阅读说明：本技术 液晶组合物及其用途、以及液晶显示元件 (Liquid crystal composition, use thereof, and liquid crystal display element ) 是由 森崇徳 朝仓利树 斋藤将之 于 2019-12-26 设计创作，主要内容包括：本发明提供一种液晶组合物及其用途、以及液晶显示元件,所述液晶组合物在上限温度高、下限温度低、粘度小、光学各向异性适当、负介电各向异性大、比电阻大、对光的稳定性高、对热的稳定性高之类的特性中,充分满足至少一种特性或关于至少两种特性而具有适当平衡。本发明的液晶组合物含有选自式(1)所表示的化合物中至少一种化合物作为添加物X,也可含有作为成分A的具有大的负介电各向异性的特定化合物、作为成分B的具有高的上限温度或小的粘度的特定化合物或作为添加物Y的具有聚合性基的特定化合物。(The present invention provides a liquid crystal composition which satisfies at least one of the characteristics of high upper limit temperature, low lower limit temperature, low viscosity, appropriate optical anisotropy, large negative dielectric anisotropy, large specific resistance, high stability to light and high stability to heat, or has an appropriate balance between at least two of the characteristics, and a use thereof, and a liquid crystal display element. The liquid crystal composition of the present invention contains at least one compound selected from the compounds represented by formula (1) as an additive X, and may contain a specific compound having a large negative dielectric anisotropy as a component a, a specific compound having a high upper limit temperature or a small viscosity as a component B, or a specific compound having a polymerizable group as an additive Y.)

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

in the formula (1), R^aHydrogen, a group represented by the formula (F), an alkyl group having 1 to 30 carbon atoms, an alicyclic hydrocarbon group having 3 to 30 carbon atoms or an aromatic hydrocarbon group having 6 to 30 carbon atoms, at least one of the group consisting of an alkyl group, an alicyclic hydrocarbon group and an aromatic hydrocarbon group₂-may be substituted by-S-, -O-, -NH-or-CO-, at least one-CH₂-CH₂-may be substituted by-CH-or-C ≡ C-, of which groups at least one hydrogen may be substituted by halogen; r^bIs an alkyl group having 1 to 30 carbon atoms, an alicyclic hydrocarbon group having 3 to 30 carbon atoms or an aromatic hydrocarbon group having 6 to 30 carbon atoms, wherein at least one-CH group₂-may be substituted by-S-, -O-, -NH-or-CO-, at least one-CH₂-CH₂-may be substituted by-CH-or-C ≡ C-, of which groups at least one hydrogen may be substituted by halogen; z^aAnd Z^cIs a single bond or an alkylene group having 1 to 30 carbon atoms, in which at least one-CH group₂-may be substituted by-O-, -NH-or-CO-, at least one-CH₂-CH₂-may be substituted by-CH-or-C ≡ C-, at least one hydrogen may be substituted by halogen; z^bA single bond, an alkylene group having 1 to 30 carbon atoms, an alicyclic hydrocarbon group having 3 to 30 carbon atoms or an aromatic hydrocarbon group having 6 to 30 carbon atoms,at least one-CH₂-may be substituted by-S-, -O-, -NH-or-CO-, at least one-CH₂-CH₂-may be substituted by-CH-or-C ≡ C-, of which at least one hydrogen may be substituted by halogen or a group represented by formula (F); s is sulfur; n is 0, 1,2, 3 or 4; p is 0 or 1;

in the formula (F), R^cIs an alkyl group having 1 to 30 carbon atoms, an alicyclic hydrocarbon group having 3 to 30 carbon atoms or an aromatic hydrocarbon group having 6 to 30 carbon atoms, wherein at least one-CH group₂-may be substituted by-S-, -O-, -NH-or-CO-, at least one-CH₂-CH₂-may be substituted by-CH-or-C ≡ C-, of which groups at least one hydrogen may be substituted by halogen; z^dIs a single bond or an alkylene group having 1 to 30 carbon atoms, in which at least one-CH group₂-may be substituted by-O-, -NH-or-CO-, at least one-CH₂-CH₂-may be substituted by-CH-or-C ≡ C-, at least one hydrogen may be substituted by halogen; s is sulfur; m is 0, 1,2, 3 or 4; r is 0 or 1.

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

in the formulae (1-1) to (1-4), R^fHydrogen, an alkyl group having 1 to 20 carbon atoms, an alicyclic hydrocarbon group having 3 to 20 carbon atoms or an aromatic hydrocarbon group having 6 to 20 carbon atoms, wherein at least one-CH group₂-may be substituted by-S-, -O-or-CO-, at least one-CH₂-CH₂-may be substituted by-CH ═ CH-; r^g、R^h、RⁱAnd R^jHydrogen, alkyl of 1 to 5 carbon atoms, at least one-CH of these groups₂-may be substituted by-O-or-CO-, at least one-CH₂-CH₂-may be substituted by-CH ═ CH-,at least one hydrogen may be substituted with a group represented by the formula (F-1); r^dAnd R^eIs an alkyl group having 1 to 20 carbon atoms, an alicyclic hydrocarbon group having 3 to 20 carbon atoms or an aromatic hydrocarbon group having 6 to 20 carbon atoms, wherein at least one-CH group₂-may be substituted by-S-, -O-or-CO-, at least one-CH₂-CH₂-may be substituted by-CH ═ CH-; z^eAnd Z^fIs a single bond or an alkylene group having 1 to 10 carbon atoms, in which at least one-CH group₂-may be substituted by-O-, -NH-or-CO-, at least one-CH₂-CH₂-may be substituted by-CH ═ CH-; z^gIs alkylene with 1 to 6 carbon atoms, in which at least one-CH₂-may be substituted by-S-, -O-, -NH-or-CO-, at least one-CH₂-CH₂-may be substituted by-CH ═ CH-; s is sulfur; n is¹And n²Is 0, 1,2 or 3;

in the formula (F-1), R^jIs an alkyl group having 1 to 20 carbon atoms, an alicyclic hydrocarbon group having 3 to 20 carbon atoms or an aromatic hydrocarbon group having 6 to 20 carbon atoms, wherein at least one-CH group₂-may be substituted by-O-or-CO-, at least one-CH₂-CH₂-may be substituted by-CH ═ CH-; z^hIs a single bond or an alkylene group having 1 to 10 carbon atoms, in which at least one-CH group₂-may be substituted by-O-or-CO-; s is sulfur; m is¹Is 0, 1,2 or 3; r is¹Is 0 or 1.

