CN111826169B - Liquid crystal compositions and uses thereof, and liquid crystal display elements - Google Patents

Abstract

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

Description

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

Technical Field

The present invention relates to a liquid crystal composition and its use, a liquid crystal display element containing the composition, etc. In particular, it relates to a liquid crystal composition with negative dielectric anisotropy, and a liquid crystal display element containing the composition and having modes such as in-plane switching (IPS), vertical alignment (VA), fringe field switching (FFS), and field-induced photoreactive alignment (FPA). It also relates to a polymer-stabilized alignment type liquid crystal display element.

Background Art

In liquid crystal display elements, the classification based on the operation mode of liquid crystal molecules is: 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 classification based on the driving method of the element is 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.

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 among 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. Ideally, it is a response time shorter than 1 millisecond. Therefore, it is preferred that the viscosity of the composition is small. More preferably, the viscosity is small at low temperatures.

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 operation mode. In the VA mode element, the value is in the range of about 0.30μm to about 0.40μm, and in the IPS mode or FFS mode element, the value is in the range of about 0.20μm to about 0.30μm. In these cases, a composition having a large optical anisotropy is preferred for an element 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. The large specific resistance of the composition contributes to the large voltage holding ratio and large contrast of the element. Therefore, a composition having a large specific resistance in the initial stage is preferred. A composition having a large specific resistance after long-term use is preferred. The stability of the composition to light or heat is related to the life of the element. When the stability is high, the life of the element is long. Such characteristics are preferred for AM elements used in liquid crystal monitors, liquid crystal televisions, etc.

In general liquid crystal display elements, the vertical orientation of liquid crystal molecules can be achieved by a specific polyimide alignment film. In polymer sustained alignment (PSA) type liquid crystal display elements, polymers and alignment films are combined. First, a composition to which a small amount of polymerizable compounds are added is injected into the element. Secondly, while applying a voltage between the substrates of the element, ultraviolet rays are irradiated on the composition. The polymerizable compounds are polymerized to form a network structure of the polymer in the composition. In the composition, the polymer can be used to control the orientation of the liquid crystal molecules, so the response time of the element is shortened and the afterimage of the image is improved. This effect of the polymer can be expected in elements with modes such as TN, ECB, OCB, IPS, VA, FFS, and FPA.

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 having an IPS mode or an FFS mode. A composition having positive or negative dielectric anisotropy is used in an AM device of polymer sustained alignment (PSA) type.

[Prior art literature]

[Patent Document]

[Patent Document 1] Japanese Patent Application Laid-Open No. 58-194822

[Patent Document 2] International Publication No. 2012-043387

[Patent Document 3] Japanese Patent Application Laid-Open No. 8-302353

Summary of the invention

[Problems to be solved by the invention]

The subject of the present invention is to provide a liquid crystal composition that 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, low viscosity, appropriate optical anisotropy, large negative dielectric anisotropy, large specific resistance, high light stability, and high thermal stability. Another subject is to provide a liquid crystal composition having a proper balance between at least two of these characteristics. Another subject is to provide a liquid crystal display element containing such a composition. Yet another purpose is to provide an AM element having characteristics such as a short response time, a large voltage holding ratio, a low threshold voltage, a large contrast ratio, and a long life.

[Technical means to solve the problem]

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

In formula (1), ^R1 and ^R2 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 atom is substituted by fluorine or chlorine; ^Z1 , ^Z2 and ^Z3 are a single bond, ethylene, vinylene, methyleneoxy or carbonyloxy.

[Effects of the Invention]

The advantages of the present invention are to provide a liquid crystal composition that fully satisfies at least one of the following characteristics: a high upper temperature limit of the nematic phase, a low lower temperature limit of the nematic phase, low viscosity, appropriate optical anisotropy, large negative dielectric anisotropy, large specific resistance, high light stability, and high thermal stability. Another advantage is to provide a liquid crystal composition having a proper balance between at least two of these characteristics. Another advantage is to provide a liquid crystal display element containing such a composition. Yet another advantage is to provide an AM element having characteristics such as a short response time, a large voltage holding ratio, a low threshold voltage, a large contrast ratio, and a long life.

BRIEF DESCRIPTION OF THE DRAWINGS

none

DETAILED DESCRIPTION

The usage of terms in this specification is as follows. Sometimes the terms "liquid crystal composition" and "liquid crystal display element" are abbreviated 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.

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 not containing the additive. The proportion of the additive is expressed by the mass percentage (mass %) based on the mass of the liquid crystal composition not containing 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. Sometimes parts per million (ppm) is used. The proportion of the polymerization initiator and the polymerization inhibitor is expressed based on the mass of the polymerizable compound as an exception.

Sometimes, the "upper limit temperature of the nematic phase" is abbreviated as the "upper limit temperature". Sometimes, the "lower limit temperature of the nematic phase" is abbreviated 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.

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 in multiple 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 consisting of alkyl, alkoxy and alkenyl. That is, the group represented by Ra and the group represented by Rb may be the same or different.

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).

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 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 limitation. The expression "at least one -CH ₂ - may be substituted with -O-" is sometimes used. In this case, -CH ₂ CH ₂ -CH ₂ - can be converted to -O-CH ₂ -O- by replacing a non-adjacent -CH ₂ - with -O-. However, there is no case where an adjacent -CH ₂ - is substituted with -O-. The reason is that -OO-CH ₂ - (peroxide) is generated in the substitution.

