydropyran-2,5-diyl and bonding groups such as carbonyloxy (-COO- or -OCO-).

[0036] The present invention includes the following items and the like.

[0037] Item 1. A liquid crystal composition having positive dielectric anisotropy, comprising as component A at least one compound selected from the group consisting of compounds represented by formula (1).

[0038]

[0039] In formula (1), R 1 and R 2 is hydrogen, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, an alkenyloxy group having 2 to 5 carbon atoms, or an alkyl group having 1 to 5 carbon atoms in which at least one hydrogen is substituted by fluorine or chlorine; Ring A and Ring B are 1,4-cyclohexylene, 1,4-cyclohexenylene, tetrahydropyran-2,5-diyl, 1,4-dioxane, 1,4-phenylene, or 1,4-phenylene in which at least one hydrogen is substituted by fluorine or chlorine; X is sulfur or oxygen; a is 1, 2 or 3; b is 0 or 1; and the sum of a and b is 3 or less.

[0040] Item 2. The liquid crystal composition according to Item 1, comprising, as Component A, at least one compound selected from the group consisting of compounds represented by Formula (1-1) to Formula (1-8).

[0041]

[0042] In formula (1-1) to formula (1-8), R 1 and R 2 is hydrogen, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, an alkenyloxy group having 2 to 5 carbon atoms, or an alkyl group having 1 to 5 carbon atoms in which at least one hydrogen atom is replaced by fluorine or chlorine; and Y is hydrogen, fluorine or chlorine.

[0043] Item 3. The liquid crystal composition according to Item 1 or Item 2, wherein the ratio of Component A is in the range of 3% by mass to 30% by mass.

[0044] Item 4. The liquid crystal composition according to any one of Items 1 to 3, comprising, as Component B, at least one compound selected from the group consisting of compounds represented by Formula (2) and Formula (3).

[0045]

[0046] In formula (2), R 3 is an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or an alkenyl group having 2 to 12 carbon atoms; Ring C is 1,4-cyclohexylene, 1,4-phenylene, 2-fluoro-1,4-phenylene, 2,3-difluoro-1,4-phenylene, 2,6-difluoro-1,4-phenylene, pyrimidine-2,5-diyl, 1,3-dioxane-2,5-diyl, or tetrahydropyran-2,5-diyl; 1 is a single bond, ethylene, vinylene, carbonyloxy or difluoromethyleneoxy; X 1 and X 2 is hydrogen or fluorine; Y 1 is fluorine, chlorine, an alkyl group having 1 to 12 carbon atoms in which at least one hydrogen is replaced by fluorine or chlorine, an alkoxy group having 1 to 12 carbon atoms in which at least one hydrogen is replaced by fluorine or chlorine, or an alkenyloxy group having 2 to 12 carbon atoms in which at least one hydrogen is replaced by fluorine or chlorine; c is 1, 2, 3 or 4;

[0047] In formula (3), R 4 is an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or an alkenyl group having 2 to 12 carbon atoms; Ring D is 1,4-cyclohexylene, 1,4-phenylene, 2-fluoro-1,4-phenylene, or 2,6-difluoro-1,4-phenylene; Z 2 is a single bond, carbonyloxy or difluoromethyleneoxy; X 3 and X 4 is hydrogen or fluorine; d is 1, 2, 3 or 4.

[0048] Item 5. The liquid crystal composition according to any one of Items 1 to 4, comprising as component B at least one compound selected from the group consisting of compounds represented by Formula (2-1) to Formula (2-36) and Formula (3-1) to Formula (3-8).

[0049]

[0050]

[0051]

[0052]

[0053]

[0054] In formula (2-1) to formula (2-36), R 3 is an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or an alkenyl group having 2 to 12 carbon atoms;

[0055] In formula (3-1) to formula (3-8), R 4 is an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or an alkenyl group having 2 to 12 carbon atoms; X 3 and X 4 is hydrogen or fluorine.

[0056] Item 6. The liquid crystal composition according to Item 4 or Item 5, wherein the ratio of Component B is in the range of 5 mass % to 50 mass %.

[0057] Item 7. The liquid crystal composition according to any one of Items 1 to 6, comprising, as Component C, at least one compound selected from the group consisting of compounds represented by Formula (4).

[0058]

[0059] In formula (4), R 5 and R 6 is 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, or an alkenyl group having 2 to 12 carbon atoms in which at least one hydrogen atom is replaced by fluorine or chlorine; Ring E and Ring F are 1,4-cyclohexylene, 1,4-phenylene, 2-fluoro-1,4-phenylene or 2,5-difluoro-1,4-phenylene; Z 3 is a single bond, ethylene, vinylene, methyleneoxy or carbonyloxy; e is 1, 2 or 3.

[0060] Item 8. The liquid crystal composition according to any one of Items 1 to 7, comprising, as Component C, at least one compound selected from the group consisting of compounds represented by Formula (4-1) to Formula (4-15).

[0061]

[0062]

[0063] In formula (4-1) to formula (4-15), R 5 and R 6 It is 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 in which at least one hydrogen atom is replaced by fluorine or chlorine, or an alkenyl group having 2 to 12 carbon atoms in which at least one hydrogen atom is replaced by fluorine or chlorine.

[0064] Item 9. The liquid crystal composition according to Item 7 or Item 8, wherein the ratio of Component C is in the range of 10% by mass to 85% by mass.

[0065] Item 10. The liquid crystal composition according to any one of Items 1 to 9, comprising, as Component D, at least one compound selected from the group consisting of compounds represented by Formula (5).

[0066]

[0067] In formula (5), R 7 and R 8 The rings G and J are hydrogen, alkyl having 1 to 12 carbon atoms, alkoxy having 1 to 12 carbon atoms, alkenyl having 2 to 12 carbon atoms, alkenyloxy having 2 to 12 carbon atoms, or alkyl having 1 to 12 carbon atoms in which at least one hydrogen is substituted by fluorine or chlorine; and the rings G and J are 1,4-cyclohexylene, 1,4-cyclohexenylene, tetrahydropyran-2,5-diyl, 1,4-phenylene, 1,4-phenylene in which at least one hydrogen is substituted by fluorine or chlorine, naphthalene-2,6-diyl, naphthalene-2,6-diyl in which at least one hydrogen is substituted by fluorine or chlorine, chromane-2,6-diyl, or chromane-2,6-diyl in which at least one hydrogen is substituted by fluorine or chlorine. orthoalkane-2,6-diyl; Ring I is 2,3-difluoro-1,4-phenylene, 2-chloro-3-fluoro-1,4-phenylene, 2,3-difluoro-5-methyl-1,4-phenylene, 1,8-difluorophenanthrene-2,7-diyl, 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; 4 and Z 5 is a single bond, ethylene, vinylene, methyleneoxy or carbonyloxy; f is 0, 1, 2 or 3, g is 0 or 1; and the sum of f and g is 3 or less.

[0068] Item 11. The liquid crystal composition according to any one of Items 1 to 10, comprising, as Component D, at least one compound selected from the group consisting of compounds represented by Formula (5-1) to Formula (5-36).

[0069]

[0070]

[0071]

[0072]

[0073] In formula (5-1) to formula (5-36), R 7 and R 8 It is hydrogen, 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 alkenyloxy group having 2 to 12 carbon atoms, or an alkyl group having 1 to 12 carbon atoms in which at least one hydrogen atom is substituted by fluorine or chlorine.

[0074] Item 12. The liquid crystal composition according to Item 10 or Item 11, wherein the ratio of Component D is in the range of 1 mass % to 20 mass %.

[0075] Item 13. A liquid crystal display element comprising the liquid crystal composition according to any one of Items 1 to 12.

[0076] Item 14. A liquid crystal display element according to Item 13, wherein the operation mode is TN mode, ECB mode, OCB mode, IPS mode, FFS mode or FPA mode, and the driving method is an active matrix method.

