JP2001192660A - Liquid crystal composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a liquid crystal composition satisfying various characteristics required for electrooptical display element, having a wide nematic temperature range, a low viscosity, excellent high-speed responsiveness and a low threshold voltage, capable of maintaining a high voltage retention up to a high temperature and a liquid crystal display element using the liquid crystal composition or a liquid crystal composition and liquid crystal display elements (TN, STN and AM-LCD) having more improved defects than those of conventional liquid crystal composition and liquid crystal display elements. SOLUTION: This liquid crystal composition contains a first component of general formula (I) and a second component of general formula (II). The liquid crystal display elements use the liquid crystal composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a nematic liquid crystal medium useful as an electro-optical liquid crystal display material, and a liquid crystal display device using the same.

[0002]

2. Description of the Related Art Since liquid crystal displays (LCDs) have appeared as calculator displays, they have progressed from computer development to TN-LCDs (twisted nematic liquid crystal displays) to STN-LCDs. It has responded to the expansion of capacity. STN-L
CDs include Scheffer and others [SID '85 Digest, 120
(1985)] or Kinukawa et al. [SID '86 Digest, 122
Page (1986)], a word processor,
It has begun to spread widely to displays for high information processing such as personal computers. In particular, an active matrix liquid crystal display device (AM-LCD) with a thin film transistor attached to each pixel
Is expected to be the most promising display with high image quality that can be replaced by CRT and backed by flattening and energy saving.

In the AM-LCD, to increase the contrast,
A voltage is supplied to each pixel by attaching a switching element such as a thin film transistor or a diode to each pixel.

The AM-LCD differs from the TN and STN passive drive systems in that each pixel passes through a switching element for several tens of milliseconds.
It is driven by supplying a charge every time. For this reason, if the given charge cannot be completely held until the next writing time several tens of milliseconds after the supply of the charge, the display deteriorates. When the charge escapes, the potential between the electrodes decreases, the transmitted light intensity changes, and the contrast decreases. For this reason, a high voltage holding characteristic is required in the AM-LCD. In order to obtain a high voltage holding characteristic, it is necessary to select and use a material that easily maintains a high specific resistance for the liquid crystal composition for AM-LCD.

[0005] In recent years, the demand for notebook computers intended for portable use has been increased, and there has been an increasing demand for a wide operating temperature range that allows outdoor use and low power consumption that enables long-time battery operation. For low power consumption, a liquid crystal composition with a low threshold voltage that can be driven at a low voltage is required. In order to lower the threshold voltage, a material that increases the dielectric anisotropy Δε is required. However, in a system having a large dielectric anisotropy, the viscosity increases, the response is deteriorated, and the surroundings are deteriorated. There is a problem that it is difficult to maintain a high resistance because it is easily affected by contamination. For this reason, liquid crystal compositions for liquid crystal display devices such as TN, STN, and AM-LCD include (1) a wide liquid crystal temperature range that can be used outdoors (2) stability that can be used even at high temperatures (3) low threshold voltage ( 4) High voltage holding ratio (5) There is a need for a Δn that can be adjusted in order to prevent coloring and obtain optimal contrast with a wide viewing angle.

Conventional liquid crystal compositions cannot always meet these demands, and have exhibited a decrease in contrast due to a decrease in voltage holding ratio at high temperatures, crystal precipitation at low temperatures, and the appearance of a smectic phase. In addition, when left outdoors at high temperatures or under exposure to UV light or sunlight, the retention rate decreased and display defects were observed.

That is, a high nematic-isotropic transition temperature, a low crystal (or smectic)
There has been no liquid crystal composition or liquid crystal display element that simultaneously satisfies a transition temperature, a low threshold voltage capable of driving at a low voltage, a low viscosity enabling high-speed response, and a high voltage holding ratio at a high temperature. For example, WO9403558 discloses an example of a liquid crystal composition using a trifluoro compound and a difluoro compound, but has many problems such as a narrow liquid crystal temperature range and a high threshold voltage. Is the current situation.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to satisfy various characteristics required for an electro-optical display device, in particular, the above-mentioned liquid crystal display device, have a low threshold voltage, a wide nematic temperature range, and a low viscosity. With high-speed response,
Provided is a liquid crystal composition capable of maintaining a high voltage holding ratio up to a high temperature and a liquid crystal display device using the same, or a liquid crystal composition and a liquid crystal display device in which the above-mentioned drawbacks have been improved compared to the prior art.
(TN, STN, AM-LCD).