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 groups. Regarding the stereo configuration associated with 1,4-cyclohexylene, in order to increase the upper limit temperature, the trans configuration is preferred over the cis configuration. Since 2-fluoro-1,4-phenylene is left-right asymmetric, there are left-facing (L) and right-facing (R).

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

The present invention includes the following items and the like.

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

In formula (1), ^R1 and ^R2 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 atom is substituted by fluorine or chlorine; ^Z1 , ^Z2 and ^Z3 are a single bond, ethylene, vinylene, methyleneoxy or carbonyloxy.

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

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

In formula (2), ^R3 and ^R4 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 atom is substituted by fluorine or chlorine; Ring A and Ring C are 1,4-cyclohexylene, 1,4-cyclohexenylene, tetrahydropyran-2,5-diyl, 1,4-phenylene, 1,4-phenylene in which at least one hydrogen atom is substituted by fluorine or chlorine, naphthalene-2,6-diyl, naphthalene-2,6-diyl in which at least one hydrogen atom is substituted by fluorine or chlorine, chromane-2,6-diyl, or at least one hydrogen atom is substituted by fluorine or chlorine. A chromane-2,6-diyl group substituted with 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; ^Z4 and ^Z5 are a single bond, ethylene, vinylene, 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 Items 1 to 3, comprising, as Component B, at least one compound selected from the group consisting of compounds represented by Formula (2-1) to Formula (2-35).

In formula (2-1) to formula (2-35), ^R3 and ^R4 are 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.

Item 5. The liquid crystal composition according to Item 3 or Item 4, wherein the ratio of Component B is in the range of 10% by mass to 90% by mass.

Item 6. The liquid crystal composition according to any one of Items 1 to 5, comprising, as Component C, at least one compound selected from the group consisting of compounds represented by Formula (3).

In formula (3), ^R5 and ^R6 are alkyl groups having 1 to 12 carbon atoms, alkoxy groups having 1 to 12 carbon atoms, alkenyl groups having 2 to 12 carbon atoms, alkyl groups having 1 to 12 carbon atoms in which at least one hydrogen atom is replaced by fluorine or chlorine, or alkenyl groups having 2 to 12 carbon atoms in which at least one hydrogen atom is replaced by 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; ^Z6 is a single bond, ethylene, vinylene, methyleneoxy or carbonyloxy; and c is 1 or 2.

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 (3-1) to Formula (3-9).

In formula (3-1) to formula (3-9), ^R5 and ^R6 are alkyl groups having 1 to 12 carbon atoms, alkoxy groups having 1 to 12 carbon atoms, alkenyl groups having 2 to 12 carbon atoms, alkyl groups having 1 to 12 carbon atoms in which at least one hydrogen atom is replaced by fluorine or chlorine, or alkenyl groups having 2 to 12 carbon atoms in which at least one hydrogen atom is replaced by fluorine or chlorine.

Item 8. The liquid crystal composition according to Item 6 or Item 7, wherein the ratio of Component C is in the range of 10% by mass to 90% by mass.

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

In formula (4), ring F and 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 at least one hydrogen in these rings may be substituted by 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 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 Z is a 1,4-diyl group, a 1,5-diyl group, a 1,6-diyl group, a 1,7-diyl group, a 1,8-diyl group, a 2,3-diyl group, a 2,6-diyl group, a 2,7-diyl group, a tetrahydropyran-2,5-diyl group, a 1,3-dioxane-2,5-diyl group, a pyrimidine-2,5-diyl group or a pyridine-2,5-diyl group, in which at least one hydrogen atom is substituted by 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 atom is substituted by fluorine or chlorine; ^Z7 and ^Z8 are single bonds or alkylene groups having 1 to 10 carbon atoms, in which at least one _-CH2- group may be substituted by -O-, -CO-, -COO- or -OCO-, and at least one _-CH2CH2- group may be substituted by -CH=CH-, -C( _CH3 )=CH-, -CH=C(CH3)- or -C( _CH3 )=C( _CH3 )-, and at least one hydrogen in these groups may be substituted by fluorine or chlorine; _P1 to ^P3 are polymerizable groups; ^Sp1 to ^Sp3 are single bonds or alkylene groups having 1 to 10 carbon atoms, in which at least one _-CH2- group may be substituted by -O-, -COO-, -OCO- or -OCOO-, and at least one _-CH2CH2- group may be substituted by -CH=CH-, -C( ^CH3 )=CH-, -CH=C(CH3)- or -C(CH3)=C(CH3 _{) -.} - may be substituted by -CH=CH- or -C≡C-, in which at least one hydrogen may be 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.

Item 10. The liquid crystal composition according to Item 9, wherein in Formula (4), ^P1 to ^P3 are groups selected from the polymerizable groups represented by Formulae (P-1) to (P-5).

In formula (P-1) to formula (P-5), ^M1 to ^M3 are hydrogen, 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 atom is replaced by fluorine or chlorine.

Item 11. The liquid crystal composition according to any one of Items 1 to 10, comprising, as the additive X, at least one compound selected from polymerizable compounds represented by Formula (4-1) to Formula (4-29).