[0077] Item 15. Use of a liquid crystal composition for a liquid crystal display element, wherein the liquid crystal composition is the liquid crystal composition according to any one of Items 1 to 12.

[0078] The present invention also includes the following items. (a) The composition, which contains one compound, two compounds or three or more compounds selected from additives such as optically active compounds, antioxidants, ultraviolet absorbers, matting agents, pigments, defoamers, polymerizable compounds, polymerization initiators, polymerization inhibitors, and polar compounds. (b) An AM element containing the composition. (c) The composition, which also contains a polymerizable compound, and a polymer stabilized alignment (PSA) type AM element containing the composition. (d) A polymer stabilized alignment (PSA) type AM element containing the composition, the polymerizable compound in the composition being polymerized. (e) An element containing the composition and having a PC, TN, STN, ECB, OCB, IPS, VA, FFS or FPA mode. (f) A transmissive element containing the composition. (g) Use of the 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.

[0079] The composition of the present invention is described in the following order. First, the structure of the composition is described. Second, the main characteristics of the component compounds and the main effects of the compounds on the composition or element are described. Third, the combination of the component compounds in the composition, the preferred ratio and the basis thereof are described. Fourth, the preferred form of the component compounds is described. Fifth, the preferred component compounds are shown. Sixth, the additives that can be added to the composition are described. Seventh, the synthesis method of the component compounds is described. Finally, the use of the composition is described.

[0080] First, the structure of the composition is described. The composition contains a plurality of liquid crystal compounds. The composition may also contain additives. The additives are optically active compounds, antioxidants, ultraviolet absorbers, matting agents, pigments, defoaming agents, polymerizable compounds, polymerization initiators, polymerization inhibitors, polar compounds, and the like. From the perspective of liquid crystal compounds, the composition is classified into composition A and composition B. In addition to containing a liquid crystal compound selected from compound (1), compound (2), compound (3), compound (4), and compound (5), composition A may also contain other liquid crystal compounds, additives, and the like. "Other liquid crystal compounds" are liquid crystal compounds different from compound (1), compound (2), compound (3), compound (4), and compound (5). Such compounds are mixed into the composition for the purpose of further adjusting the properties.

[0081] Composition B substantially contains only a liquid crystal compound selected from compound (1), compound (2), compound (3), compound (4) and compound (5). "Substantially" means that although composition B may contain additives, it does not contain other liquid crystal compounds. Compared with composition A, the number of components of composition B is small. From the perspective of cost reduction, composition B is better than composition A. From the perspective of further adjusting the characteristics by mixing other liquid crystal compounds, composition A is better than composition B.

[0082] Second, the main characteristics of the component compounds and the main effects of the compounds on the composition or element are described. The main characteristics of the component compounds are summarized in Table 2. In the symbols in Table 2, L means large or high, M means medium, and S means small or low. The symbols L, M, and S are classifications based on qualitative comparisons between the component compounds, and the symbol 0 (zero) means less than S.

[0083] Table 2. Properties of liquid crystal compounds

[0084] characteristic Compound (1) Compound (2) Compound (3) Compound (4) Compound (5) Upper limit temperature L S~L S~L S~L S~L Viscosity M M~L M~L S~M M~L Optical anisotropy L M~L M~L S~L M~L Dielectric Anisotropy <![CDATA[M~L 1) ]]> M~L L 0 <![CDATA[M~L 1) ]]> Specific resistance L L L L L

[0085] 1) The value of dielectric anisotropy is negative, and the sign indicates the magnitude of the absolute value

[0086] The main effects of the component compounds are as follows. Compound (1) reduces viscosity, increases optical anisotropy, and increases the dielectric constant in the short axis direction. Compound (2) and compound (3) increase dielectric anisotropy. Compound (4) reduces viscosity or increases the maximum temperature. Compound (5) increases the dielectric constant in the short axis direction.

[0087] Third, the combination of the component compounds in the composition, the preferred ratio and the basis thereof are described. Preferred combinations of the component compounds in the composition are compound (1) + compound (2) + compound (4), compound (1) + compound (2) + compound (5), compound (1) + compound (3) + compound (4), compound (1) + compound (3) + compound (5), compound (1) + compound (2) + compound (3) + compound (4), compound (1) + compound (2) + compound (3) + compound (5), compound (1) + compound (2) + compound (4) + compound (5), or compound (1) + compound (2) + compound (3) + compound (4) + compound (5). Particularly preferred combinations are compound (1) + compound (2) + compound (4), compound (1) + compound (2) + compound (3) + compound (4), or compound (1) + compound (2) + compound (4) + compound (5).

[0088] In order to increase the optical anisotropy and the dielectric constant in the minor axis direction, the preferred ratio of compound (1) is about 3% by mass or more, and in order to lower the minimum temperature, the preferred ratio of compound (1) is about 30% by mass or less. A further preferred ratio is in the range of about 3% by mass to about 20% by mass. A particularly preferred ratio is in the range of about 3% by mass to about 15% by mass.

[0089] In order to improve the dielectric anisotropy, the preferred ratio of component B is about 5% by mass or more, and in order to reduce the minimum temperature, the preferred ratio of component B is about 50% by mass or less. A further preferred ratio is in the range of about 10% by mass to about 40% by mass. A particularly preferred ratio is in the range of about 10% by mass to about 30% by mass.

[0090] In order to reduce the viscosity or increase the upper limit temperature, the preferred ratio of compound (4) is about 10% by mass or more, and in order to increase the dielectric anisotropy, the preferred ratio of compound (4) is about 85% by mass or less. A further preferred ratio is in the range of about 20% by mass to about 85% by mass. A particularly preferred ratio is in the range of about 40% by mass to about 80% by mass.

[0091] In order to increase the dielectric constant in the short axis direction, the preferred ratio of compound (5) is about 1% by mass or more, and in order to lower the minimum temperature, the preferred ratio of compound (5) is about 20% by mass or less. A further preferred 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% by mass to about 15% by mass.

[0092] Fourth, preferred forms of the component compounds are described. In formula (1), formula (2), formula (3), formula (4) and formula (5), R 1 and R 2 is hydrogen, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, an alkenyloxy group having 2 to 5 carbon atoms, or an alkyl group having 1 to 5 carbon atoms in which at least one hydrogen atom is replaced by fluorine or chlorine. 1 or R 2 is an alkyl group having 1 to 5 carbon atoms. 3 is an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or an alkenyl group having 2 to 12 carbon atoms. 3 is an alkyl group having 1 to 12 carbon atoms. 4 is an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or an alkenyl group having 2 to 12 carbon atoms. 4 is an alkyl group with 1 to 12 carbon atoms. In order to reduce the viscosity, preferably R 4 is an alkenyl group having 2 to 12 carbon atoms. 5 and R 6 is 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, or an alkenyl group having 2 to 12 carbon atoms in which at least one hydrogen atom is replaced by fluorine or chlorine. 5 or R 6 is an alkyl group with 1 to 12 carbon atoms. In order to reduce the viscosity, preferably R 5 or R 6 is an alkenyl group having 2 to 12 carbon atoms. 7 and R 8 is hydrogen, 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 alkenyloxy group having 2 to 12 carbon atoms, or an alkyl group having 1 to 12 carbon atoms in which at least one hydrogen atom is replaced by fluorine or chlorine. 7 or R 8 is an alkyl group with 1 to 12 carbon atoms. In order to reduce the viscosity, preferably R 7 or R 8 is an alkenyl group having 2 to 12 carbon atoms. In order to increase the dielectric constant in the short axis direction, preferably R 7 or R 8 It is an alkoxy group having 1 to 12 carbon atoms.