[0009]

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention has examined the liquid crystal compositions using various liquid crystal compounds, and has found the following liquid crystal compositions.

Invention 1 A liquid crystal medium based on a mixture of polar compounds having a positive dielectric anisotropy, which comprises a compound of the general formula (I)

[0011]

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(Wherein R ¹ is an alkyl group having 1 to 15 carbon atoms or an alkenyl group having 2 to 15 carbon atoms, and this group is unsubstituted or has at least one halogen as a substituent. And one or more CH ₂ groups present in each of these groups independently represent -O-, -S-, -CO-, -COO
-, -OCO-, and -OCO-O- may be substituted. Y
¹ is -F, -Cl, -CF ₃ , -OCF ₃ , -OCHF ₂ , -OCH ₂ F, -CN, R ¹
Same definition or formula (I-1)

Embedded image (Wherein X ³ and X ⁴ are each independently H, F or Cl, Q ¹ is -OCH _2- , -OCF _2- , -OCHF-, -CF ₂ -or a single bond, and Y ² Is F, Cl or CN). Ring A and Ring B
Are each independently a (a) trans-1,4-cyclohexylene group (in which one CH ₂ group or two or more non-adjacent CH ₂ groups are -O- and / or may be replaced -S- in) (b) 1,4-phenylene group (one more CH ₂ groups not CH ₂ group or adjacent that present in the group replaced by -N- (C) 1,4-cyclohexenylene, 1,4-bicyclo (2.2.2) octylene, piperidine-1,4-diyl, naphthalene-2,6-diyl, decahydronaphthalene-2, 6-diyl and 1,2,3,4-
Tetrahydronaphthalene-2,6-diyl (d) a group selected from the group consisting of a single bond,
(a), group (b) and group (c) may be substituted with CN or halogen, but when ring B represents a single bond, Y ¹ represents formula (I-1). L ¹ and L ² are each independently -COO-, -OCO-, -C
H ₂ O-, -OCH _2- , -CH ₂ CH _2- , -CH = CH-, -C≡C-,-(CH ₂ )
_{4 -, - CH = CH-} CH 2 CH 2 -, - a CH ₂ CH ₂ -CH = CH- or a single bond, but X ^1, X ² is H or F, X ¹ and X ² are different ,
m is 0 to 2. One or two compounds selected from
Containing more than one species, and further having the general formula (II)

[0013]

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Wherein R ² is independently of each other as defined for R ¹ in formula (I), and ring C and ring D are each independently of each other: (d) trans-1,4- cyclohexylene (one more CH ₂ groups not CH ₂ group or adjacent the present in this group may be replaced by -O- and or -S-) (e) 1, 4-phenylene group (one more CH ₂ groups not CH ₂ group or adjacent the present in this group may be replaced by-N-) (f) 1,4-cyclohexenylene , 1,4-bicyclo (2.2.2) octylene, piperidine-1,4-diyl, naphthalene-2,6-diyl, 1,2,3,4-tetrahydronaphthalene-2,6-diyl and decahydronaphthalene- A group selected from the group consisting of 2,6-diyl, the group (d), the group (e), the group (f) may be substituted with CN or halogen, 1,2,3, 4-tetrahydronaphthalene-2,6-diyl Are substituted or substituted by at least two or more halogens, L ³ and L ⁴ are each independently of each other L in the formula (1)
¹ and L ² have the same definition, X ⁵ and X ⁶ are each independently H or F, n is 0, 1 or 2, and Y ³ is-
F, -Cl or -CN, and Q ² is a single bond, -CF _2- , -OCF
₂ -or -OCHF-. A liquid crystal medium comprising one or more compounds of the above).