3. The liquid crystal composition according to claim 1, wherein the proportion of the additive X is in the range of 0.0001 to 2 mass%.

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

in the formula (2), R^2aAnd R^2bIs hydrogen, alkyl group having 1 to 12 carbon atoms, alkoxy group having 1 to 12 carbon atoms, alkenyl group having 2 to 12 carbon atoms, alkenyloxy group having 2 to 12 carbon atoms, or alkyl group having 1 to 12 carbon atoms in which at least one hydrogen is substituted with fluorine or chlorine; ring A and ring C are 1, 4-cyclohexylene, 1, 4-cyclohexenylene, tetrahydropyran-2, 5-diyl, 1, 4-phenylene in which at least one hydrogen is substituted by fluorine or chlorine, naphthalene-2, 6-diyl in which at least one hydrogen is substituted by fluorine or chlorine, chroman-2, 6-diyl in which at least one hydrogen is substituted by fluorine or chlorine, or chroman-2, 6-diyl in which at least one hydrogen is substituted by fluorine or chlorine; ring B is 2, 3-difluoro-1, 4-phenylene, 2-chloro-3-fluoro-1, 4-phenylene, 2, 3-difluoro-5-methyl-1, 4-phenylene, 3,4, 5-trifluoronaphthalene-2, 6-diyl, 7, 8-difluorochromane-2, 6-diyl, 3,4,5, 6-tetrafluorofluorene-2, 7-diyl, 4, 6-difluorodibenzofuran-3, 7-diyl, 4, 6-difluorodibenzothiophene-3, 7-diyl, or 1,1,6, 7-tetrafluoroindan-2, 5-diyl; z^2aAnd Z^2bIs 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.

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

in the formulae (2-1) to (2-35), R^2aAnd R^2bIs hydrogen, alkyl group having 1 to 12 carbon atoms, alkoxy group having 1 to 12 carbon atoms, alkenyl group having 2 to 12 carbon atoms, alkenyloxy group having 2 to 12 carbon atoms, or alkyl group having 1 to 12 carbon atoms wherein at least one hydrogen is substituted with fluorine or chlorine.

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

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

in the formula (3), R^3aAnd R^3bIs alkyl group having 1 to 12 carbon atoms, alkoxy group having 1 to 12 carbon atoms, alkenyl group having 2 to 12 carbon atoms, or alkenyl group having 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^3aIs a single bond, ethylene, vinylidene, methyleneoxy or carbonyloxy; c is 1,2 or 3.

8. The liquid crystal composition according to claim 4, which contains at least one compound selected from the compounds represented by formula (3) as component B:

in the formula (3), R^3aAnd R^3bIs alkyl group having 1 to 12 carbon atoms, alkoxy group having 1 to 12 carbon atoms, alkenyl group having 2 to 12 carbon atoms, or alkenyl group having 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^3aIs a single bond, ethylene, vinylidene, methyleneoxy or carbonyloxy; c is 1,2 or 3.

9. The liquid crystal composition according to claim 1, which contains at least one compound selected from the group consisting of compounds represented by formulae (3-1) to (3-13) as component B:

in formulae (3-1) to (3-13), R^3aAnd R^3bIs 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 is substituted with fluorine or chlorine.

10. The liquid crystal composition according to claim 5, which contains at least one compound selected from the group consisting of compounds represented by formulae (3-1) to (3-13) as component B:

in formulae (3-1) to (3-13), R^3aAnd R^3bIs 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 is substituted with fluorine or chlorine.

11. The liquid crystal composition according to claim 7, wherein the proportion of the component B is in the range of 10 to 90 mass%.

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

in the formula (4), the ring F and the ring I are cyclohexyl, cyclohexenyl, phenyl, 1-naphthyl, 2-naphthyl, tetrahydropyran-2-yl, 1, 3-dioxane-2-ylPyrimidine-2-yl or pyridine-2-yl, in which at least one hydrogen 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-1, 4-diyl, naphthalene-1, 5-diyl, naphthalene-1, 6-diyl, naphthalene-1, 7-diyl, naphthalene-1, 8-diyl, naphthalene-2, 3-diyl, naphthalene-2, 6-diyl, naphthalene-2, 7-diyl, tetrahydropyran-2, 5-diyl, 1, 3-dioxane-2, 5-diyl, pyrimidine-2, 5-diyl or pyridine-2, 5-diyl, and in these rings, at least one hydrogen may be substituted with fluorine, chlorine, an alkyl group having a carbon number of 1 to 12, an alkoxy group having a carbon number of 1 to 12, Or at least one hydrogen is substituted by a fluorine or chlorine substituted alkyl group of carbon number 1 to 12; z^4aAnd Z^4bIs a single bond or an alkylene group having 1 to 10 carbon atoms, in which at least one-CH group₂-may be substituted by-O-, -CO-, -COO-or-OCO-, at least one-CH₂-CH₂-may be via-CH ═ CH-, -C (CH)₃)＝CH-、-CH＝C(CH₃) -or-C (CH)₃)＝C(CH₃) -substitution, of which at least one hydrogen may be substituted by fluorine or chlorine; p^4a、P^4bAnd P^4cIs a polymerizable group; sp^4a、Sp^4bAnd Sp^4cIs a single bond or an alkylene group having 1 to 10 carbon atoms, in which at least one-CH group₂At least one-CH which may be substituted by-O-, -COO-, -OCO-or-OCOO-)₂-CH₂-may be substituted by-CH ═ CH-or-C ≡ C-, at least one of these groups being substituted by fluorine or chlorine; d is 0, 1 or 2; e. f and g are 0, 1,2, 3 or 4; and the sum of e, f and g is 1 or more.

13. The liquid crystal composition according to claim 12, wherein in the formula (4), P^4a、P^4bAnd P^4cIs a group selected from the polymerizable groups represented by the formulae (P-1) to (P-5):

in the formulae (P-1) to (P-5),M¹、M²and M³Hydrogen, fluorine, an alkyl group having 1 to 5 carbon atoms, or an alkyl group having 1 to 5 carbon atoms in which at least one hydrogen is substituted with fluorine or chlorine.