[0093] Preferred alkyl groups are methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl or octyl. In order to reduce the viscosity, further preferred alkyl groups are methyl, ethyl, propyl, butyl or pentyl.

[0094] Preferred alkoxy groups are methoxy, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy or heptyloxy. In order to reduce the viscosity, further preferred alkoxy groups are methoxy or ethoxy.

[0095] 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. In order to reduce the viscosity, further preferred alkenyl groups are vinyl, 1-propenyl, 3-butenyl or 3-pentenyl. The preferred stereo configuration of -CH=CH- in these alkenyl groups depends on the position of the double bond. In order to reduce the viscosity, etc., the trans configuration is preferred in alkenyl groups such as 1-propenyl, 1-butenyl, 1-pentenyl, 1-hexenyl, 3-pentenyl and 3-hexenyl. The cis configuration is preferred in alkenyl groups such as 2-butenyl, 2-pentenyl and 2-hexenyl.

[0096] Preferred alkenyloxy groups are vinyloxy, allyloxy, 3-butenyloxy, 3-pentenyloxy or 4-pentenyloxy. In order to reduce the viscosity, further preferred alkenyloxy groups are allyloxy or 3-butenyloxy.

[0097] Preferred examples of the alkyl group in which at least one hydrogen is substituted by fluorine or chlorine are fluoromethyl, 2-fluoroethyl, 3-fluoropropyl, 4-fluorobutyl, 5-fluoropentyl, 6-fluorohexyl, 7-fluoroheptyl or 8-fluorooctyl. In order to improve the dielectric anisotropy, further preferred examples are 2-fluoroethyl, 3-fluoropropyl, 4-fluorobutyl or 5-fluoropentyl.

[0098] Preferred examples of alkenyl groups in which at least one hydrogen is replaced by fluorine or chlorine are 2,2-difluorovinyl, 3,3-difluoro-2-propenyl, 4,4-difluoro-3-butenyl, 5,5-difluoro-4-pentenyl or 6,6-difluoro-5-hexenyl. Further preferred examples are 2,2-difluorovinyl or 4,4-difluoro-3-butenyl in order to reduce the viscosity.

[0099] Ring A and Ring B are 1,4-cyclohexylene, 1,4-cyclohexenylene, tetrahydropyran-2,5-diyl, 1,4-dioxane, 1,4-phenylene, or 1,4-phenylene in which at least one hydrogen is replaced by fluorine or chlorine. In order to reduce the viscosity or to increase the optical anisotropy, the preferred ring A or ring B is 1,4-phenylene, and in order to increase the dielectric constant in the short axis direction, the preferred ring A or ring B is 1,4-phenylene in which at least one hydrogen is replaced by fluorine or chlorine.

[0100] Ring C is 1,4-cyclohexylene, 1,4-phenylene, 2-fluoro-1,4-phenylene, 2,3-difluoro-1,4-phenylene, 2,6-difluoro-1,4-phenylene, pyrimidine-2,5-diyl, 1,3-dioxane-2,5-diyl or tetrahydropyran-2,5-diyl. In order to increase the upper limit temperature, the preferred ring C is 1,4-cyclohexylene, in order to increase the optical anisotropy, the preferred ring C is 1,4-phenylene, in order to increase the dielectric anisotropy, the preferred ring C is 2,6-difluoro-1,4-phenylene. Tetrahydropyran-2,5-diyl is

[0101]

[0102] or

[0103]

[0104] Preferably

[0105]

[0106] Ring D is 1,4-cyclohexylene, 1,4-phenylene, 2-fluoro-1,4-phenylene or 2,6-difluoro-1,4-phenylene. In order to increase the upper limit temperature, the preferred ring D is 1,4-cyclohexylene, in order to increase the optical anisotropy, the preferred ring D is 1,4-phenylene, and in order to increase the dielectric anisotropy, the preferred ring D is 2-fluoro-1,4-phenylene or 2,6-difluoro-1,4-phenylene.

[0107] Ring E and Ring F are 1,4-cyclohexylene, 1,4-phenylene, 2-fluoro-1,4-phenylene or 2,5-difluoro-1,4-phenylene. In order to reduce the viscosity or to increase the upper limit temperature, Ring E or Ring F is preferably 1,4-cyclohexylene, and in order to increase the optical anisotropy or to reduce the lower limit temperature, Ring E or Ring F is preferably 1,4-phenylene or 2-fluoro-1,4-phenylene.

[0108] Ring G and Ring J are 1,4-cyclohexylene, 1,4-cyclohexenylene, tetrahydropyran-2,5-diyl, 1,4-phenylene, 1,4-phenylene in which at least one hydrogen is replaced by fluorine or chlorine, naphthalene-2,6-diyl, naphthalene-2,6-diyl in which at least one hydrogen is replaced by fluorine or chlorine, chromane-2,6-diyl, or chromane-2,6-diyl in which at least one hydrogen is replaced by fluorine or chlorine. Preferred examples of “1,4-phenylene in which at least one hydrogen is replaced by fluorine or chlorine” are 2-fluoro-1,4-phenylene, 2,3-difluoro-1,4-phenylene, or 2-chloro-3-fluoro-1,4-phenylene. In order to reduce the viscosity, the preferred ring G or ring J is 1,4-cyclohexylene, in order to increase the dielectric constant in the short axis direction, the preferred ring G or ring J is tetrahydropyran-2,5-diyl, and in order to increase the optical anisotropy, the preferred ring G or ring J is 1,4-phenylene. The tetrahydropyran-2,5-diyl in the ring G or ring J is

[0109]

[0110] or

[0111]

[0112] Preferably

[0113]

[0114] Ring I is 2,3-difluoro-1,4-phenylene, 2-chloro-3-fluoro-1,4-phenylene, 2,3-difluoro-5-methyl-1,4-phenylene, 1,8-difluoronaphthalene-2,7-diyl, 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 (DBFF2), 4,6-difluorodibenzothiophene-3,7-diyl (DBTF2) or 1,1,6,7-tetrafluoroindan-2,5-diyl (InF4).

[0115]

[0116] In order to reduce the viscosity, the preferred ring I is 2,3-difluoro-1,4-phenylene, and in order to increase the dielectric constant in the short axis direction, the preferred ring I is 4,6-difluorodibenzofuran-3,7-diyl.

[0117] Z 1 Z is a single bond, ethylene, vinylene, carbonyloxy or difluoromethyleneoxy. 1 is a single bond. In order to improve the dielectric anisotropy, the preferred Z 1 Z is difluoromethyleneoxy. 2Z is a single bond, a carbonyl group or a difluoromethylene group. 2 is a single bond. In order to improve the dielectric anisotropy, the preferred Z 2 is carbonyloxy or difluoromethyleneoxy. 3 Z is a single bond, ethylene, vinyl, methyleneoxy or carbonyloxy. 3 Z is a single bond. 4 and Z 5 Z is a single bond, ethylene, vinyl, methyleneoxy or carbonyloxy. 4 or Z 5 For a single bond, in order to reduce the lower limit temperature, the preferred Z 4 or Z 5 In order to improve the dielectric constant in the short axis direction, the preferred Z 4 or Z 5 It is methyleneoxy.

[0118] Divalent groups such as methyleneoxy are asymmetric. In methyleneoxy, -CH2O- is better than -OCH2-. In carbonyloxy, -COO- is better than -OCO-. In difluoromethyleneoxy, -CF2O- is better than -OCF2-.

[0119] X is sulfur or oxygen. In order to increase the maximum temperature and optical anisotropy, X is preferably sulfur.

[0120] Y is hydrogen, fluorine or chlorine. In order to reduce the viscosity, Y is preferably hydrogen, and in order to increase the dielectric constant in the short axis direction, Y is preferably fluorine.