Invention 2 The liquid crystal medium according to Invention 1, comprising at least two or more compounds of the general formula (I). Invention 3 The liquid crystal medium according to Invention 1 or 2, wherein the content of the compound of the general formula (I) is in the range of 5 to 40% by mass. Invention 4 The liquid crystal medium according to any one of Inventions 1 to 3, comprising at least two or more compounds of the general formula (II).

Invention 5 As a compound of the general formula (II), a compound of the general formula (II-a)

[0017]

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(Wherein R ² has the same meaning as in formula (II), and L ⁵ and L ⁶ each independently represent -CH ₂ CH _2- , -CH =
CH-, -C≡C-,-(CH ₂ ) ₄ -or a single bond; ring D is 1,
Represents a 4-phenylene group or a trans-1,4-cyclohexylene group, X ⁶ represents H or F, n represents 0 or 1, Y ⁴ is F, -Cl, -CF ₃ , -OCF ₃ or Represents -OCHF ₂ . 5. The liquid crystal medium according to any one of the inventions 1 to 4, wherein the liquid crystal medium comprises the compound of (1).

Invention 6 As a compound of the general formula (II), a compound of the general formula (II-b)

[0020]

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(Wherein R ² has the same meaning as in formula (II), and L ⁵ and L ⁶ each independently represent -COO-, -OCO-,
-CH ₂ O-, -OCH _2- , -CH ₂ CH _2- , -CH = CH-, -C≡C-,-(CH ₂ ) ₄
-Or a single bond, wherein ring C and ring D are each independently
Represents a 1,4-phenylene group or a trans-1,4-cyclohexylene group, X ⁵ and X ⁶ each independently represent H or F, and Y ⁴ represents F, -Cl, -CF ₃ , -OCF ₃ , it represents a -CN or -OCHF _2. 6. The liquid crystal medium according to any one of Inventions 1 to 5, wherein the liquid crystal medium comprises the compound of the invention.

Invention 7 The liquid crystal medium according to any one of Inventions 1 to 6, comprising at least two compounds of the formula (II-a). Invention 8 The liquid crystal medium according to any one of Inventions 1 to 7, wherein the liquid crystal medium contains at least two or more compounds of the general formula (II-b). Invention 9 The content of the general formula (I) is in the range of 5 to 40% by mass, and the content of the general formula (II), the general formula (II-a), and the general formula (II-b) is 5 to 95% by mass. %. The liquid crystal composition according to any one of Inventions 1 to 8, wherein

Invention 10 In addition to general formulas (I) and (II), general formula (III)

[0024]

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(Wherein R ³ and R ⁴ are each independently an alkyl or alkoxyl group having 1 to 16 carbon atoms, which may be substituted by fluorine, an alkenyl group having 2 to 16 carbon atoms, 3-16 alkenyloxy group, or represents an alkyl group having 1 to 12 carbon atoms substituted with an alkoxyl group having 1 to 10 carbon atoms, and ring F, ring G and ring H are each independently a fluorine atom 1, which may be substituted
4-phenylene group, 2-methyl-1,4-phenylene group, 3-methyl-1,4-phenylene group, naphthalene-2,6-diyl group, phenanthrene-2,7-diyl group, fluorene-2,7 -Diyl group,
Trans-1,4-cyclohexylene group, 1,2,3,4-tetrahydronaphthalene-2,6-diyl group, decahydronaphthalene-
2,6-diyl group, trans-1,3-dioxane-2,5-diyl group, pyridine-2,5-diyl group, pyrimidine-2,5-diyl group, pyrazine-2,5-diyl group or pyridazine represents a 2,5-diyl group, o is 0, 1 or 2, L ⁷ and L ⁸ are each independently a single _{bond, -CH 2 CH 2 -, -} (CH 2) 4 -, - OCH _2- , -CH
₂ Represents O- or -C≡C-. ), At least 1
10. The liquid crystal medium according to any one of Inventions 1 to 9, wherein the liquid crystal medium includes a compound of the type described above.