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

in formulae (4-1) to (4-29), Sp^4a、Sp^4bAnd Sp^4cIs a single bond or an alkylene group having 1 to 10 carbon atoms, in which at least one-CH group₂At least one-CH which may be substituted by-O-, -COO-, -OCO-or-OCOO-)₂-CH₂-may be substituted by-CH ═ CH-or-C ≡ C-, at least one of these groups being substituted by fluorine or chlorine; p^4d、P^4eAnd P^4fIs a polymerizable group selected from the group represented by the formulae (P-1) to (P-3);

in the formulae (P-1) to (P-3), M¹、M²And M³Hydrogen, fluorine, an alkyl group having 1 to 5 carbon atoms, or an alkyl group having 1 to 5 carbon atoms in which at least one hydrogen is substituted with fluorine or chlorine.

15. The liquid crystal composition according to claim 12, wherein the proportion of the additive Y is in the range of 0.03 to 10 mass%.

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

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

18. A polymer-stabilized alignment type liquid crystal display element comprising the liquid crystal composition according to claim 12, wherein the polymerizable compound in the liquid crystal composition is polymerized.

19. Use of the liquid crystal composition according to claim 1 for a liquid crystal display element.

20. Use of the liquid crystal composition according to claim 12 for a polymer-stabilized alignment type liquid crystal display element.

Technical Field

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

Background

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

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

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

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

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

Further, these liquid crystal display elements are required to have excellent display quality in which display defects such as image sticking and display unevenness are not generated or suppressed. To achieve this, the following attempts are made: various additives are added to a Liquid Crystal composition to improve the reliability of the entire Liquid Crystal Display (LCD) panel.

[ Prior art documents ]

[ patent document ]

[ patent document 1] Japanese patent laid-open No. 2016-94412

Disclosure of Invention

[ problems to be solved by the invention ]

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

[ means for solving problems ]

The present inventors have studied various liquid crystalline compounds and various chemical substances and have found that the above problems can be solved by using specific compounds, and have completed the present invention. That is, the present invention relates to a liquid crystal composition containing at least one compound selected from the compounds represented by formula (1) as an additive X and having a nematic phase and negative dielectric anisotropy, and a liquid crystal display element containing the same.

In the formula (1), R^aHydrogen, a group represented by the formula (F), an alkyl group having 1 to 30 carbon atoms, an alicyclic hydrocarbon group having 3 to 30 carbon atoms or an aromatic hydrocarbon group having 6 to 30 carbon atoms, at least one of the group consisting of an alkyl group, an alicyclic hydrocarbon group and an aromatic hydrocarbon group₂-may be substituted by-S-, -O-, -NH-or-CO-, at least one-CH₂-CH₂-may be substituted by-CH-or-C ≡ C-, of which groups at least one hydrogen may be substituted by halogen; r^bIs an alkyl group having 1 to 30 carbon atoms, an alicyclic hydrocarbon group having 3 to 30 carbon atoms or an aromatic hydrocarbon group having 6 to 30 carbon atoms, wherein at least one-CH group₂-may be substituted by-S-, -O-, -NH-or-CO-, at least one-CH₂-CH₂-may be substituted by-CH-or-C ≡ C-, of which groups at least one hydrogen may be substituted by halogen; z^aAnd Z^cIs a single bond or an alkylene group having 1 to 30 carbon atoms, in which at least one-CH group₂-may be substituted by-O-, -NH-or-CO-, at least one-CH₂-CH₂-may be substituted by-CH-or-C ≡ C-, at least one hydrogen may be substituted by halogen; z^bIs a single bond, an alkylene group having 1 to 30 carbon atoms, an alicyclic hydrocarbon group having 3 to 30 carbon atoms or an aromatic hydrocarbon group having 6 to 30 carbon atoms, wherein at least one-CH group₂-may be substituted by-S-, -O-, -NH-or-CO-, at least one-CH₂-CH₂-can-CH-or-C ≡ C-wherein at least one hydrogen may be substituted by halogen or a group represented by formula (F); s is sulfur; n is 0, 1,2, 3 or 4; p is 0 or 1;

in the formula (F), R^cIs an alkyl group having 1 to 30 carbon atoms, an alicyclic hydrocarbon group having 3 to 30 carbon atoms or an aromatic hydrocarbon group having 6 to 30 carbon atoms, wherein at least one-CH group₂-may be substituted by-S-, -O-, -NH-or-CO-, at least one-CH₂-CH₂-may be substituted by-CH-or-C ≡ C-, of which groups at least one hydrogen may be substituted by halogen; z^dIs a single bond or an alkylene group having 1 to 30 carbon atoms, in which at least one-CH group₂-may be substituted by-O-, -NH-or-CO-, at least one-CH₂-CH₂-may be substituted by-CH-or-C ≡ C-, at least one hydrogen may be substituted by halogen; s is sulfur; m is 0, 1,2, 3 or 4; r is 0 or 1.

[ Effect of the invention ]

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

Detailed Description

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

The liquid crystal composition is prepared by mixing a plurality of liquid crystalline compounds. An additive such as an optically active compound or a polymerizable compound is added to the liquid crystal composition as needed. Even in the case where an additive is added, the proportion of the liquid crystalline compound is represented by a mass percentage (mass%) based on the mass of the liquid crystal composition containing no additive. The proportion of the additive is represented by mass percentage (mass%) based on the mass of the liquid crystal composition containing no additive. That is, the ratio of the liquid crystalline compound or the additive is calculated based on the total mass of the liquid crystalline compound.

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

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

In formula (1z), for example, the expression "Ra and Rb are alkyl, alkoxy or alkenyl" means that Ra and Rb are independently selected from the group of alkyl, alkoxy and alkenyl. Here, the group represented by Ra and the group represented by Rb may be the same or may be different. The rules also apply to the case where the notation of Ra is used in a variety of compounds. The rules also apply to the case where multiple Ra's are used in one compound.