In formula (4-1) to formula (4-29), Sp ¹ to Sp ³ are single bonds or alkylene groups having 1 to 10 carbon atoms, in which at least one -CH ₂ - may be substituted by -O-, -COO-, -OCO- or -OCOO-, and at least one -CH ₂ CH ₂ - may be substituted by -CH＝CH- or -C≡C-, and in these groups, at least one hydrogen may be substituted by fluorine or chlorine; P ⁴ to P ⁶ are polymerizable groups selected from the groups represented by formula (P-1) to formula (P-3);

In formula (P-1) to formula (P-3), ^M1 to ^M3 are hydrogen, 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 atom is replaced by fluorine or chlorine.

Item 12. The liquid crystal composition according to any one of Items 9 to 11, wherein the ratio of the additive X is in the range of 0.03% by mass to 10% by mass.

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

Item 14. The liquid crystal display element according to Item 13, wherein the operation mode of the liquid crystal display element is an IPS mode, a VA mode, a FFS mode or a FPA mode, and the driving method of the liquid crystal display element is an active matrix method.

Item 15. A polymer-stabilized alignment type liquid crystal display element, comprising the liquid crystal composition according to any one of Items 9 to 12, wherein a polymerizable compound in the liquid crystal composition is polymerized.

Item 16. Use of a liquid crystal composition, wherein the liquid crystal composition is the liquid crystal composition according to any one of Items 1 to 12, and is used in a liquid crystal display element.

Item 17. Use of a liquid crystal composition, wherein the liquid crystal composition is the liquid crystal composition according to any one of Items 9 to 12, and is used in a polymer-stabilized alignment type liquid crystal display element.

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, defoaming agents, polymerizable compounds, polymerization initiators, and polymerization inhibitors. (b) An AM element, which contains the composition. (c) The composition further containing a polymerizable compound, and a polymer stabilized alignment (PSA) type AM element containing the composition. (d) A polymer stabilized alignment (PSA) type AM element, which contains the composition, and the polymerizable compound in the composition is polymerized. (e) An element, which contains the composition and has a mode of PC, TN, STN, ECB, OCB, IPS, VA, FFS or FPA. (f) A transmissive element, which contains the composition. (g) The use of the composition, which is used as a composition having a nematic phase. (h) The use of an optically active composition obtained by adding an optically active compound to the composition.

The composition of the present invention is described in the following order. First, 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.

First, the composition 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) and compound (3), 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) and compound (3). Such compounds are mixed into the composition for the purpose of further adjusting the properties.

The composition (b) substantially contains only a liquid crystal compound selected from the group consisting of compound (1), compound (2) and compound (3). "Substantially" means that although the composition (b) may contain additives, it does not contain other liquid crystal compounds. Compared with the composition (a), the number of components of the composition (b) is small. From the perspective of reducing costs, the composition (b) is superior to the composition (a). From the perspective of being able to further adjust the properties by mixing other liquid crystal compounds, the composition (a) is superior to the composition (b).

Second, the main characteristics of the component compounds and the main effects of the compounds on the composition or element are described. Based on the effects of the present invention, 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 0 (zero) means less than S.

Table 2. Properties of liquid crystal compounds

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

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

The main effects of the component compounds are as follows. Compound (1) increases the upper limit temperature. Compound (2) increases dielectric anisotropy. Compound (3) reduces viscosity. Compound (4) is polymerizable and thus forms a polymer by polymerization. The polymer stabilizes the orientation of the liquid crystal molecules, thereby shortening the response time of the element and improving image retention.

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 (1) + compound (3), compound (1) + compound (2) + 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).

In order to increase the upper limit temperature, the preferred ratio of compound (1) is about 3% by mass or more, and in order to reduce the lower limit temperature, the preferred ratio of compound (1) is about 30% 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.

In order to improve the dielectric anisotropy, the preferred ratio of compound (2) is about 10% by mass or more, and in order to reduce the minimum temperature, the preferred ratio of compound (2) is about 90% by mass or less. A further preferred ratio is in the range of about 15% by mass to about 85% by mass. A particularly preferred ratio is in the range of about 20% by mass to about 80% by mass.

In order to reduce the viscosity, the preferred ratio of compound (3) is about 10% by mass or more, and in order to increase the dielectric anisotropy, the preferred ratio of compound (3) is about 90% by mass or less. A further preferred 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.

Compound (4) is added to the composition for the purpose of being suitable for a polymer-stabilized oriented element. In order to orient the liquid crystal molecules, the preferred ratio of compound (4) is about 0.03% by mass or more, and in order to prevent poor display of the element, the preferred ratio of compound (4) is about 10% by mass or less. A further preferred 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% by mass to about 1.0% by mass.

Fourth, the preferred form of the component compound is described. In formula (1), formula (2) and formula (3), R ¹ and R ² are 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 is substituted by fluorine or chlorine. In order to reduce the viscosity, preferably R ¹ or R ² is an alkenyl group having 2 to 12 carbon atoms, and in order to improve the stability, preferably R ¹ or R ² is an alkyl group having 1 to 12 carbon atoms. R ³ and R ⁴ are 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 is substituted by fluorine or chlorine. In order to improve stability, R ³ or R ⁴ is preferably an alkyl group having 1 to 12 carbon atoms, in order to improve dielectric anisotropy, R ³ or R ⁴ is preferably an alkoxy group having 1 to 12 carbon atoms, and in order to reduce viscosity and for low threshold voltage, R ³ or R ⁴ is preferably an alkenyl group having 2 to 12 carbon atoms. R ⁵ and R ⁶ are 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 is substituted by fluorine or chlorine, or an alkenyl group having 2 to 12 carbon atoms in which at least one hydrogen is substituted by fluorine or chlorine. In order to reduce viscosity, R ⁵ or R ⁶ is preferably an alkenyl group having 2 to 12 carbon atoms, and in order to improve stability, R ⁵ or R ⁶ is preferably an alkyl group having 1 to 12 carbon atoms.