Invention 11 As the compound of the general formula (III), a compound of the general formula (III-a)

[0027]

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(Wherein R ³ and R ⁴ have the same meanings as in formula (III), ring H represents a 1,4-phenylene group or trans-1,4-cyclohexylene group, and o represents 0 or The liquid crystal medium according to invention 10, comprising a compound represented by formula (1).

Invention 12 The liquid crystal medium according to any one of Inventions 1 to 11, wherein the compound of the general formula (I) contains at least one compound selected from the following formulas (Ia) to (Ie).

[0030]

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(Wherein R ¹ , X ¹ , X ² , X ³ , X ⁴ , Q ¹ and Y ² have the same meanings as in the general formula (I)) Invention 13 General formula (III) or general formula The invention characterized in that the content of the compound (III-a) is in the range of 5 to 95% by mass.
13. The liquid crystal medium according to 10 to 12.

Invention 14 As the general formula (II) or (II-a),

[0033]

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Wherein R ⁵ represents one or more compounds selected from the group consisting of an alkyl group having 1 to 16 carbon atoms and an alkenyl group having 2 to 8 carbon atoms. Invention 1 characterized in that the ratio is in the range of 5 to 40% by mass.
A liquid crystal medium according to any one of claims 13 to 13.

Invention 15 As formula (II) or (II-a), formula (II-d)

[0036]

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(Wherein R ⁵ represents an alkyl group having 1 to 16 carbon atoms or an alkenyl group having 2 to 8 carbon atoms), and contains at least one compound selected from the group consisting of Inventions 1-1, wherein is in the range of 5 to 40% by mass.
The liquid crystal medium according to 4.

Invention 16 General formula (III) or general formula (III-
The compound of the general formula (III-b)

[0039]

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(In the formula, R ⁶ and R ⁷ each independently represent an alkyl group having 1 to 8 carbon atoms or an alkenyl group having 2 to 8 carbon atoms.) Containing a compound, the content of which is in the range of 5 to 40% by mass, and further represented by the general formula (III-c)

[0041]

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(In the formula, R ⁸ and R ⁹ each independently represent an alkyl group having 1 to 8 carbon atoms or an alkenyl group having 2 to 8 carbon atoms.) 16. The liquid crystal medium according to any one of Inventions 10 to 15, wherein the liquid crystal medium contains a compound and the content thereof is in a range of 5 to 60% by mass.

Invention 17 The compound of the general formula (I) or the general formula (Ia) contains one or more compounds, and the content thereof is 5%.
In the range of about 40% by mass to the general formulas (II) and (II-
a) or contains one or more compounds of the general formula (II-b), the content of which is in the range of 5 to 40% by mass, and the general formula (III), the general formula (III-a) Containing one or two or more compounds of the general formula (III-b) or the general formula (III-c), wherein the content thereof is in the range of 5 to 60% by mass of the invention 1 to 16. The liquid crystal medium according to item 16.

Invention 18 General Formula (I-1)

[0045]

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(Wherein R ¹ represents an alkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, and ring A represents 1,4-phenylene group or trans-1,4-cyclohexylene group. L ¹ represents —CH ₂ CH ₂ — or a single bond; X ¹ and X ² represent H
Or represents F, X ¹ and X ² are different, X ³ and X ⁴ each independently represent H or F, m represents 0 or 1, Y ⁵ is -F, -CF ₃ , Represents -OCF ₃ , -OCHF ₂ , -OCH ₂ F, and -CN. ).

The general formula (I-1) is represented by the general formula (I-1a)

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(Wherein R ¹ , ring A, L ¹ and m have the same meaning as in formula (I-1)). General formula (I-1
a) MEC reagent, F-TEDA-BF4 (1-chloromethyl-4-fluoro-
Reaction of a fluorinating agent such as 1,4-diazoniumbicyclo [2,2,2] octanebis (tetrafluoroborate) with the general formula
A mixture of (I-1b) and the general formula (I-1c)

[0049]

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(Wherein R ¹ , ring A, L ¹ , and m have the same meaning as in formula (I-1)). These are isolated, trifluoromethanesulfonic acid ester general formula (I-1d)

[0051]

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(Wherein R ¹ , ring A, L ¹ , m, X ¹ and X ² represent the general formula (I-
Represents the same meaning as 1). ), And then the general formula (I-1e)

Embedded image (X ³ , X ⁴ , and Y ⁵ have the same meaning as in the general formula (I-1), and M represents a metal atom such as magnesium, lithium, and zinc.) In the presence of a transition metal catalyst such as palladium. By this, general formula (I-1) can be produced.