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

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

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

The same applies to divalent radicals such as tetrahydropyran-2, 5-diyl. Further, in order to raise the upper limit temperature, tetrahydropyran-2, 5-diyl (R) is preferred. The same applies to a bonding group (-COO-or-OCO-) such as carbonyloxy.

The present invention is as follows.

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

In the formula (1), R^aHydrogen, a group represented by the formula (F), an alkyl group having 1 to 30 carbon atoms, an alicyclic hydrocarbon group having 3 to 30 carbon atoms or an aromatic hydrocarbon group having 6 to 30 carbon atoms, at least one of the group consisting of an alkyl group, an alicyclic hydrocarbon group and an aromatic hydrocarbon group₂-may be substituted by-S-, -O-, -NH-or-CO-, at least one-CH₂-CH₂-may be substituted by-CH-or-C ≡ C-, of which groups at least one hydrogen may be substituted by halogen; r^bIs an alkyl group having 1 to 30 carbon atoms, an alicyclic hydrocarbon group having 3 to 30 carbon atoms or an aromatic hydrocarbon group having 6 to 30 carbon atoms, wherein at least one-CH group₂-may be substituted by-S-, -O-, -NH-or-CO-, at least one-CH₂-CH₂-may be substituted by-CH-or-C ≡ C-, of which groups at least one hydrogen may be substituted by halogen; z^aAnd Z^cIs a single bond or an alkylene group having 1 to 30 carbon atoms, in which at least one-CH group₂-may be substituted by-O-, -NH-or-CO-, at least one-CH₂-CH₂-may be substituted by-CH-or-C ≡ C-, at least one hydrogen may be substituted by halogen; z^bIs a single bond, an alkylene group having 1 to 30 carbon atoms, an alicyclic hydrocarbon group having 3 to 30 carbon atoms or an aromatic hydrocarbon group having 6 to 30 carbon atoms, wherein at least one-CH group₂-may be substituted by-S-, -O-, -NH-or-CO-, at least one-CH₂-CH₂-may be substituted by-CH-or-C ≡ C-, of which at least one hydrogen may be substituted by halogen or a group represented by formula (F); s is sulfur; n is 0, 1,2, 3 or 4; p is 0 or 1;

in the formula (F), R^cIs an alkyl group having 1 to 30 carbon atoms, an alicyclic hydrocarbon group having 3 to 30 carbon atoms or an aromatic hydrocarbon group having 6 to 30 carbon atoms, wherein at least one-CH group₂-may be substituted by-S-, -O-, -NH-or-CO-, at least one-CH₂-CH₂-may be substituted by-CH-or-C ≡ C-, of which groups at least one hydrogen may be substituted by halogen; z^dIs a single bond or an alkylene group having 1 to 30 carbon atoms, in which at least one-CH group₂-may be substituted by-O-, -NH-or-CO-, at least one-CH₂-CH₂-may be substituted by-CH-or-C ≡ C-, at least one hydrogen may be substituted by halogen; s is sulfur; m is 0, 1,2, 3 or 4; r is 0 or 1.

Item 2. the liquid crystal composition according to item 1, which contains at least one compound selected from the compounds represented by formulae (1-1) to (1-4) as an additive X.

In the formulae (1-1) to (1-4), R^fHydrogen, an alkyl group having 1 to 20 carbon atoms, an alicyclic hydrocarbon group having 3 to 20 carbon atoms or an aromatic hydrocarbon group having 6 to 20 carbon atoms, wherein at least one-CH group₂-may be substituted by-S-, -O-or-CO-, at least one-CH₂-CH₂-may be substituted by-CH ═ CH-; r^g、R^h、RⁱAnd R^jHydrogen, alkyl of 1 to 5 carbon atoms, at least one-CH of these groups₂-may be substituted by-O-or-CO-, at least one-CH₂-CH₂-may be substituted with-CH ═ CH-, at least one hydrogen may be substituted with a group represented by formula (F-1); r^dAnd R^eIs an alkyl group having 1 to 20 carbon atoms, an alicyclic hydrocarbon group having 3 to 20 carbon atoms or an aromatic hydrocarbon group having 6 to 20 carbon atoms, wherein at least one-CH group₂-may be substituted by-S-, -O-or-CO-, at least one-CH₂-CH₂-may be substituted by-CH ═ CH-; z^eAnd Z^fIs a single bond or an alkylene group having 1 to 10 carbon atoms, in which at least one-CH group₂-may be substituted by-O-, -NH-or-CO-, at least one-CH₂-CH₂-may be substituted by-CH ═ CH-; z^gIs alkylene with 1 to 6 carbon atoms, in which at least one-CH₂-may be substituted by-S-, -O-, -NH-or-CO-, at least one-CH₂-CH₂-may be substituted by-CH ═ CH-; s is sulfur; n is¹And n²Is 0, 1,2 or 3;

in the formula (F-1), R^jIs an alkyl group having 1 to 20 carbon atoms, an alicyclic hydrocarbon group having 3 to 20 carbon atoms or an aromatic hydrocarbon group having 6 to 20 carbon atoms, wherein at least one-CH group₂-may be substituted by-O-or-CO-, at least one-CH₂-CH₂-may be substituted by-CH ═ CH-; z^hIs a single bond or an alkylene group having 1 to 10 carbon atoms, in which at least one-CH group₂-may be substituted by-O-or-CO-; s is sulfur; m is¹Is 0, 1,2 or 3; r is¹Is 0 or 1.

Item 3. the liquid crystal composition according to item 1 or item 2, wherein the proportion of the additive X is in a range of 0.0001 to 2 mass%.

Item 4. the liquid crystal composition according to any one of item 1 to item 3, which contains at least one compound selected from the compounds represented by formula (2) as component A.

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

Item 5. the liquid crystal composition according to any one of item 1 to item 4, which contains at least one compound selected from the group consisting of the compounds represented by formulae (2-1) to (2-35) as the component A.

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

Item 6. the liquid crystal composition according to item 4 or 5, wherein the proportion of the component A is in the range of 10 to 90 mass%.

Item 7. the liquid crystal composition according to any one of item 1 to item 6, which contains at least one compound selected from the compounds represented by formula (3) as the component B.