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.

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.

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.

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.

Preferred examples of the alkyl group 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. In order to improve the dielectric anisotropy, further preferred examples are 2-fluoroethyl, 3-fluoropropyl, 4-fluorobutyl or 5-fluoropentyl.

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.

Ring A and Ring C 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 A or ring C is 1,4-cyclohexylene, in order to increase the upper limit temperature, the preferred ring A or ring C is tetrahydropyran-2,5-diyl, and in order to increase the optical anisotropy, the preferred ring A or ring C is 1,4-phenylene. The tetrahydropyran-2,5-diyl group 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 (DBFF2), 4,6-difluorodibenzothiophene-3,7-diyl (DBTF2) or 1,1,6,7-tetrafluoroindan-2,5-diyl (InF4).

In order to reduce the viscosity, the preferred ring B is 2,3-difluoro-1,4-phenylene, and in order to increase the dielectric anisotropy, the preferred ring B is 4,6-difluorodibenzothiophene-3,7-diyl.

Ring D and Ring E 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 D or Ring E is preferably 1,4-cyclohexylene, and in order to reduce the lower limit temperature, Ring D or Ring E is preferably 1,4-phenylene.

Z ¹ , Z ² and Z ³ are single bonds, ethylene, vinylene, methyleneoxy or carbonyloxy. In order to reduce viscosity, preferably Z ¹ , Z ² or Z ³ are single bonds. Z ⁴ and Z ⁵ are single bonds, ethylene, vinylene, methyleneoxy or carbonyloxy. In order to reduce viscosity, preferably Z ⁴ or Z ⁵ is a single bond, in order to reduce the minimum temperature, preferably Z ⁴ or Z ⁵ is ethylene, in order to improve dielectric anisotropy, preferably Z ⁴ or Z ⁵ is methyleneoxy. Z ⁶ is a single bond, ethylene, vinylene, methyleneoxy or carbonyloxy. In order to reduce viscosity, preferably Z ⁶ is a single bond.

Divalent groups such as methyleneoxy are asymmetrical. In methyleneoxy, -CH ₂ O- is preferred to -OCH ₂ -. In carbonyloxy, -COO- is preferred 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. In order to reduce the viscosity, a is preferably 1, and in order to increase the upper limit temperature, a is preferably 2 or 3. In order to reduce the viscosity, b is preferably 0, and in order to reduce the lower limit temperature, b is preferably 1. c is 1 or 2. In order to reduce the viscosity, c is preferably 1, and in order to increase the upper limit temperature, c is preferably 2.

In formula (4), ring F and 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 at least one hydrogen in these rings may be substituted by 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 by fluorine or chlorine. Preferably, 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 at least one hydrogen in these rings 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 G is 1,4-phenylene or 2-fluoro-1,4-phenylene.

^Z7 and ^Z8 are single bonds or alkylene groups having 1 to 10 carbon atoms. In the alkylene groups, at least one _-CH2- may be substituted by -O-, -CO-, -COO- or -OCO-, and at least one _-CH2CH2- may be substituted by -CH= _CH- , -C( _CH3 )=CH-, -CH=C( _CH3 )- or -C( _CH3 )=C( _CH3 )-. In these groups, at least one hydrogen may be substituted by fluorine or chlorine. Preferably, ^Z7 or ^Z8 is a single bond, _-CH2CH2- , _-CH2O- , _-OCH2- , -COO- or -OCO-. More preferably _, ^Z7 or ^Z8 is a single bond.

Sp ¹ to Sp ³ are a single bond or an alkylene group having 1 to 10 carbon atoms, in which at least one -CH ₂ - may be substituted by -O-, -COO-, -OCO- or -OCOO-, at least one -CH ₂ CH ₂ - may be substituted by -CH＝CH- or -C≡C-, and in these groups, at least one hydrogen may be substituted by fluorine or chlorine. Preferred Sp ¹ to Sp ³ are a single bond, -CH ₂ CH ₂ -, -CH ₂ O-, -OCH ₂ -, -COO-, -OCO-, -CO-CH＝CH- or -CH＝CH-CO-. Further preferred Sp ¹ to Sp ³ are 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. Preferably e, f or g is 1 or 2.

^P1 to ^P3 are polymerizable groups. Preferred ^P1 to ^P3 are polymerizable groups selected from the groups represented by formula (P-1) to (P-5). Further preferred ^P1 to ^P3 are groups represented by formula (P-1), formula (P-2) or formula (P-3). Particularly preferred ^P1 to ^P3 are groups represented by formula (P-1) or formula (P-2). Most preferred ^P1 to ^P3 are groups represented by formula (P-1). The preferred group represented by formula (P-1) is -OCO-CH=CH ₂ or -OCO-C(CH ₃ )=CH _2. The wavy lines in formula (P-1) to (P-5) indicate bonding sites.

In formula (P-1) to formula (P-5), ^M1 to ^M3 are hydrogen, 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 by fluorine or chlorine. In order to improve reactivity, ^M1 to ^M3 are preferably hydrogen or methyl. More preferably, ^M1 is hydrogen or methyl, and more preferably, ^M2 or ^M3 is hydrogen.