Invention 19 A liquid crystal medium according to any one of Inventions 1 to 17, which comprises Formula (I-1). Invention 20 A liquid crystal display device using the liquid crystal medium according to Inventions 1 to 17 and 19. Invention 21 A super-twisted nematic (STN) liquid crystal display device having a twist angle of 220 ° to 270 °, using the liquid crystal compositions according to Inventions 1 to 17 and Invention 19. Invention 22 An active matrix (AM) liquid crystal display device using the liquid crystal medium according to any one of Inventions 1 to 17 and Invention 19.

[0054]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of the present invention will be described below.

In the invention 1, as the first component, the compound represented by the general formula (I)
Contains one or more compounds selected from the group consisting of one to ten, preferably one to eight, more preferably one to eight.
Species to 5 are particularly preferred. R ¹ is preferably an alkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, and an unsubstituted linear alkyl group having 1 to 8 carbon atoms or an alkenyl group having 2 to 8 carbon atoms. More preferably, an unsubstituted linear alkyl group having 1 to 5 carbon atoms or an alkenyl group having 2 to 5 carbon atoms is particularly preferable.
The structure of (e) is more preferable.

[0056]

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(The structural formula is assumed to be linked to the ring at the right end.) Ring A is preferably a trans-1,4-cyclohexylene group or a 1,4-phenylene group, and is preferably a trans-1,4-cycloalkyl group. A hexylene group is more preferred, and ring B is preferably a trans-1,4-cyclohexylene group, a 1,4-phenylene group or a single bond, more preferably a 1,4-phenylene group or a single bond, and particularly preferably a single bond. preferable. L ¹ and L ² are each independently -COO-, -OCO-, -CH ₂ O-, -OCH _2- , -CH ₂ CH _2- , -CH = CH
-, - C≡C -, - ( CH 2) 4 -, - CH = CH-CH 2 CH 2 -, - CH 2 CH 2 -CH = CH
-Or a single bond, but -COO-, -OCO-, -CH ₂ CH _2- ,
-C≡C-,-(CH ₂ ) ₄ -or a single bond is preferable, and -CH ₂ CH
_2- , -C≡C- or a single bond is more preferable, -CH ₂ CH ₂ -or a single bond is particularly preferable, and a single bond is further preferable. m is 0 to 2, preferably 0 or 1, and more preferably 0. X ¹ and X ² are H or F, but X ¹ is F and X ² is H
It is preferable to represent Y ¹ is -F, -CF ₃ , -OCF ₃ , -OCHF
₂ , —OCH ₂ F, —CN, and R ¹ have the same definition or formula (I-1), but formula (I-1) is preferable. In formula (I-1), X ³ and X ⁴ each independently represent H, F or Cl, but H or F
Preferably, at least one of X ³ or X ⁴ is and particularly preferably a F. Q ¹ is -OCH _2- , -OCF _2- , -OCHF-, -CF _2-
Alternatively, it represents a single bond, preferably -OCF _2- , -OCHF-, -CF ₂ -or a single bond, more preferably -OCF ₂ -or a single bond, and more preferably a single bond. Y ² represents F, Cl or CN, with F being preferred. The second component contains one or more compounds selected from the general formula (II), but one to two
0 types are preferred, 1 to 15 types are more preferred, and 1 to 10 types are particularly preferred. R ² is an unsubstituted linear carbon number 1
~ 15 alkyl groups or alkenyl groups having 2 to 15 carbon atoms are preferable, and unsubstituted linear alkyl groups having 1 to 10 carbon atoms or alkenyl groups having 2 to 10 carbon atoms are more preferable.
Unsubstituted linear alkyl group having 1 to 8 carbon atoms or carbon number
Particularly preferred are 2 to 6 alkenyl groups. Among the alkenyl groups, the structures of the following formulas (a) to (e) are more preferred.