In the formula (3), R^3aAnd R^3bIs alkyl group having 1 to 12 carbon atoms, alkoxy group having 1 to 12 carbon atoms, alkenyl group having 2 to 12 carbon atoms, or alkenyl group having 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^3aIs a single bond, ethylene, vinylidene, methyleneoxy or carbonyloxy; c is 1,2 or 3.

Item 8. the liquid crystal composition according to any one of item 1 to item 7, which contains at least one compound selected from the compounds represented by formulae (3-1) to (3-13) as the component B.

In formulae (3-1) to (3-13), R^3aAnd R^3bIs alkyl of carbon number 1 to 12, carbonAn alkoxy group having a number of 1 to 12, an alkenyl group having a carbon number of 2 to 12, or an alkenyl group having a carbon number of 2 to 12 in which at least one hydrogen is substituted with fluorine or chlorine.

Item 9. the liquid crystal composition of item 7 or 8, wherein the proportion of the component B is in the range of 10 to 90 mass%.

Item 10 the liquid crystal composition according to any one of item 1 to item 9, which contains at least one compound selected from polymerizable compounds represented by formula (4) as an additive Y.

In the formula (4), the ring F and the ring I are cyclohexyl, cyclohexenyl, phenyl, 1-naphthyl, 2-naphthyl, tetrahydropyran-2-yl, 1, 3-dioxane-2-yl, pyrimidin-2-yl or pyridin-2-yl, and in these rings, at least one hydrogen may be substituted with fluorine, chlorine, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or an alkyl group having 1 to 12 carbon atoms in which at least one hydrogen is substituted with fluorine or chlorine; ring G is 1, 4-cyclohexylene, 1, 4-cyclohexenylene, 1, 4-phenylene, naphthalene-1, 2-diyl, naphthalene-1, 3-diyl, naphthalene-1, 4-diyl, naphthalene-1, 5-diyl, naphthalene-1, 6-diyl, naphthalene-1, 7-diyl, naphthalene-1, 8-diyl, naphthalene-2, 3-diyl, naphthalene-2, 6-diyl, naphthalene-2, 7-diyl, tetrahydropyran-2, 5-diyl, 1, 3-dioxane-2, 5-diyl, pyrimidine-2, 5-diyl or pyridine-2, 5-diyl, and in these rings, at least one hydrogen may be substituted with fluorine, chlorine, an alkyl group having a carbon number of 1 to 12, an alkoxy group having a carbon number of 1 to 12, Or at least one hydrogen is substituted by a fluorine or chlorine substituted alkyl group of carbon number 1 to 12; z^4aAnd Z^4bIs a single bond or an alkylene group having 1 to 10 carbon atoms, in which at least one-CH group₂-may be substituted by-O-, -CO-, -COO-or-OCO-, at least one-CH₂-CH₂-may be via-CH ═ CH-, -C (CH)₃)＝CH-、-CH＝C(CH₃) -or-C (CH)₃)＝C(CH₃) -substitution, of which at least one hydrogen may be substituted by fluorine or chlorine; p^4a、P^4bAnd P^4cIs a polymerizable group; sp^4a、Sp^4bAnd Sp^4cIs a single bond or an alkylene group having 1 to 10 carbon atoms, of which at leastone-CH₂At least one-CH which may be substituted by-O-, -COO-, -OCO-or-OCOO-)₂-CH₂-may be substituted by-CH ═ CH-or-C ≡ C-, at least one of these groups being substituted by fluorine or chlorine; d is 0, 1 or 2; e. f and g are 0, 1,2, 3 or 4; and the sum of e, f and g is 1 or more.

Item 11 the liquid crystal composition of item 10, wherein, in formula (4), P^4a、P^4bAnd P^4cIs a group selected from the polymerizable groups represented by the formulae (P-1) to (P-5).

In the formulae (P-1) to (P-5), M¹、M²And M³Hydrogen, fluorine, an alkyl group having 1 to 5 carbon atoms, or an alkyl group having 1 to 5 carbon atoms in which at least one hydrogen is substituted with fluorine or chlorine.

Item 12. the liquid crystal composition according to any one of items 1 to 11, which contains at least one compound selected from polymerizable compounds represented by formulae (4-1) to (4-29) as an additive Y.

In formulae (4-1) to (4-29), Sp^4a、Sp^4bAnd Sp^4cIs a single bond or an alkylene group having 1 to 10 carbon atoms, in which at least one-CH group₂At least one-CH which may be substituted by-O-, -COO-, -OCO-or-OCOO-)₂-CH₂-may be substituted by-CH ═ CH-or-C ≡ C-, at least one of these groups being substituted by fluorine or chlorine; p^4d、P^4eAnd P^4fIs selected from those represented by the formulae (P-1) to (P-3)A polymerizable group of the above groups;

in the formulae (P-1) to (P-3), M¹、M²And M³Hydrogen, fluorine, an alkyl group having 1 to 5 carbon atoms, or an alkyl group having 1 to 5 carbon atoms in which at least one hydrogen is substituted with fluorine or chlorine.

Item 13. the liquid crystal composition of any one of items 10 to 12, wherein a proportion of the additive Y is in a range of 0.03 to 10 mass%.

Item 14. a liquid crystal display element containing the liquid crystal composition according to any one of items 1 to 13.

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

Item 16. a polymer stable alignment type liquid crystal display element, which contains the liquid crystal composition according to any one of items 10 to 13, and in which a polymerizable compound is polymerized.

Item 17. use of a liquid crystal composition according to any one of item 1 to item 13 in a liquid crystal display element.

Item 18. use of a liquid crystal composition according to any one of item 10 to item 13 in a liquid crystal display element of a polymer-stabilized alignment type.

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

The composition of the present invention is illustrated in the following order. First, the composition of the component compounds in the composition will be described. Secondly, the main characteristics of the component compounds and the main effects of the compounds on the composition will be described. Third, the combination of the component compounds in the composition, the preferable ratio of the component compounds, and the basis thereof will be explained. Fourth, preferred embodiments of the component compounds will be described. Fifth, preferred component compounds are shown. Sixth, additives that can be added to the composition will be described. Seventh, a method for synthesizing the component compound will be explained. Finally, the use of the composition is illustrated.