[0121] X 1 and X 2 is hydrogen or fluorine. In order to improve the dielectric anisotropy, the preferred X 1 or X 2 For fluorine.

[0122] X 3 and X 4 In order to reduce the viscosity or to increase the optical anisotropy, X is preferably 3 or X 4 is hydrogen. In order to improve the dielectric anisotropy, the preferred X 3 or X 4 For fluorine.

[0123] Y 1 is fluorine, chlorine, an alkyl group having 1 to 12 carbon atoms in which at least one hydrogen is replaced by fluorine or chlorine, an alkoxy group having 1 to 12 carbon atoms in which at least one hydrogen is replaced by fluorine or chlorine, or an alkenyloxy group having 2 to 12 carbon atoms in which at least one hydrogen is replaced by fluorine or chlorine. In order to improve the dielectric anisotropy, Y is preferably 1is fluorine, an alkyl group having 1 to 12 carbon atoms in which at least one hydrogen is replaced by fluorine or chlorine, or an alkoxy group having 1 to 12 carbon atoms in which at least one hydrogen is replaced by fluorine or chlorine. A preferred example of the alkyl group in which at least one hydrogen is replaced by fluorine or chlorine is trifluoromethyl. A preferred example of the alkoxy group in which at least one hydrogen is replaced by fluorine or chlorine is trifluoromethoxy.

[0124] a is 1, 2 or 3, b is 0 or 1, and the sum of a and b is 3 or less. In order to increase the optical anisotropy and to reduce the viscosity, a or b is preferably 1. c is 1, 2, 3 or 4. In order to reduce the viscosity, c is preferably 2, and in order to increase the upper limit temperature or to increase the dielectric anisotropy, c is preferably 3. d is 1, 2, 3 or 4. In order to reduce the lower limit temperature, d is preferably 1 or 2. e is 1, 2 or 3. In order to reduce the viscosity, e is preferably 1, and in order to increase the upper limit temperature, e is preferably 2 or 3. f is 0, 1, 2 or 3, g is 0 or 1, and the sum of f and g is 3 or less. In order to reduce the viscosity, f is preferably 0 or 1, and in order to increase the upper limit temperature, f is preferably 2. In order to reduce the viscosity, g is preferably 0, and in order to increase the upper limit temperature, g is preferably 1.

[0125] Fifth, preferred component compounds are shown. Preferred compound (1) is compound (1-1) to compound (1-8) described in item 2. Among these compounds, it is preferred that at least one of component A is compound (1-2).

[0126] Preferred compound (2) is compound (2-1) to compound (2-36) described in item 5. Among these compounds, it is preferred that at least one of component B is compound (2-2), compound (2-5), compound (2-8), compound (2-13), compound (2-15), compound (2-16), compound (2-17), compound (2-19), compound (2-23), compound (2-24), compound (2-25), compound (2-27), compound (2-28), compound (2-30) or compound (2-31). It is further preferred that at least one of component B is compound (2-5), compound (2-15), compound (2-17), compound (2-19), compound (2-23), compound (2-24), compound (2-28), compound (2-30) or compound (2-31).

[0127] Preferred compound (3) is compound (3-1) to compound (3-8) described in item 5. Among these compounds, it is preferred that at least one of component B is compound (3-1), compound (3-2), compound (3-3), compound (3-7) or compound (3-8), and it is more preferred that at least one of component B is compound (3-1), compound (3-2) or compound (3-7).

[0128] Preferred compound (4) is compound (4-1) to compound (4-15) described in item 8. Among these compounds, it is preferred that at least one of component C is compound (4-1), compound (4-3), compound (4-7), compound (4-8), compound (4-10) or compound (4-12), and it is further preferred that at least one of component C is compound (4-1), compound (4-7) or compound (4-10).

[0129] Preferred compound (5) is compound (5-1) to compound (5-36) described in item 11. Among these compounds, it is preferred that at least one of component D is compound (5-1), compound (5-2), compound (5-3), compound (5-6), compound (5-8), compound (5-9), compound (5-10), compound (5-14), compound (5-19) or compound (5-36). It is further preferred that at least one of component D is compound (5-8) or compound (5-14).

[0130] Sixth, the additives that can be added to the composition are described. Such additives are optically active compounds, antioxidants, ultraviolet absorbers, matting agents, pigments, defoamers, polymerizable compounds, polymerization initiators, polymerization inhibitors, polar compounds, etc. For the purpose of causing the helical structure of the liquid crystal molecules to give a torsion angle, the optically active compound is added to the composition. Examples of such compounds are compounds (6-1) to compounds (6-5). The preferred ratio of the optically active compound is about 5% by mass or less. A further preferred ratio is in the range of about 0.01% by mass to about 2% by mass.

[0131]

[0132] In order to prevent the decrease in resistivity 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 element has been used for a long time, an antioxidant such as compound (7-1) to compound (7-3) may be further added to the composition.

[0133]

[0134] Compound (7-2) has low volatility and is therefore effective in maintaining a high voltage holding ratio not only at room temperature but also at a temperature close to the upper limit temperature after the element has been used for a long time. In order to obtain the above effect, the preferred ratio of the antioxidant is about 50 ppm or more, and in order not to reduce the upper limit temperature or to increase the lower limit temperature, the preferred ratio of the antioxidant is about 600 ppm or less. A further preferred ratio is in the range of about 100 ppm to about 300 ppm.

[0135] Preferred examples of ultraviolet absorbers are benzophenone derivatives, benzoate derivatives, triazole derivatives, and the like. In addition, light stabilizers such as sterically hindered amines are also preferred. Preferred examples of light stabilizers are compounds (8-1) to (8-16), and the like. In order to obtain the above-mentioned effect, the preferred ratio of these absorbers or stabilizers is about 50 ppm or more, and in order not to lower the upper limit temperature or to not increase the lower limit temperature, the preferred ratio of these absorbers or stabilizers is about 10000 ppm or less. A further preferred ratio is in the range of about 100 ppm to about 10000 ppm.

[0136]

[0137]

[0138] The matting agent is a compound that prevents the decomposition of the liquid crystal compound by accepting the light energy absorbed by the liquid crystal compound and converting it into heat energy. Preferred examples of the matting agent are compounds (9-1) to (9-7) and the like. In order to obtain the above effect, the preferred ratio of these matting agents is about 50 ppm or more, and in order not to increase the lower limit temperature, the preferred ratio of these matting agents is about 20000 ppm or less. A further preferred ratio is in the range of about 100 ppm to about 10000 ppm.

[0139]

[0140] In order to be suitable for the elements of the guest host (GH) mode, dichroic dyes such as azo pigments, anthraquinone pigments, etc. are added to the composition. The preferred ratio of the pigment is in the range of about 0.01 mass % to about 10 mass %. In order to prevent foaming, defoamers such as dimethyl silicone oil and methylphenyl silicone oil are added to the composition. In order to obtain the effect, the preferred ratio of the defoamer is about 1ppm or more, and in order to prevent poor display, the preferred ratio of the defoamer is about 1000ppm or less. Further preferred ratio is in the range of about 1ppm to about 500ppm.

[0141] In order to be suitable for polymer stable orientation (PSA) type elements, polymerizable compounds are used. Preferred examples of such polymerizable compounds are compounds such as acrylates, methacrylates, vinyl compounds, vinyloxy compounds, propenyl ethers, epoxy compounds (oxirane, oxetane), vinyl ketones, etc. Further preferred examples are derivatives of acrylates or methacrylates. Based on the total mass of the polymerizable compound, the preferred ratio is about 10% by mass or more. Further preferred ratio is about 50% by mass or more. Particularly preferred ratio is about 80% by mass or more. The most preferred ratio is 100% by mass.