[0058]

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(The structural formula is assumed to be connected to the ring at the right end.) L ³ and L ⁴ are —COO—, —OCO—, —CH ₂ CH ₂ —, —C≡C—, and
(CH ₂ ) ₄ -or a single bond is preferred, -CH ₂ CH _2- , -C≡C-
Alternatively, a single bond is more preferable, and —CH ₂ CH ₂ — or a single bond is particularly preferable. It is preferable that at least one of X ⁵ and X ⁶ is F. n is preferably 0 or 1. Q
² represents a single bond, -CF _2- , -OCF ₂ -or -OCHF-,
-CF ₂ -, - OCF ₂ - or a single bond are preferred, -OCF ₂ - or a single bond is more preferably a single bond is particularly preferred. Y ³
Represents -F, -Cl or -CN, preferably -F or -CN.

The invention 2 contains at least two or more compounds of the general formula (I), preferably 2 to 10 and more preferably 2 to 5
Species are more preferred. In Invention 3, the content of the compound of the general formula (I) is in the range of 5 to 40% by mass, preferably 5 to 35% by mass, and more preferably 5 to 30% by mass. Invention 4 includes at least two or more compounds of the general formula (II),
Species are preferred, 2 to 15 are more preferred, and 2 to 10 are particularly preferred.

In the invention 5, R ² is preferably an alkyl group having 1 to 15 carbon atoms or an alkenyl group having 2 to 15 carbon atoms, more preferably an alkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms. The alkyl group having 1 to 8 carbon atoms or the alkenyl group having 2 to 6 carbon atoms is particularly preferable, and the structures of the following formulas (a) to (e) are more preferable for the alkenyl group.

[0062]

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(Structural formulas are those connected to the ring at the right end.
I do. ) L^Five, L⁶Is -COO-, -OCO-, -CH_TwoCH _Two-, -C≡C-,-(C
H_Two)_Four-Or a single bond is preferable, and -CH_TwoCH_Two-, -C≡C-
Or a single bond is more preferable, and -CH_TwoCH_Two-Or single bond
Is particularly preferred. Y^FourIs F, -CF_Three, -OCF_ThreeOr -OCHF_TwoTo
Represents F or -OCF_ThreeIs preferred, F is more preferred
No.

In the invention 6, R ² is preferably an alkyl group having 1 to 15 carbon atoms or an alkenyl group having 2 to 15 carbon atoms, more preferably an alkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, An alkyl group having 1 to 8 carbon atoms or an alkenyl group having 2 to 6 carbon atoms is particularly preferable, and structures of the following formulas (a) to (e) are more preferable for the alkenyl group.

[0065]

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(The structural formulas are those which are connected to the ring at the right end.
I do. ) L^Five, L⁶Is -COO-, -OCO-, -CH_TwoCH _Two-, -C≡C-,-(C
H_Two)_Four-Or a single bond is preferable, -COO-, -CH_TwoCH_Two-, -C
≡C- or a single bond is more preferable, -COO-, -CH_TwoCH_Two-
Alternatively, a single bond is particularly preferred. Y^FourIs F, -CF_Three, -OCF_Three,
-CN or -OCHF_TwoWherein CN is preferred. X^Five, X⁶Is
Each independently represents H or F, but at least one of
Is preferably F.

Invention 7 contains at least two or more compounds of the general formula (II-a), preferably 2 to 20 and more preferably 2 to 1
Five are more preferred, and two to ten are particularly preferred. Invention 8
Contains at least two or more compounds of the general formula (II-b), preferably 2 to 20, more preferably 2 to 15, and particularly preferably 2 to 10. In the invention 9, the general formula
The content of the compound (I) is in the range of 5 to 40% by mass,
Mass% is preferable, and 5 to 30 mass% is more preferable.
The content of general formula (II), general formula (II-a) and general formula (II-b) is 5
To 95% by mass, preferably 10 to 70% by mass,
~ 60 mass% is more preferable.