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

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

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

TABLE 2 Properties of liquid crystalline Compounds

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

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

The main effects of the component compounds are as follows. The additive X functions as an antioxidant and contributes to high stability against heat or light. Since the compound (1) is added in a small amount, it does not affect the characteristics such as the upper limit temperature, the optical anisotropy and the dielectric anisotropy in many cases. The compound (2) increases the dielectric anisotropy and lowers the lower limit temperature. The compound (3) lowers the viscosity or raises the upper limit temperature. Since the compound (4) is polymerizable, it forms a polymer by polymerization. The polymer stabilizes the orientation of liquid crystal molecules, and thus shortens the response time of the element.

The organic compound is deteriorated by light or thermal energy and generates radicals. The radicals act as chain carriers, and further react with other organic compounds and the like to generate new radicals, which are then linked. In addition, when the reaction is carried out, a peroxide is generated, and a new radical is also generated from the peroxide and is carried in the chain. A compound having an action of stopping such radical chain is called a radical chain inhibitor (primary antioxidant). Phenol antioxidants such as 2, 6-di-tert-butyl-4-methylphenol are used as ordinary primary antioxidants, and supply hydrogen in the phenol portion to radicals, and they themselves become phenoxy radicals having low activity due to steric hindrance and the like. Then, the radical is trapped and stabilized. The increase of the free radicals is suppressed by the action. On the other hand, with respect to the peroxide generated during the deterioration, the peroxide is decomposed to form an inert compound, thereby suppressing the loading of the generated radical to the chain. Such an agent is called a peroxide decomposer (secondary antioxidant), and a sulfur-based antioxidant (thioether compound), a phosphorus-based antioxidant (phosphite compound), or the like is generally used.

The additive X of the present invention is at least one compound selected from the compounds represented by the formula (1). The OH group of the compound is converted into a phenoxy radical to capture the radical, thereby exhibiting a high antioxidant effect. In addition, sulfur (S) contained in the structure of the compound also acts as a peroxide decomposer.

Third, the combination of the component compounds in the composition, the preferable ratio of the component compounds, and the basis thereof will be explained. Preferred combinations of the component compounds in the composition are compound (1) + compound (2), compound (1) + compound (3), compound (1) + compound (2) + compound (4), compound (1) + compound (3) + compound (4), or compound (1) + compound (2) + compound (3) + compound (4). Further preferred combinations are compound (1) + compound (2) + compound (3) or compound (1) + compound (2) + compound (3) + compound (4).

The preferable proportion of the additive X is 0.0001% by mass or more, and the preferable proportion of the additive X is about 2.0000% by mass or less in order to lower the lower limit temperature. Further, the preferable ratio is in the range of about 0.0050 to about 1.0000 mass%. A particularly preferred ratio is in the range of about 0.0100% to about 0.1000% by mass.

The preferable proportion of the compound (2) is about 10% by mass or more for improving the dielectric anisotropy, and the preferable proportion of the compound (2) is about 90% by mass or less for lowering the lower limit temperature. Further, the preferable ratio is in the range of about 20 to about 80 mass%. A particularly preferred ratio is in the range of about 30% by mass to about 70% by mass.

The preferable proportion of the compound (3) is about 10% by mass or more in order to increase the upper limit temperature or to decrease the viscosity, and the preferable proportion of the compound (3) is about 90% by mass or less in order to increase the dielectric anisotropy. Further, the preferable ratio is in the range of about 20 to about 80 mass%. A particularly preferred ratio is in the range of about 30% by mass to about 70% by mass.

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

Fourth, preferred embodiments of the component compounds will be described. In the formula (1), R^aHydrogen, a group represented by the formula (F), an alkyl group having 1 to 30 carbon atoms, an alicyclic hydrocarbon group having 3 to 30 carbon atoms or an aromatic hydrocarbon group having 6 to 30 carbon atoms, at least one of the group consisting of an alkyl group, an alicyclic hydrocarbon group and an aromatic hydrocarbon group₂-may be substituted by-S-, -O-, -NH-or-CO-, at least one-CH₂-CH₂-may be substituted by-CH-or-C ≡ C-, of which groups at least one hydrogen may be substituted by halogen. Preferred R^aHydrogen, a group represented by the formula (F), an alkyl group having 1 to 15 carbon atoms, and at least one-CH₂-may be substituted by-S-, -O-or-CO-, at least one-CH₂-CH₂-may be substituted by-CH ═ CH-. R^bIs an alkyl group having 1 to 30 carbon atoms, an alicyclic hydrocarbon group having 3 to 30 carbon atoms or an aromatic hydrocarbon group having 6 to 30 carbon atoms, wherein at least one-CH group₂-may be substituted by-S-, -O-, -NH-or-CO-, at least one-CH₂-CH₂-may be substituted by-CH-or-C ≡ C-, of which groups at least one hydrogen may be substituted by halogen. Preferred R^bIs alkyl of carbon number 1 to 15, at least one-CH₂-may be substituted by-S-, -O-or-CO-, at least one-CH₂-CH₂-may be substituted by-CH ═ CH-. Z^aAnd Z^cIs a single bond or an alkylene group having 1 to 30 carbon atoms, in which at least one-CH group₂-may be substituted by-O-, -NH-or-CO-, at least one-CH₂-CH₂-may be substituted by-CH-or-C ≡ C-, at least one hydrogen may be substituted by halogen. Preferred Z^aOr Z^cIs a single bond or alkylene having 1 to 10 carbon atomsIn the alkylene group, at least one-CH₂-may be substituted by-O-or-CO-. Z^bIs a single bond, an alkylene group having 1 to 30 carbon atoms, an alicyclic hydrocarbon group having 3 to 30 carbon atoms or an aromatic hydrocarbon group having 6 to 30 carbon atoms, wherein at least one-CH group₂-may be substituted by-S-, -O-, -NH-or-CO-, at least one-CH₂-CH₂-may be substituted by-CH ═ CH-or-C ≡ C-, at least one of these groups may be substituted by halogen or a group represented by formula (F). Preferred Z^bIs a single bond, alkylene group of 1 to 30 carbon atoms, at least one of these groups being-CH₂-may be substituted by-S-, -O-or-CO-, at least one-CH₂-CH₂-may be substituted with-CH ═ CH-, and at least one hydrogen may be substituted with a group represented by formula (F). S is sulfur. n is 0, 1,2, 3 or 4. Preferably n is 2. p is 0 or 1.