[0142] When storing the polymerizable compound, a polymerization inhibitor may be added to prevent polymerization. The polymerizable compound is usually added to the composition without removing the polymerization inhibitor. Examples of the polymerization inhibitor include hydroquinone, hydroquinone derivatives such as methyl hydroquinone, 4-tert-butylcatechol, 4-methoxyphenol, phenothiazine, and the like.

[0143] Polar compounds are organic compounds with polarity. Compounds with ionic bonds are not included here. Atoms such as oxygen, sulfur, and nitrogen are negatively charged and tend to have partial negative charges. Carbon and hydrogen are neutral or tend to have partial positive charges. Polarity is caused by the uneven distribution of partial charges between different types of atoms in the compound. For example, polar compounds have at least one partial structure such as -OH, -COOH, -SH, -NH2, >NH, >N-.

[0144] Seventh, the synthesis method of the component compounds is described. These compounds can be synthesized by known methods. Illustrated synthesis method. The synthesis example of compound (1) is described in Example 1. Compound (2-19) is synthesized by the method described in Japanese Patent Laid-Open No. 10-251186. Compound (3-7) is synthesized by the method described in Japanese Patent Laid-Open No. 10-114733. Compound (4-1) is synthesized by the method described in Japanese Patent Laid-Open No. 9-77692. Compound (5-1) is synthesized by the method described in Japanese Patent Table No. 2-503441. Antioxidants are commercially available. Compound (7-1) can be obtained from Sigma-Aldrich Corporation. Compound (7-2) and the like are synthesized by the method described in the specification of U.S. Patent No. 3,660,505.

[0145] Compounds for which no synthesis method is described can be synthesized by methods described in the following books: Organic Syntheses (John Wiley & Sons, Inc.), Organic Reactions (John Wiley & Sons, Inc.), Comprehensive Organic Synthesis (Pergamon Press), New Experimental Chemistry Lectures (Maruzen), etc. The composition is prepared by a known method from the compound obtained in the above manner. For example, the component compounds are mixed and then dissolved in each other by heating.

[0146] Finally, the use of the composition is described. The composition mainly has a lower limit temperature of about -10°C or less, an upper limit temperature of about 70°C or more, and an optical anisotropy in the 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 can also be prepared by controlling the ratio of the component compounds or by mixing other liquid crystal compounds. A composition having an optical anisotropy in the range of about 0.10 to about 0.30 can also be prepared by repeated experiments. The element 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.

[0147] The composition can be used for AM elements. Furthermore, it 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, and FPA. It is particularly preferably used for AM elements having TN, OCB, IPS mode, or FFS mode. In AM elements having IPS mode or FFS mode, when no voltage is applied, the arrangement of liquid crystal molecules can be parallel to the glass substrate, or can also be vertical. These elements can be reflective, transmissive, or semi-transmissive. It is preferably used for transmissive elements. It can also be used for amorphous silicon-TFT elements or polycrystalline silicon-TFT elements. The composition can also be used for nematic curvilinear aligned phase (NCAP) type elements made by microencapsulation, or polymer dispersed (PD) type elements in which a three-dimensional network polymer is formed in the composition.

[0148] [Example]

[0149] The present invention is further described in detail by examples. The present invention is not limited by these examples. The present invention includes a mixture of the composition of Example 1 and the composition of Example 2. The present invention also includes a mixture of at least two of the compositions of the examples. The synthesized compound is identified by methods such as nuclear magnetic resonance (NMR) analysis. The properties of the compounds, compositions and components are measured by the methods described below.

[0150] NMR analysis: DRX-500 manufactured by Bruker BioSpin was used for the measurement. 1 In the H-NMR measurement, the sample is dissolved in a deuterated solvent such as CDCl3, and the measurement is performed at room temperature, 500 MHz, and 16 accumulation times. Tetramethylsilane is used as an internal standard. 19 In the determination of F-NMR, CFCl3 was used as an internal standard and the cumulative number of measurements was 24. In the description of the nuclear magnetic resonance spectrum, s refers to a singlet, d refers to a doublet, t refers to a triplet, q refers to a quartet, quin refers to a quintet, sex refers to a sextet, m refers to a multiplet, and br refers to a broad peak.

[0151] Gas chromatography analysis: A GC-14B gas chromatograph manufactured by Shimadzu Corporation was used for the measurement. The carrier gas was helium (2 mL / min). The sample vaporization chamber was set to 280°C, and the detector (flame ionization detector (FID)) was set to 300°C. A capillary column DB-1 (length 30 m, inner diameter 0.32 mm, film thickness 0.25 μm; the stationary liquid phase was dimethylpolysiloxane; non-polar) manufactured by Agilent Technologies Inc. was used for separation of the component compounds. The column was kept at 200°C for 2 minutes and then heated to 280°C at a rate of 5°C / min. After the sample was prepared as an acetone solution (0.1 mass %), 1 μL of it was injected into the sample vaporization chamber. The recorder was a C-R5A chromatograph assembly (Chromatopac) manufactured by Shimadzu Corporation or its equivalent. The obtained gas chromatogram shows the retention time and peak area of ​​the peak corresponding to the component compounds.

[0152] The solvent used to dilute the sample can use chloroform, hexane, etc. In order to separate the component compounds, the following capillary columns can be used. HP-1 (length 30m, inner diameter 0.32mm, film thickness 0.25μm) manufactured by Agilent Technologies Inc., Rtx-1 (length 30m, inner diameter 0.32mm, film thickness 0.25μm) manufactured by Restek Corporation, BP-1 (length 30m, inner diameter 0.32mm, film thickness 0.25μm) manufactured by SGE International Pty. Ltd., Australia. For the purpose of preventing the overlap of compound peaks, the capillary column CBP1-M50-025 (length 50m, inner diameter 0.25mm, film thickness 0.25μm) manufactured by Shimadzu Corporation can be used.

[0153] The ratio of the liquid crystal compound contained in the composition can be calculated using the method described below. The mixture of liquid crystal compounds is analyzed using gas chromatography (FID). The area ratio of the peaks in the gas chromatogram is equivalent to the ratio of the liquid crystal compounds. When using the capillary column described above, the correction factor of each liquid crystal compound can be regarded as 1. Therefore, the ratio (mass %) of the liquid crystal compound can be calculated based on the area ratio of the peak.

[0154] Determination of sample: When measuring the properties of a composition or an element, the composition is directly used as a sample. When measuring the properties of a compound, a sample for measurement is prepared by mixing the compound (15% by mass) in a mother liquid crystal (85% by mass). Based on the values ​​obtained by the measurement, the characteristic values ​​of the compound are calculated using the extrapolation method. (Extrapolation value) = {(measured value of the sample) - 0.85 × (measured value of the mother liquid crystal)} / 0.15. When a smectic phase (or crystal) precipitates at 25°C under the ratio, the ratio of the compound to the mother liquid crystal is changed in the order of 10% by mass: 90% by mass, 5% by mass: 95% by mass, and 1% by mass: 99% by mass. The values ​​of the upper limit temperature, optical anisotropy, viscosity, and dielectric anisotropy associated with the compound are obtained by the extrapolation method.

[0155] The following mother liquid crystals were used. The ratio of the component compounds is expressed by mass %.

[0156]

[0157] Measurement method: The characteristics were measured using the following methods. Most of these methods are methods described in the JEITA standard (JEITA ED-2521B) reviewed and formulated by the Japan Electronics and Information Technology Industries Association (JEITA) or modified methods thereof. The TN element used for the measurement does not have a thin film transistor (TFT) mounted on it.

[0158] (1) Upper limit temperature of nematic phase (NI; °C): Place the sample on a hot plate of a melting point measuring device equipped with a polarizing microscope and heat it at a rate of 1 °C / min. Measure the temperature at which a portion of the sample changes from the nematic phase to an isotropic liquid. The upper limit temperature of the nematic phase is sometimes referred to as simply the "upper limit temperature".