In the invention 10, R ³ and R ⁴ are each independently an optionally substituted fluorine-substituted alkyl group or alkoxyl group having 1 to 16 carbon atoms, an alkenyl group having 2 to 16 carbon atoms, and 3 carbon atoms. Represents an alkyl group having 1 to 12 carbon atoms, which is substituted with an alkenyloxy group having 16 to 16 carbon atoms or an alkoxyl group having 1 to 10 carbon atoms,
A 16 alkyl group or an alkenyl group having 2 to 16 carbon atoms is preferable, an alkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms is more preferable, and an alkyl group having 1 to 8 carbon atoms or 2 carbon atoms is preferable. Particularly preferred are alkenyl groups of the formulas (a) to (e).

[0069]

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(The structural formula is assumed to be linked to the ring at the right end.) Ring F, ring G and ring H are each independently a 1,4-phenylene group or a trans-1,4-cyclohexylene group. preferable. o represents 0, 1 or 2, preferably 0 or 1. L ⁷ and L ⁸ are each independently a single bond, -CH ₂ CH ₂ -,-(C
H ₂ ) ₄ —, —OCH ₂ —, —CH ₂ O— or —C≡C—, preferably a single bond or —CH ₂ CH ₂ —, more preferably a single bond.
Further, the compound of the general formula (III) contains at least one or more, preferably 1 to 20, more preferably 2 to 15,
Two to ten are particularly preferred.

In the invention 12, among the general formulas (Ia) to (Ie), the general formulas (Ia), (Ib), (Ic) and (Ie) are preferable, and the general formulas (Ia) and (Ic) are more preferable. , The following general formula (Ia-
1) to (Ia-8) and (Ic-1) to (Ic-8) are particularly preferred.

[0072]

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(Wherein ^Ra represents an alkyl group having 1 to 5 carbon atoms or a structure of the following formulas (a) to (e)):

[0074]

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(The structural formula is connected to the ring at the right end.) In the invention 13, the content of the compound of the general formula (III) or the general formula (III-a) is in the range of 5 to 95% by mass. Yes, but 10-70 mass
% Is preferable, and 10 to 50% by mass is more preferable.

In Inventions 14 and 15, R ⁵ has 1 carbon atom
Represents an alkyl group having 16 to 16 carbon atoms or an alkenyl group having 2 to 8 carbon atoms, but has an alkyl group having 1 to 10 carbon atoms or 2 carbon atoms.
~ 10 alkenyl groups are preferred, alkyl groups having 1 to 8 carbon atoms or alkenyl groups having 2 to 8 carbon atoms are more preferred,
An alkyl group having 1 to 6 carbon atoms or an alkenyl group having 2 to 6 carbon atoms is particularly preferable, and the alkenyl group has the following formulas (a) to (e)
Is more preferable.

[0077]

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(The structural formula is connected to the ring at the right end.) The content of the compound of the general formula (II-c) or (II-d) is in the range of 5 to 40% by mass. But 10 to 40 mass
% Is preferable, and 10 to 30% by mass is more preferable. It also contains at least one or more compounds of the general formula (II-c) or general formula (II-d), preferably 1 to 10 types, more preferably 1 to 8 types, and 1 to 5 types. Is particularly preferred.

In the invention 16, R ⁶ , R ⁷ , R ⁸ and R ⁹ represent an alkyl group having 1 to 8 carbon atoms or an alkenyl group having 2 to 8 carbon atoms, and an alkyl group having 1 to 6 carbon atoms. Alternatively, an alkenyl group having 2 to 6 carbon atoms is preferable, and structures of the following formulas (a) to (e) are more preferable for the alkenyl group.

[0080]

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(The structural formula is linked to the ring at the right end.) The content of the compound of the general formula (III-b) or (III-c) is in the range of 5 to 40% by mass. However, 10 to 40% by mass is preferable, and 10 to 30% by mass is more preferable. Further, at least one or more of the general formula (III-b) or the general formula (III-
Although the compound of c) is included, 1 to 10 are preferable, 1 to 8 are more preferable, and 1 to 5 are particularly preferable.