In formula (4-1) to formula (4-29), ^P4 to ^P6 are groups represented by formula (P-1) to formula (P-3). Preferred ^P4 to ^P6 are formula (P-1) or formula (P-2). Further preferred formula (P-1) is -OCO-CH= _CH2 or -OCO-C( _CH3 )= _CH2 . The wavy lines in formula (P-1) to formula (P-3) indicate bonding sites.

Fifth, preferred component compounds are shown. Preferred compound (1) is a compound in which ^R1 is an alkenyl group having 2 to 12 carbon atoms and ^R2 is an alkyl group having 1 to 12 carbon atoms. Further preferred compound (1) is a compound in which ^R1 is an alkenyl group having 2 to 5 carbon atoms and ^R2 is an alkyl group having 1 to 5 carbon atoms. Particularly preferred compound (1) is a compound in which ^R1 is an alkenyl group having 2 or 3 carbon atoms and ^R2 is an alkyl group having 2 or 3 carbon atoms.

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

Preferred compound (3) is compound (3-1) to compound (3-9) described in item 7. Among these compounds, it is preferred that at least one of component C is compound (3-1), compound (3-3), compound (3-5), compound (3-6), compound (3-8) or compound (3-9). It is preferred that at least two of component C are a combination of compound (3-1) and compound (3-3), compound (3-1) and compound (3-5), or compound (3-1) and compound (3-6).

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

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 impart a torsion angle, the optically active compound is added to the composition. Examples of such compounds are compounds (5-1) to compounds (5-5). 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.

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 is used for a long time, an antioxidant such as compound (6-1) to compound (6-3) may be further added to the composition.

Compound (6-2) 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 is 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.

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 (7-1) to (7-16), 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.

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 (8-1) to (8-7) 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.

In order to be suitable for the element of 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 about 0.01 mass % to about 10 mass %. In order to prevent bubbling, 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 more than 1ppm, and in order to prevent poor display, the preferred ratio of the defoamer is about 1000ppm or less. And then the preferred ratio is about 1ppm to about 500ppm.

In order to be suitable for polymer stable orientation (PSA) type elements, a polymerizable compound is used. Compound (4) is suitable for the purpose. A polymerizable compound different from compound (4) and compound (4) can be added to the composition together. 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 proportion of compound (4) is 10% by mass or more. Further preferred proportion is 50% by mass or more. Particularly preferred proportion is 80% by mass or more. The most preferred proportion is 100% by mass.

A polymerizable compound such as compound (4) polymerizes by ultraviolet irradiation. The polymerization can also be carried out in the presence of a suitable initiator such as a photopolymerization initiator. Suitable conditions for polymerization, suitable types of initiators, and suitable amounts are known to those skilled in the art and are described in the literature. For example, Irgacure 651 (registered trademark; BASF), Irgacure 184 (registered trademark; BASF), or Darocur 1173 (registered trademark; BASF) as photopolymerization initiators are suitable for free radical polymerization. The preferred proportion of the photopolymerization initiator is in the range of about 0.1% by mass to about 5% by mass based on the total mass of the polymerizable compound. A further preferred proportion is in the range of about 1% by mass to about 3% by mass.

When storing a polymerizable compound such as compound (4), 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.

Seventh, the synthesis method of the component compounds is described. These compounds can be synthesized by known methods. Example synthesis methods. Compound (1) is synthesized by the method described in Japanese Patent Laid-Open No. 58-194822. Compound (2-1) is synthesized by the method described in Japanese Patent Publication No. 2-503441. Compound (3-5) is synthesized by the method described in Japanese Patent Laid-Open No. 57-165328. Compound (4-18) is synthesized by the method described in Japanese Patent Laid-Open No. 7-101900. Antioxidants are commercially available. Compound (6-1) can be obtained from Sigma-Aldrich Corporation. Compound (6-2) and the like are synthesized by the method described in the specification of U.S. Patent No. 3,660,505.

Compounds for which no synthesis method is described can be synthesized by methods described in books such as Organic Syntheses (John Wiley & Sons, Inc), Organic Reactions (John Wiley & Sons, Inc), Comprehensive Organic Synthesis (Pergamon Press), and New Experimental Chemistry Lectures (Maruzen). 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.

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 trial and error. 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.

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 relative to the glass substrate may be parallel or vertical. These elements may 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 formed by forming a three-dimensional network polymer in the composition.

[Example]

The present invention is described in more detail by way of examples. The present invention is not limited to 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 compound, composition and element are measured by the methods described below.

NMR analysis: DRX-500 manufactured by Bruker BioSpin was used for the measurement. In the measurement of ¹ H-NMR, the sample was dissolved in a deuterated solvent such as CDCl ₃ , and the measurement was performed at room temperature under the conditions of 500 MHz and 16 cumulative times. Tetramethylsilane was used as an internal standard. In the measurement of ¹⁹ F-NMR, CFCl ₃ was used as an internal standard and the measurement was performed with a cumulative number of 24 times. In the description of the nuclear magnetic resonance spectrum, s refers to singlet, d refers to doublet, t refers to triplet, q refers to quartet, quin refers to quintet, sex refers to sextet, m refers to multiplet, and br refers to broad.

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.

The solvent used to dilute the sample can be 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.

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.

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 the smectic phase (or crystal) precipitates at 25°C under the said 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.

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

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.

(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 the "upper limit temperature".