[0159] (2) The lower limit temperature of the nematic phase (T C ; ℃): Place a sample with a nematic phase in a glass bottle and store it in a freezer at 0℃, -10℃, -20℃, -30℃ and -40℃ for 10 days, and then observe the liquid crystal phase. For example, if the sample remains in the nematic phase at -20℃ and changes to a crystalline or smectic phase at -30℃, the T C It is described as <-20° C. The lower limit temperature of the nematic phase may be simply referred to as “lower limit temperature”.

[0160] (3) Viscosity (bulk viscosity; η; measured at 20°C; mPa·s): An E-type rotational viscometer manufactured by Tokyo Keiki Co., Ltd. was used for measurement.

[0161] (4) Viscosity (rotational viscosity; γ1; measured at 25°C; mPa·s): Measured according to the method described in M. Imai et al., "Molecular Crystals and Liquid Crystals", Vol. 259, 37 (1995). A sample was placed in a TN device with a twist angle of 0° and a distance (cell gap) between two glass substrates of 5 μm. A voltage was applied to the device in steps of 0.5 V in the range of 16 V to 19.5 V. After no voltage was applied for 0.2 seconds, voltage was repeatedly applied under the conditions of applying only one rectangular wave (rectangular pulse; 0.2 seconds) and not applying (2 seconds). The peak current and peak time of the transient current generated by the application were measured. The rotational viscosity value was obtained based on these measured values ​​and the calculation formula (10) described on page 40 of the paper by M. Imai et al. The value of dielectric anisotropy required for the above calculation is obtained by the method described below using the element for measuring the above rotational viscosity.

[0162] (5) Optical anisotropy (refractive index anisotropy; Δn; measured at 25°C): Measured using light of 589 nm wavelength using an Abbe refractometer with a polarizing plate mounted on the eyepiece. After rubbing the surface of the main prism in one direction, drop the sample onto the main 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 polarization is perpendicular to the direction of rubbing. The value of optical anisotropy is calculated using the formula Δn = n∥ - n⊥.

[0163] (6) Dielectric anisotropy (Δε; measured at 25°C): A sample was placed in a TN device in which the distance between two glass substrates (cell gap) was 9 μm and the twist angle was 80 degrees. A sine wave (10 V, 1 kHz) was applied to the device, and after 2 seconds, the dielectric constant (ε∥) in the long axis direction of the liquid crystal molecules was measured. A sine wave (0.5 V, 1 kHz) was applied to the device, and after 2 seconds, the dielectric constant (ε⊥) in the short axis direction of the liquid crystal molecules was measured. The value of dielectric anisotropy is calculated based on the formula Δε=ε∥-ε⊥.

[0164] (7-1) Threshold voltage (Vth(25); measured at 25°C; V): A Liquid Crystal Display (LCD) 5200 type luminance meter manufactured by Otsuka Electronics Co., Ltd. was used for the measurement. The light source was a halogen lamp. A sample was placed in an FFS element in which the distance between two glass substrates (cell gap) was 3.2 (μm). The voltage applied to the element (32Hz, rectangular wave) was increased stepwise from 0V in units of 0.01V to 10V. At this time, light was irradiated to the element from a vertical direction, and the amount of light passing through the element was measured. A voltage-transmittance curve was prepared in which the transmittance was 100% when the light amount was maximum and the transmittance was 0% when the light amount was minimum. The threshold voltage is represented by the voltage when the transmittance becomes 90%.

[0165] (7-2) Threshold voltage (Vth(-30); measured at -30°C; V): Same as (7-1) except that the measurement was performed at -30°C.

[0166] (8) Voltage holding ratio (VHR-9; measured at 25°C; %): The TN element used for the measurement has a polyimide orientation film, and the interval between the two glass substrates (cell gap) is 5 μm. The element is sealed with an adhesive that is cured by ultraviolet light after the sample is placed. A pulse voltage (1 V, 60 microseconds) is applied to the TN element for charging. The decaying voltage is measured over a period of 1000 milliseconds using a high-speed voltmeter, and the area A between the voltage curve per unit period and the horizontal axis is calculated. Area B is the area when there is no decay. The voltage holding ratio is expressed as a percentage of area A relative to area B.

[0167] (9) Voltage holding ratio (VHR-10; measured at 60° C.; %): The voltage holding ratio was measured by the same procedure as described above, except that the measurement was conducted at 60° C. instead of 25° C. The obtained value is expressed as VHR-10.

[0168] (10) Voltage holding ratio (VHR-11; measured at 60°C; %): After irradiation with ultraviolet light, the voltage holding ratio was measured to evaluate the stability against ultraviolet light. The TN element used for the measurement had a polyimide alignment film and a cell gap of 5 μm. The sample was injected into the element and irradiated with 5 mW / cm 2 The light source was a black light, F40T10 / BL (peak wavelength 369 nm), manufactured by Iwasaki Eyegraphics Co., Ltd. The distance between the element and the light source was 5 mm. In the measurement of VHR-11, the decaying voltage was measured over a period of 1000 milliseconds. A composition having a large VHR-11 has a great stability against ultraviolet rays.

[0169] (11) Voltage holding ratio (VHR-12; measured at 60°C; %): After heating the TN device injected with the sample in a constant temperature bath at 120°C for 20 hours, the voltage holding ratio was measured to evaluate the thermal stability. In the measurement of VHR-12, the decaying voltage was measured over a period of 1000 milliseconds. A composition having a large VHR-12 has a high thermal stability.

[0170] (12) Voltage holding ratio (VHR-13; measured at 60°C; %): After heating the TN device injected with the sample in a constant temperature bath at 100°C for three weeks, the voltage holding ratio was measured to evaluate the thermal stability. In the measurement of VHR-13, the decaying voltage was measured over a period of 1000 milliseconds. A composition having a large VHR-13 has a high thermal stability.

[0171] (13) Voltage holding ratio (VHR-14; measured at 60°C; %): After the TN device injected with the sample was left to stand on a backlight for two weeks, the voltage holding ratio was measured to evaluate the stability to the backlight. In the measurement of VHR-14, the decaying voltage was measured over a period of 1000 milliseconds. A composition having a large VHR-14 has a high stability to the backlight.

[0172] (14-1) Response time (τ(25); measured at 25°C; ms): An LCD5200 luminance meter manufactured by Otsuka Electronics Co., Ltd. was used for the measurement. The light source was a halogen lamp. The low-pass filter was set to 5kHz. A sample was placed in an FFS element in which the distance between two glass substrates (cell gap) was 3.2μm. A rectangular wave (60Hz, 5V, 0.5 seconds) was applied to the element. At this time, light was irradiated to the element from a vertical direction, and the amount of light passing through the element was measured. When the amount of light was maximum, the transmittance was considered to be 100%, and when the amount of light was minimum, the transmittance was considered to be 0%. The rise time (τr: risetime; milliseconds) is the time required for the transmittance to change from 90% to 10%. The fall time (τf: fall time; milliseconds) is the time required for the transmittance to change from 10% to 90%. The response time is represented by the sum of the rise time and the fall time calculated in the above manner.

[0173] (14-2) Response time (τ(-30); measured at -30°C; ms): Same as (14-1), except that the measurement was performed at -30°C and the rectangular wave application conditions were changed (60 Hz, 5 V, 15 seconds).