In the formula (F), R^cIs an alkyl group having 1 to 30 carbon atoms, an alicyclic hydrocarbon group having 3 to 30 carbon atoms or an aromatic hydrocarbon group having 6 to 30 carbon atoms, wherein at least one-CH group₂-may be substituted by-S-, -O-, -NH-or-CO-, at least one-CH₂-CH₂-may be substituted by-CH-or-C ≡ C-, of which groups at least one hydrogen may be substituted by halogen. Preferred R^cIs an alkyl group having 1 to 15 carbon atoms, of which at least one-CH group₂-may be substituted by-S-, -O-or-CO-, at least one-CH₂-CH₂-may be substituted by-CH ═ CH-. Z^dIs a single bond or an alkylene group having 1 to 30 carbon atoms, in which at least one-CH group₂-may be substituted by-O-, -NH-or-CO-, at least one-CH₂-CH₂-may be substituted by-CH-or-C ≡ C-, at least one hydrogen may be substituted by halogen. Preferred Z^dIs a single bond or an alkylene group having 1 to 10 carbon atoms, in which at least one-CH group₂-may be substituted by-O-or-CO-. S is sulfur. m is 0, 1,2, 3 or 4. Preferably m is 2. r is 0 or 1.

In the formulae (1-1) to (1-4), R^fHydrogen, an alkyl group having 1 to 20 carbon atoms, an alicyclic hydrocarbon group having 3 to 20 carbon atoms or an aromatic hydrocarbon group having 6 to 20 carbon atoms, wherein at least one-CH group₂-may be substituted by-S-, -O-or-CO-, at least one-CH₂-CH₂-may be via-CH ═ CH-substitution. Preferred R^fIs hydrogen, alkyl of carbon number 1 to 15, at least one-CH₂-may be substituted by-O-or-CO-. R^g、R^h、RⁱAnd R^jHydrogen, alkyl of 1 to 5 carbon atoms, at least one-CH of these groups₂-may be substituted by-O-or-CO-, at least one-CH₂-CH₂-may be substituted with-CH ═ CH-, and at least one hydrogen may be substituted with a group represented by formula (F-1). Preferred R^g、R^h、RⁱOr R^jIs an alkyl group having 1 to 5 carbon atoms, at least one of these groups being-CH₂-may be substituted by-O-or-CO-. R^dAnd R^eIs an alkyl group having 1 to 20 carbon atoms, an alicyclic hydrocarbon group having 3 to 20 carbon atoms or an aromatic hydrocarbon group having 6 to 20 carbon atoms, wherein at least one-CH group₂-may be substituted by-S-, -O-or-CO-, at least one-CH₂-CH₂-may be substituted by-CH ═ CH-. Preferred R^dOr R^eIs an alkyl group having 1 to 15 carbon atoms, of which at least one-CH group₂-may be substituted by-S-, -O-or-CO-. Z^eAnd Z^fIs a single bond or an alkylene group having 1 to 10 carbon atoms, in which at least one-CH group₂-may be substituted by-O-, -NH-or-CO-, at least one-CH₂-CH₂-may be substituted by-CH ═ CH-. Preferred Z^eOr Z^fIs a single bond or an alkylene group having 1 to 5 carbon atoms, in which at least one-CH group₂-may be substituted by-O-or-CO-. Z^gIs alkylene with 1 to 6 carbon atoms, in which at least one-CH₂-may be substituted by-S-, -O-, -NH-or-CO-, at least one-CH₂-CH₂-may be substituted by-CH ═ CH-. Preferred Z^gIs alkylene with 1 to 5 carbon atoms, in which at least one-CH₂-may be substituted by-O-or-CO-. S is sulfur. n is¹And n²Is 0, 1,2 or 3. Preferred n is¹Or n²Is 2.

In the formula (F-1), R^jIs an alkyl group having 1 to 20 carbon atoms, an alicyclic hydrocarbon group having 3 to 20 carbon atoms or an aromatic hydrocarbon group having 6 to 20 carbon atoms, wherein at least one-CH group₂-may be substituted by-O-or-CO-, at least one-CH₂-CH₂-may be substituted by-CH ═ CH-. Superior foodSelected R^jIs an alkyl group having 1 to 15 carbon atoms, of which at least one-CH group₂-may be substituted by-O-or-CO-. Z^hIs a single bond or an alkylene group having 1 to 10 carbon atoms, in which at least one-CH group₂-may be substituted by-O-or-CO-. Preferred Z^hIs a single bond or an alkylene group having 1 to 5 carbon atoms, in which at least one-CH group₂-may be substituted by-O-or-CO-. m is¹Is 0, 1,2 or 3. Preferred m¹Is 2. r is¹Is 0 or 1.

Representative examples of the additive X include compounds represented by the formulae (1-A) to (1-J), but the present invention is not limited to these.

In the formulae (2) and (3), R^2aAnd R^2bIs hydrogen, alkyl group having 1 to 12 carbon atoms, alkoxy group having 1 to 12 carbon atoms, alkenyl group having 2 to 12 carbon atoms, alkenyloxy group having 2 to 12 carbon atoms, or alkyl group having 1 to 12 carbon atoms wherein at least one hydrogen is substituted with fluorine or chlorine. For improved stability, R is preferred^2aOr R^2bIs an alkyl group having 1 to 12 carbon atoms, and R is preferably selected to improve dielectric anisotropy^2aOr R^2bIs alkoxy with 1 to 12 carbon atoms. R^3aAnd R^3bIs 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 is substituted with fluorine or chlorine. Preferred R for reducing viscosity^3aOr R^3bAn alkenyl group having 2 to 12 carbon atoms, and R is preferably selected for the purpose of improving stability^3aOr R^3bIs an alkyl group having 1 to 12 carbon atoms.

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

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

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

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

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

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

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

or

Preferably:

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

The preferred ring B is 2, 3-difluoro-1, 4-phenylene for decreasing viscosity, 2-chloro-3-fluoro-1, 4-phenylene for decreasing optical anisotropy, and 7, 8-difluorochroman-2, 6-diyl for increasing dielectric anisotropy.