(2) Lower limit temperature of nematic phase (T _C ; °C): A sample having a nematic phase was placed in a glass bottle and stored in a freezer at 0°C, -10°C, -20°C, -30°C, and -40°C for 10 days, and the liquid crystal phase was observed. For example, when the sample remains in the nematic phase at -20°C and changes to a crystalline or smectic phase at -30°C, it is recorded as T _C <-20°C. The lower limit temperature of the nematic phase is sometimes simply referred to as "lower limit temperature".

(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.

(4) Viscosity (rotational viscosity; γ1; measured at 25°C; mPa·s): The measurement was performed using the LCM-2 rotational viscosity measurement system of TOYO Technica Co., Ltd. The sample was injected into a VA element in which the interval (cell gap) between two glass substrates was 10 μm. A rectangular wave (55 V, 1 ms) was applied to the element. The peak current and peak time of the transient current generated by the application were measured. The rotational viscosity value was obtained using these measured values and the dielectric anisotropy. The dielectric anisotropy was measured using the method described in measurement (6).

(5) Optical anisotropy (refractive index anisotropy; Δn; measured at 25°C): Measured using light of 589 nm wavelength with an Abbe refractometer equipped with a polarizing plate on the eyepiece. After rubbing the surface of the main prism in one direction, the sample is dropped 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 according to the formula Δn = n∥ - n⊥.

(6) Dielectric anisotropy (Δε; measured at 25°C): The dielectric anisotropy value was calculated according to the formula Δε=ε∥-ε⊥. The dielectric constants (ε∥ and ε⊥) were measured as follows.

1) Determination of dielectric constant (ε∥): Apply a solution of octadecyltriethoxysilane (0.16 mL) in ethanol (20 mL) on a thoroughly cleaned glass substrate. After rotating the glass substrate using a rotator, heat it at 150°C for 1 hour. Place a sample in a VA element with a gap (cell gap) of 4 μm between two glass substrates, and seal the element with an adhesive that cures with ultraviolet light. Apply a sine wave (0.5 V, 1 kHz) to the element, and after 2 seconds, measure the dielectric constant (ε∥) in the long axis direction of the liquid crystal molecules.

2) Determination of dielectric constant (ε⊥): A polyimide solution is applied to a fully cleaned glass substrate. After the glass substrate is calcined, the obtained orientation film is subjected to a rubbing treatment. A sample is placed in a TN element with a spacing (cell gap) of 9 μm between two glass substrates and a twist angle of 80 degrees. A sine wave (0.5 V, 1 kHz) is applied to the element, and after 2 seconds, the dielectric constant (ε⊥) of the liquid crystal molecule in the short axis direction is measured.

(7) Threshold voltage (Vth; measured at 25°C; V): The measurement was performed using an LCD5100 luminance meter manufactured by Otsuka Electronics Co., Ltd. The light source was a halogen lamp. A sample was placed in a normally black mode VA element in which the distance between two glass substrates (cell gap) was 4 μm and the rubbing direction was antiparallel, and the element was sealed using an adhesive that was cured by ultraviolet light. The voltage applied to the element (60 Hz, rectangular wave) was increased stepwise from 0 V in units of 0.02 V to 20 V. 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 reached a maximum and the transmittance was 0% when the light amount reached a minimum. The threshold voltage is represented by the voltage when the transmittance becomes 10%.

(8) Voltage holding ratio (VHR-1; 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 hardened by ultraviolet rays after the sample is placed. A pulse voltage (5 V, 60 microseconds) is applied to the TN element for charging. The decaying voltage is measured over a period of 16.7 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.

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

(10) Voltage holding ratio (VHR-3; measured at 25°C; %): After irradiation with ultraviolet rays, the voltage holding ratio is measured to evaluate the stability against ultraviolet rays. The TN element used for the measurement has a polyimide orientation film and a cell gap of 5 μm. The sample is injected into the element and irradiated with light for 20 minutes. The light source is an ultra-high pressure mercury lamp USH-500D (manufactured by Ushio Electric), and the distance between the element and the light source is 20 cm. In the measurement of VHR-3, the attenuated voltage is measured within a period of 16.7 milliseconds. A composition having a large VHR-3 has a large stability against ultraviolet rays. VHR-3 is preferably 90% or more, and more preferably 95% or more.

(11) Voltage holding ratio (VHR-4; measured at 25°C; %): After heating the TN device injected with the sample in a thermostatic chamber at 80°C for 500 hours, the voltage holding ratio was measured to evaluate the thermal stability. In the VHR-4 measurement, the decaying voltage was measured over a period of 16.7 milliseconds. A composition having a large VHR-4 has a high thermal stability.

(12) Response time (τ; measured at 25°C; ms): The measurement was performed using an LCD5100 luminance meter manufactured by Otsuka Electronics Co., Ltd. The light source was a halogen lamp. The low-pass filter was set to 5 kHz. A sample was placed in a normally black mode VA element in which the distance between two glass substrates (cell gap) was 4 μm and the rubbing directions were antiparallel. The element was sealed with an adhesive that was cured by ultraviolet light. A rectangular wave (60 Hz, 10 V, 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 reached a maximum, the transmittance was considered to be 100%, and when the amount of light reached a minimum, the transmittance was considered to be 0%. The response time is represented by the time required for the transmittance to change from 90% to 10% (fall time; milliseconds).

(13) 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)}.