[0174] (15) Elastic constant (K; measured at 25°C; pN): The measurement was performed using an HP4284A LCR meter manufactured by Yokogawa Hewlett-Packard Co., Ltd. A sample was placed in a horizontally oriented element in which the interval between two glass substrates (cell gap) was 20 μm. A charge of 0 volts to 20 volts was applied to the element, and the electrostatic capacitance and applied voltage were measured. The measured electrostatic capacitance (C) and applied voltage (V) values ​​were fitted using equations (2.98) and (2.101) on page 75 of the Liquid Crystal Device Handbook (Nikkan Kogyo Shimbun), and the values ​​of K11 and K33 were obtained according to equation (2.99). Next, the previously determined values ​​of K11 and K33 were used in equation (3.18) on page 171 of the Liquid Crystal Device Handbook (Nikkan Kogyo Shimbun) to calculate K22. The elastic constant is represented by the average value of K11, K22, and K33 obtained in the above manner.

[0175] (16) Specific resistance (ρ; measured at 25°C; Ωcm): 1.0 mL of a sample is injected into a container equipped with electrodes. A DC voltage (10 V) is applied to the container, and the DC current is measured after 10 seconds. The specific resistance is calculated according to the following formula: (Specific resistance) = {(voltage) × (capacitance of container)} / {(DC current) × (dielectric constant of vacuum)}.

[0176] (17) Pitch (P; measured at room temperature; μm): The pitch is measured using the wedge method. (See page 196 of "Liquid Crystal Handbook" (published in 2000, Maruzen)). The sample is injected into the wedge unit and allowed to stand at room temperature for 2 hours. The spacing (d2-d1) of the disclination lines is then observed using a polarizing microscope (Nikon Co., Ltd., trade name MM40 / 60 series). The pitch (P) is calculated using the following formula in which the angle of the wedge unit is expressed as θ. P = 2×(d2-d1)×tanθ.

[0177] (18) Dielectric constant in the short axis direction (ε⊥; measured at 25°C): A sample was placed in a TN device with a distance between two glass substrates (cell gap) of 9 μm and a twist angle of 80 degrees. A sine wave (0.5 V, 1 kHz) was applied to the device, and after 2 seconds, the dielectric constant (ε⊥) in the short axis direction of the liquid crystal molecules was measured.

[0178] (19) Frequency dependence of dielectric anisotropy (F10; measured at -20°C): A sample is placed in a TN device in which the distance between two glass substrates (cell gap) is 9 μm and the twist angle is 80 degrees. A sine wave (0.5 V, 100 Hz, 200 Hz, 500 Hz, 800 Hz, 1 kHz, 2 kHz, 5 kHz, 8 kHz, 10 kHz, 20 kHz, 50 kHz, 80 kHz, 100 kHz) is applied to the device, and after 2 seconds, the dielectric constant (ε⊥) in the short axis direction of the liquid crystal molecules is measured. The frequency at which the dielectric anisotropy decreases by 10% relative to the dielectric anisotropy at 100 Hz is defined as F10. The larger the F10, the smaller the frequency dependence.

[0179] Compound (1-2-1) was synthesized by the following route.

[0180]

[0181] First step: Synthesis of compound (b)

[0182] Compound (a) (150 g, 0.91 mol) was suspended in thionyl chloride (100 mL), and dimethylformamide (DMF) (5 mL) was added and heated under reflux for 3 hours. After cooling, thionyl chloride was removed under reduced pressure to obtain compound (b) (164 g, 0.90 mol, yield 98.0%).

[0183] Second step: Synthesis of compound (d)

[0184] Compound (c) (100 g, 0.61 mol) was dissolved in tetrahydrofuran (THF) (100 mL), hydrazine monohydrate (100 mL) was added and heated under reflux for 7 hours. After cooling, the mixture was put into water (500 mL) and the precipitated solid was separated by filtration. The obtained solid was recrystallized from ethanol (150 mL) to obtain compound (d) (52.4 g, 0.35 mol, yield 57.3%).

[0185] Step 3: Synthesis of Compound (e)

[0186] Compound (d) (120.0 g, 0.80 mol) and compound (b) (131.4 g, 0.72 mol) were suspended in THF (320 mL), pyridine (120 mL) was added and heated under reflux for 5 hours. After cooling, the mixture was put into water (4 L) and the precipitated solid was separated by filtration. The obtained solid was recrystallized from ethanol (5 L) to obtain compound (e) (159 g, 0.54 mol, yield 74.6%).

[0187] Fourth step: Synthesis of compound (1-2-1)

[0188] Compound (e) (74.0 g, 0.25 mol) and Lawesson's reagent (100 g, 0.25 mol) were suspended in THF (500 mL) and heated under reflux for 8 hours. After cooling, the mixture was put into water (500 mL), toluene (500 mL) was added and the organic layer was separated, and magnesium sulfate and sodium sulfate were added as drying agents. Furthermore, the solid matter was filtered and separated, and the filtrate was concentrated under reduced pressure. The obtained solid was purified by column chromatography (toluene) and recrystallized from ethanol (80 mL) to obtain compound (1-2-1) (26.5 g, 0.09 mol, yield 36.0%).

[0189] 1 H-NMR(CDCl3)δ7.90(t,J=8.5Hz,4H),7.29(dd,J=8.5Hz,2.0Hz,4H),2.65(t,J=7.5Hz,2H),2.42(s,3H),1.68(sex,2H),0.97(t,J=7.2Hz,3H).

[0190] Upper limit temperature (NI) = 162.6°C; dielectric anisotropy (Δε) = -5.67; optical anisotropy (Δn) = 0.320; viscosity (η) = 45.1 mPa·s.

[0191] The following is an example of a composition. The component compounds are represented by symbols based on the definitions in Table 3 below. In Table 3, the stereo configuration associated with 1,4-cyclohexylene is a trans configuration. The number in the bracket after the symbolized compound indicates the chemical formula to which the compound belongs. The symbol (-) refers to other liquid crystal compounds. The ratio (percentage) of liquid crystal compounds is the mass percentage (mass %) based on the mass of the liquid crystal composition excluding additives. Finally, the characteristic values ​​of the composition are summarized.

[0192] Table 3. Notation of compounds using symbols

[0193] R-(A1)-Z1-·····-Z n -(A n )-R'

[0194]

[0195] A composition free of compound (1) was prepared.

[0196] [Comparative Example 1]

[0197]

[0198] NI=100.2°C; Tc<-10°C; Δn=0.111; Δε=2.9; ε⊥ / Δε=1.3; γ1=74.7 mPa·s. Based on the composition of Comparative Example 1, a composition containing compound (1) and having the same NI was prepared.

[0199] [Example 1]

[0200]

[0201] NI=101.4℃; Tc<-40℃; Δn=0.111; Δε=2.9; ε⊥ / Δε=1.3; γ1=67.9mPa·s.[Example 2]

[0202]

[0203]

[0204] NI = 100.0°C; Tc < -40°C; Δn = 0.111; Δε = 3.3; γ1 = 69.0 mPa·s. [Example 3]

[0205]

[0206] NI = 98.9 ° C; Tc < -40 ° C; Δn = 0.110; Δε = 3.3; γ1 = 56.8 mPa·s. [Example 4]

[0207]

[0208]

[0209] NI = 81.0°C; Tc < -20°C; Δn = 0.140; Δε = 3.2; γ1 = 42.3 mPa·s. [Example 5]

[0210]

[0211] NI = 75.1°C; Tc < -20°C; Δn = 0.151; Δε = 3.7; γ1 = 42.1 mPa·s. [Example 6]

[0212]

[0213] NI = 76.5°C; Tc < -20°C; Δn = 0.151; Δε = 2.9; γ1 = 38.4 mPa·s. [Example 7]

[0214]

[0215] NI = 100.8°C; Tc < -20°C; Δn = 0.103; Δε = 2.4; γ1 = 56.2 mPa·s. [Example 8]

[0216]

[0217] NI = 94.3 ° C; Tc < -20 ° C; Δn = 0.122; Δε = 2.4; γ1 = 51.4 mPa·s. [Example 9]

[0218]

[0219] NI = 106.6°C; Tc < -30°C; Δn = 0.104; Δε = 2.5; γ1 = 68.5 mPa·s. [Example 10]

[0220]

[0221]

[0222] NI=100.2℃; Tc<-30℃; Δn=0.106; Δε=3.0; γ1=60.3mPa·s.