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

Z^2aAnd Z^2bIs a single bond, ethylene, vinylidene, methyleneoxy or carbonyloxy. For reducing the viscosity, preferred is Z^2aOr Z^2bIs a single bond, and Z is preferably Z for lowering the lower limit temperature^2aOr Z^2bIs ethylene, and Z is preferably selected to improve the dielectric anisotropy^2aOr Z^2bIs methyleneoxy. Z^3aIs a single bond, ethylene, vinylidene, methyleneoxy or carbonyloxy. For reducing the viscosity, preferred is Z^3aIs a single bond.

In the methyleneoxy group, -CH₂O-is superior to-OCH₂-. In the carbonyloxy group, -COO-is preferable to-OCO-.

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

In the formula (4), P^4a、P^4bAnd P^4cIs a polymerizable group. Preferred P^4a、P^4bOr P^4cIs a polymerizable group selected from the group represented by the formulae (P-1) to (P-5). Further preferred is P^4a、P^4bOr P^4cIs represented by formula (P-1) or formula (P-2). Particularly preferred formula (P-1) is-OCO-CH ═ CH₂or-OCO-C (CH)₃)＝CH₂. The wavy lines of the formulae (P-1) to (P-5) indicate the sites of bonding.

In the formulae (P-1) to (P-5), M¹、M²And M³Hydrogen, fluorine, an alkyl group having 1 to 5 carbon atoms, or an alkyl group having 1 to 5 carbon atoms in which at least one hydrogen is substituted with fluorine or chlorine. For the purpose of enhancing reactivity, M is preferred¹、M²Or M³Is hydrogen or methyl. Further preferred is M¹Is methyl, more preferably M²Or M³Is hydrogen.

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

In the formula (4), Sp^4a、Sp^4bAnd Sp^4cIs a single bond or an alkylene group having 1 to 10 carbon atoms, in which at least one-CH group₂At least one-CH which may be substituted by-O-, -COO-, -OCO-or-OCOO-)₂-CH₂-may be substituted by-CH ═ CH-or-C ≡ C-, at least one of these groups being substituted by fluorine or chlorine. Preferred is Sp^4a、Sp^4bOr Sp^4cIs a single bond, -CH₂CH₂-、-CH₂O-、-OCH₂-, -COO-, -OCO-, -CO-CH-or-CH-CO-. Further preferred is Sp^4a、Sp^4bOr Sp^4cIs a single bond.

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

Z^4aAnd Z^4bIs a single bond or an alkylene group having 1 to 10 carbon atoms, wherein,at least one-CH₂-may be substituted by-O-, -CO-, -COO-or-OCO-, at least one-CH₂-CH₂-may be via-CH ═ CH-, -C (CH)₃)＝CH-、-CH＝C(CH₃) -or-C (CH)₃)＝C(CH₃) -substitution, of which at least one hydrogen may be substituted by fluorine or chlorine. Preferred Z^4aOr Z^4bIs a single bond, -CH₂CH₂-、-CH₂O-、-OCH₂-, -COO-or-OCO-. Further preferred is Z^4aOr Z^4bIs a single bond.

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

Fifth, preferred component compounds are shown. Preferred compounds (1) are the compounds (1-1) to (1-4) described in the item 2. Among these compounds, the compound (1-2) or the compound (1-3) is preferable.

Preferred compound (2) is the compound (2-1) to the compound (2-35) described in the item 5. Of these compounds, it is preferable that at least one of the components A is the compound (2-1), the compound (2-3), the compound (2-6), the compound (2-8), the compound (2-10), the compound (2-14) or the compound (2-16). Preferably, at least two of the components A are a combination of the compounds (2-1) and (2-8), the compounds (2-1) and (2-14), the compounds (2-3) and (2-8), the compounds (2-3) and (2-14), the compounds (2-3) and (2-16), the compounds (2-6) and (2-8), the compounds (2-6) and (2-10), the compounds (2-6) and (2-16), the compounds (2-10) and (2-16).

Preferred compound (3) is the compound (3-1) to the compound (3-13) described in the item 8. Of these compounds, it is preferable that at least one of the components B is the compound (3-1), the compound (3-3), the compound (3-5), the compound (3-6), the compound (3-8) or the compound (3-9). Preferably, at least two of the components B are a combination of the compound (3-1) and the compound (3-3), the compound (3-1) and the compound (3-5), or the compound (3-1) and the compound (3-6).

Preferred compound (4) is the compound (4-1) to the compound (4-29) described in the item 12. Of these compounds, it is preferable that at least one of the additives Y is the compound (4-1), the compound (4-2), the compound (4-24), the compound (4-25), the compound (4-26) or the compound (4-27). Preferably, at least two of the additives Y are a combination of the compound (4-1) and the compound (4-2), the compound (4-1) and the compound (4-18), the compound (4-2) and the compound (4-24), the compound (4-2) and the compound (4-25), the compound (4-2) and the compound (4-26), the compound (4-25) and the compound (4-26), or the compound (4-18) and the compound (4-24).

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

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

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

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

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

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

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

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

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

Seventh, a method for synthesizing the component compound will be explained. These compounds can be synthesized by known methods. A synthesis method is exemplified. Compound (1-a) is yilujianuo (Irganox)1520L (registered trademark; BASF), and compound (1-B) is yilujianuo (Irganox)1726 (registered trademark; BASF), available from BASF. The compound (1-C) and the compound (1-D) can be obtained from Tokyo Chemical Industry (TCI). The compound (1-E) is generally known as a pharmaceutical product called Probucol (Probucol) and is available from Tokyo Chemical Industry (TCI). The compound (1-F) can be obtained from Tokyo Chemical Industry (TCI). The compound (2-1) is synthesized by the method described in Japanese patent laid-open No. 2000-053602. The compound (3-1) is synthesized by the method described in Japanese patent laid-open publication No. 59-176221. The compound (4-18) is synthesized by the method described in Japanese patent laid-open No. Hei 7-101900. Antioxidants are commercially available. Compound (6-1) is available from Sigma Aldrich Corporation. The compound (6-2) and the like are synthesized by the method described in the specification of U.S. Pat. No. 3660505.

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

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

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