(14) Line image sticking (Line Image Sticking Parameter; LISP; %): Line image sticking is generated by applying electrical stress to the liquid crystal display element. The brightness of the area where the line image sticking exists and the brightness of the remaining area are measured. The ratio of brightness reduction due to the line image sticking is calculated, and the size of the line image sticking is expressed by the ratio.

14a) Measurement of brightness: An imaging colorimeter (PM-1433F-0, manufactured by Radiant Zemax) was used to capture an image of the component. The image was analyzed using software (Prometric 9.1, manufactured by Radiant Imaging) to calculate the brightness of each region of the component. A light-emitting diode (LED) backlight with an average brightness of 3500 cd/m ² was used as the light source.

14b) Setting of stress voltage: Place a sample in an FFS element (16 units of 4 vertical units × 4 horizontal units) with a cell gap of 3.5μm and a matrix structure, and seal the element with an adhesive that cures by ultraviolet rays. Polarizing plates are arranged on the upper and lower surfaces of the element in a manner that the polarization axes are orthogonal. Irradiate the element with light, and apply voltage (rectangular wave, 60Hz). Increase the voltage stepwise by 0.1V in the range of 0V to 7.5V, and measure the brightness of the transmitted light at each voltage. The voltage when the brightness reaches the maximum is abbreviated as V255. The voltage when the brightness reaches 21.6% of V255 (i.e., 127 steps) is abbreviated as V127.

14c) Stress conditions: V255 (rectangular wave, 30 Hz) and 0.5 V (rectangular wave, 30 Hz) were applied to the device at 60°C for 23 hours to display a checker pattern. Then, V127 (rectangular wave, 0.25 Hz) was applied and the brightness was measured under the conditions of an exposure time of 4000 milliseconds.

14d) Calculation of line afterimage: The calculation uses 4 units in the central part of the 16 units (2 units vertically × 2 units horizontally). The 4 units are divided into 25 areas (5 units vertically × 5 units horizontally). The average brightness of the 4 areas located at the four corners (2 units vertically × 2 units horizontally) is simply recorded as brightness A. The areas excluding the areas at the four corners from the 25 areas are cross-shaped. Among the 4 areas excluding the central intersection area from the cross-shaped area, the minimum brightness is simply recorded as brightness B. The line afterimage is calculated according to the following formula. (Line afterimage) = (Brightness A-Brightness B)/Brightness A×100.

(15) Ductility: The ductility of the additive is qualitatively evaluated by applying voltage to the element and measuring the brightness. The brightness is measured in the same manner as in item 14a. The voltage (V127) is set in the same manner as in item 14b. A VA element is used instead of an FFS element. The brightness is measured as follows. First, a DC voltage (2 V) is applied to the element for 2 minutes. Next, V127 (rectangular wave, 0.05 Hz) is applied, and the brightness is measured under an exposure time of 4000 milliseconds. The ductility is evaluated based on the results.

(16) Response time (τ-2; measured at -20°C; ms): The measurement was performed using an LCD5100 luminance meter manufactured by Otsuka Electronics Co., Ltd. The light source was a halogen lamp. The low-pass filter was set to 5 kHz. A sample was placed in a normally black mode VA element in which the distance between two glass substrates (cell gap) was 4 μm and the rubbing directions were antiparallel. The element was sealed with an adhesive that was cured by ultraviolet light. A rectangular wave (60 Hz, 10 V, 0.5 seconds) was applied to the element. At this time, light was irradiated from the vertical direction to measure the amount of light passing through the element. When the amount of light reached a maximum, the transmittance was considered to be 100%, and when the amount of light reached a minimum, the transmittance was considered to be 0%. The response time is represented by the time required for the transmittance to change from 90% to 10% (fall time; milliseconds).

(17) Response time (τ-3; measured at -30°C; ms): The measurement was performed using an LCD5100 luminance meter manufactured by Otsuka Electronics Co., Ltd. The light source was a halogen lamp. The low-pass filter was set to 5 kHz. A sample was placed in a normally black mode VA element in which the distance between two glass substrates (cell gap) was 4 μm and the rubbing directions were antiparallel. The element was sealed with an adhesive that was cured by ultraviolet light. A rectangular wave (60 Hz, 10 V, 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 reached a maximum, the transmittance was considered to be 100%, and when the amount of light reached a minimum, the transmittance was considered to be 0%. The response time is represented by the time required for the transmittance to change from 90% to 10% (fall time; milliseconds).

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 numbers in parentheses after the symbols correspond to the numbers of the compounds. 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. Finally, the characteristic values of the composition are summarized.

Table 3 Expression of compounds using symbols

R-(A ₁ )-Z ₁ -·····-Z _n -(A _n )-R'

[Example 1]

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

[Comparative Example 1]

The compound (1) of Example 1 was not included and the upper limit temperature of the nematic phase was adjusted in the same manner.

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

[Example 2]

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

[Example 3]

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

[Example 4]

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

[Example 5]

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

[Example 6]

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

[Example 7]

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

[Example 8]

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

[Example 9]

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

[Example 10]

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

[Example 11]

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

[Example 12]

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

[Example 13]

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

[Example 14]

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

[Example 15]

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

[Example 16]

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

[Example 17]

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

[Example 18]

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

[Example 19]

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

[Example 20]

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

[Example 21]

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

[Example 22]

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

The lower limit temperature of the nematic phase of the composition of Comparative Example 1 is -10°C, and the rotational viscosity is 208.9 mPa·s. On the other hand, the lower limit temperature of the nematic phase of the composition of Example 1 is -20°C, and the rotational viscosity is 187.9 mPa·s. As described above, compared with the composition of the comparative example, the lower limit temperature of the nematic phase of the composition of the example is low and has a small rotational viscosity. Therefore, it can be concluded that the liquid crystal composition of the present invention has excellent properties.