[0223] The rotational viscosity of the composition of Comparative Example 1 was 74.7 mPa·s, and the nematic phase could not be maintained at -20°C and crystallized. On the other hand, the rotational viscosity of the composition of Example 1 was 67.9 mPa·s, and the crystallization did not occur at least at -40°C. Therefore, it was concluded that the liquid crystal composition of the present invention had excellent properties.

[0224] [Industrial Applicability]

[0225] 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 having positive dielectric anisotropy, comprising at least one compound selected from the compounds represented by formula (1) as component A; In formula (1), R 1 and R 2 is hydrogen, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, an alkenyloxy group having 2 to 5 carbon atoms, or an alkyl group having 1 to 5 carbon atoms in which at least one hydrogen is substituted by fluorine or chlorine; Ring A and Ring B are 1,4-cyclohexylene, 1,4-cyclohexenylene, tetrahydropyran-2,5-diyl, 1,4-dioxane, 1,4-phenylene, or 1,4-phenylene in which at least one hydrogen is substituted by fluorine or chlorine; X is sulfur or oxygen; a is 1, 2 or 3; b is 0 or 1; and the sum of a and b is 3 or less.

2. The liquid crystal composition according to claim 1, comprising at least one compound selected from the group consisting of compounds represented by formula (1-1) to formula (1-8) as component A; In formula (1-1) to formula (1-8), R 1 and R 2 is hydrogen, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, an alkenyloxy group having 2 to 5 carbon atoms, or an alkyl group having 1 to 5 carbon atoms in which at least one hydrogen atom is replaced by fluorine or chlorine; and Y is hydrogen, fluorine or chlorine.

3. The liquid crystal composition according to claim 1 or 2, wherein: The ratio of component A is in the range of 3 mass % to 30 mass %.

4. The liquid crystal composition according to claim 1, comprising at least one compound selected from the group consisting of compounds represented by formula (2) and formula (3) as component B; In formula (2), R 3 is an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or an alkenyl group having 2 to 12 carbon atoms; Ring C is 1,4-cyclohexylene, 1,4-phenylene, 2-fluoro-1,4-phenylene, 2,3-difluoro-1,4-phenylene, 2,6-difluoro-1,4-phenylene, pyrimidine-2,5-diyl, 1,3-dioxane-2,5-diyl, or tetrahydropyran-2,5-diyl; 1 is a single bond, ethylene, vinylene, carbonyloxy or difluoromethyleneoxy; X 1 and X 2 is hydrogen or fluorine; Y 1 is fluorine, chlorine, an alkyl group having 1 to 12 carbon atoms in which at least one hydrogen is replaced by fluorine or chlorine, an alkoxy group having 1 to 12 carbon atoms in which at least one hydrogen is replaced by fluorine or chlorine, or an alkenyloxy group having 2 to 12 carbon atoms in which at least one hydrogen is replaced by fluorine or chlorine; c is 1, 2, 3 or 4; In formula (3), R 4 is an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or an alkenyl group having 2 to 12 carbon atoms; Ring D is 1,4-cyclohexylene, 1,4-phenylene, 2-fluoro-1,4-phenylene, or 2,6-difluoro-1,4-phenylene; Z 2 is a single bond, carbonyloxy or difluoromethyleneoxy; X 3 and X 4 is hydrogen or fluorine; d is 1, 2, 3 or 4.

5. The liquid crystal composition according to claim 1 or 4, comprising at least one compound selected from the group consisting of compounds represented by formula (2-1) to formula (2-36) and formula (3-1) to formula (3-8) as component B; In formula (2-1) to formula (2-36), R 3 is an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or an alkenyl group having 2 to 12 carbon atoms; In formula (3-1) to formula (3-8), R 4 is an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or an alkenyl group having 2 to 12 carbon atoms; X 3 and X 4 is hydrogen or fluorine.

6. The liquid crystal composition according to claim 4, wherein The ratio of component B is in the range of 5 mass % to 50 mass %.

7. The liquid crystal composition according to claim 1 or 4, comprising at least one compound selected from the compounds represented by formula (4) as component C; In formula (4), R 5 and R 6 is 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, or an alkenyl group having 2 to 12 carbon atoms in which at least one hydrogen atom is replaced by fluorine or chlorine; Ring E and Ring F are 1,4-cyclohexylene, 1,4-phenylene, 2-fluoro-1,4-phenylene or 2,5-difluoro-1,4-phenylene; Z 3 is a single bond, ethylene, vinylene, methyleneoxy or carbonyloxy; e is 1, 2 or 3.

8. The liquid crystal composition according to claim 1, comprising at least one compound selected from the group consisting of compounds represented by formula (4-1) to formula (4-15) as component C; In formula (4-1) to formula (4-15), R 5 and R 6 It is 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 in which at least one hydrogen atom is replaced by fluorine or chlorine, or an alkenyl group having 2 to 12 carbon atoms in which at least one hydrogen atom is replaced by fluorine or chlorine.

9. The liquid crystal composition according to claim 7, wherein: The ratio of component C is in the range of 10 mass % to 85 mass %.

10. The liquid crystal composition according to claim 7, comprising at least one compound selected from the compounds represented by formula (5) as component D; In formula (5), R 7 and R 8 The rings G and J are hydrogen, alkyl having 1 to 12 carbon atoms, alkoxy having 1 to 12 carbon atoms, alkenyl having 2 to 12 carbon atoms, alkenyloxy having 2 to 12 carbon atoms, or alkyl having 1 to 12 carbon atoms in which at least one hydrogen is substituted by fluorine or chlorine; and the rings G and J are 1,4-cyclohexylene, 1,4-cyclohexenylene, tetrahydropyran-2,5-diyl, 1,4-phenylene, 1,4-phenylene in which at least one hydrogen is substituted by fluorine or chlorine, naphthalene-2,6-diyl, naphthalene-2,6-diyl in which at least one hydrogen is substituted by fluorine or chlorine, chromane-2,6-diyl, or chromane-2,6-diyl in which at least one hydrogen is substituted by fluorine or chlorine. orthoalkane-2,6-diyl; Ring I is 2,3-difluoro-1,4-phenylene, 2-chloro-3-fluoro-1,4-phenylene, 2,3-difluoro-5-methyl-1,4-phenylene, 1,8-difluorophenanthrene-2,7-diyl, 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; 4 and Z 5 is a single bond, ethylene, vinylene, methyleneoxy or carbonyloxy; f is 0, 1, 2 or 3, g is 0 or 1; and the sum of f and g is 3 or less.

11. The liquid crystal composition according to claim 7, comprising at least one compound selected from the group consisting of compounds represented by formula (5-1) to formula (5-36) as component D; In formula (5-1) to formula (5-36), R 7 and R 8 It is hydrogen, 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 alkenyloxy group having 2 to 12 carbon atoms, or an alkyl group having 1 to 12 carbon atoms in which at least one hydrogen atom is substituted by fluorine or chlorine.

12. The liquid crystal composition according to claim 10, wherein The ratio of component D is in the range of 1 mass % to 20 mass %.

13. A liquid crystal display element comprising the liquid crystal composition according to any one of claims 1 to 12.

14. The liquid crystal display element according to claim 13, wherein the operating mode is a twisted nematic mode, an electrically controlled birefringence mode, an optically compensated bending mode, an in-plane switching mode, an fringe field switching mode or an electric field induced photoreactive orientation mode, and the driving mode is an active matrix mode.

15. Use of a liquid crystal composition for a liquid crystal display element, wherein the liquid crystal composition is the liquid crystal composition according to any one of claims 1 to 12.

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