[Industrial Applicability]

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

Claims (13)

1. A liquid crystal composition containing at least one compound selected from the group consisting of a compound represented by formula (1) as a component a, at least one compound selected from the group consisting of a compound represented by formula (2) as a component B, and at least one compound selected from the group consisting of a compound represented by formula (3) as a component C, and at least one compound selected from the group consisting of a polymerizable compound represented by formula (4) as an additive X, the liquid crystal composition being composed of the component a, the component B, and the component C and having negative dielectric anisotropy:

in the formula (1), R ¹ R is R ² Is hydrogen, alkyl of 1 to 12 carbon atoms, alkoxy of 1 to 12 carbon atoms, alkenyl of 2 to 12 carbon atoms, alkenyloxy of 2 to 12 carbon atoms, or alkyl of 1 to 12 carbon atoms in which at least one hydrogen is substituted with fluorine or chlorine; z is Z ¹ 、Z ² Z is as follows ³ Is a single bond, ethylene, vinylidene, methyleneoxy or carbonyloxy,

in the formula (2), R ³ R is R ⁴ Is hydrogen, alkyl of 1 to 12 carbon atoms, alkoxy of 1 to 12 carbon atoms, alkenyl of 2 to 12 carbon atoms, alkenyloxy of 2 to 12 carbon atoms, or alkyl of 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 substituted with at least one hydrogen by fluorine or chlorine, naphthalene-2, 6-diyl substituted with at least one hydrogen by fluorine or chlorine, chromane-2, 6-diyl, or chromane-2, 6-diyl substituted with at least one hydrogen 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 1,6, 7-tetrafluoroindan-2, 5-diyl; z is Z ⁴ Z is as follows ⁵ Is 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,

in the formula (3), R ⁵ R is R ⁶ Is an alkyl group of 1 to 12 carbon atoms, an alkoxy group of 1 to 12 carbon atoms, an alkenyl group of 2 to 12 carbon atoms, an alkyl group of 1 to 12 carbon atoms in which at least one hydrogen is substituted with fluorine or chlorine, or an alkenyl group of 2 to 12 carbon atoms in which 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; z is Z ⁶ Is a single bond, ethylene, vinylidene, methyleneoxy or carbonyloxy; c is 1 or 2.

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 group consisting of compounds represented by the formulas (2-1) to (2-35) as component B:

in the formulae (2-1) to (2-35), R ³ R is R ⁴ Is hydrogen, alkyl of 1 to 12 carbon atoms, alkoxy of 1 to 12 carbon atoms, alkenyl of 2 to 12 carbon atoms, alkenyloxy of 2 to 12 carbon atoms, or alkyl of 1 to 12 carbon atoms in which at least one hydrogen is substituted with fluorine or chlorine.

4. The liquid crystal composition according to claim 1, wherein the proportion of the component B is in the range of 10 to 90 mass%.

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

in the formulae (3-1) to (3-9), R ⁵ R is R ⁶ Is C1-12 alkyl, C1-12 alkoxyA group, an alkenyl group of 2 to 12 carbon atoms, an alkyl group of 1 to 12 carbon atoms in which at least one hydrogen is substituted with fluorine or chlorine, or an alkenyl group of 2 to 12 carbon atoms in which at least one hydrogen is substituted with fluorine or chlorine.

6. The liquid crystal composition according to claim 1, wherein the proportion of the component C is in the range of 10 to 90 mass%.

7. The liquid crystal composition according to claim 1, wherein in formula (4), P ¹ To P ³ Is a group selected from the polymerizable groups represented by the formulas (P-1) to (P-5):

in the formulae (P-1) to (P-5), M ¹ To M ³ Is hydrogen, fluorine, alkyl of 1 to 5 carbon atoms, or alkyl of 1 to 5 carbon atoms in which at least one hydrogen is substituted with fluorine or chlorine.

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

in the formulas (4-1) to (4-29), sp ¹ To Sp ³ An alkylene group having 1 to 10 carbon atoms or a single bond, at least one of the alkylene groups-CH ₂ -can be substituted by-O-, -COO-, -OCO-or-OCOO-, at least one-CH ₂ CH ₂ -may be substituted by-ch=ch-or-c≡c-, in which groups at least one hydrogen may be substituted by fluorine or chlorine; p (P) ⁴ To P ⁶ Is a polymerizable group selected from groups represented by the formulas (P-1) to (P-3);

in the formulae (P-1) to (P-3), M ¹ To M ³ Is hydrogen, fluorine, alkyl of 1 to 5 carbon atoms, or alkyl of 1 to 5 carbon atoms in which at least one hydrogen is substituted with fluorine or chlorine.

9. The liquid crystal composition according to claim 1, wherein the proportion of the additive X is in the range of 0.03 to 10 mass%.

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

11. The liquid crystal display device according to claim 10, wherein the operation mode of the liquid crystal display device is an in-plane switching mode, a vertical alignment mode, a fringe field switching mode, or an electric field induced photoreaction alignment mode, and the driving mode of the liquid crystal display device is an active matrix mode.

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

13. Use of the liquid crystal composition according to claim 1 in a liquid crystal display element of polymer stable alignment.