In the invention 18, R ¹ represents an alkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, and is preferably an alkyl group having 1 to 8 carbon atoms or an alkenyl group having 2 to 8 carbon atoms. The alkyl group having 1 to 5 carbon atoms or the alkenyl group having 2 to 5 carbon atoms is particularly preferable, and the structures of the following formulas (a) to (e) are more preferable for the alkenyl group.

[0083]

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(The structural formula is assumed to be connected to the ring at the right end.) L ¹ represents —CH ₂ CH ₂ — or a single bond, preferably a single bond. X ³ and X ⁴ are each independently H or F
Wherein at least one of them preferably represents F. Y
⁵ represents -F, -CF ₃ , -OCF ₃ , -OCHF ₂ , -OCH ₂ F, -CN, -F, -OCF ₃ , -OCHF ₂ , -CN is preferred, F is more preferred, The aforementioned general formulas (Ia-1) to (Ia-8) and (Ic-1) to (Ic-
8) is particularly preferred.

The above nematic liquid crystal composition can be used for AM-LCD and STN-
Although useful for LCDs, it is particularly useful for AM-LCDs and can be used for transmissive or reflective liquid crystal display devices. The liquid crystal medium of the present invention may contain a normal nematic liquid crystal, a smectic liquid crystal, a cholesteric liquid crystal, etc., in addition to the above compounds.

[0086]

EXAMPLES The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. Further, “%” in the compositions of the following Examples and Comparative Examples means “% by mass”. The characteristics measured in the examples are as follows. TN-I: Nematic phase-isotropic liquid phase transition temperature (° C.) T → N: Solid phase or smectic phase-nematic phase transition temperature (° C.) Vth: Threshold voltage when a TN-LCD with a cell thickness of 6 μm is formed (V) Δε: dielectric anisotropy Δn: birefringence τr = τd: response speed (msec)

(Example 1, Comparative Example 1) Nematic liquid crystal composition
No.1

[0088]

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Was prepared. Further, (I) of this composition (No. 1)
a-2a) and (Ic-2a) with (R-1) and (R-2)

[0090]

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Table 1 shows the results of measuring various properties together with the composition (Comparative Example 1) replaced with the composition.

[0092]

[Table 1]

As shown in Table 1, although the liquid crystal composition of Example 1 had a threshold voltage close to that of the composition of Comparative Example 1, the liquid crystal phase upper limit temperature was as high as 13 ° C. and the response speed was higher. And 8msec faster. When the voltage holding ratio was measured using the composition prepared here, it showed a high value of 99% at 80 ° C., and a liquid crystal display device having excellent display characteristics was able to be manufactured.

Example 2 Synthesis of Formula (Ia-2a)

[0095]

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A solution of 30 g of trans-6-propyl-5,6,7,8-tetrahydronaphthalen-2-ol and 2.3 g of sodium trifluoromethanesulfonate in 120 ml of methylene chloride at room temperature was treated with N, N'-bistetrafluoroborate. Difluoro-2,2 '
-27 g of dipyridinium (MEC31, manufactured by Daikin Industries, Ltd.) was added. After stirring at room temperature for 8 hours, the reaction was quenched by adding the reaction system to water, and a 10% aqueous hydrochloric acid solution was added, followed by extraction with toluene.
After washing the organic layer with water, the crude product which is a mixture of 1-fluoro and 3-fluoro forms obtained by evaporating the solvent is subjected to silica gel chromatography (silica gel 50 times, hexane: ethyl acetate = 9: 1). Purification gave 1-fluoro-trans-6-propyl-5,6,7,8-tetrahydronaphthalen-2-ol (5.4 g). MS: m / e = 268 (M ⁺ )

1-fluoro-trans-6-propyl-5,6,7,8
To a solution of 5 g of -tetrahydronaphthalen-2-ol and 7.9 g of trifluoromethanesulfonic anhydride in 40 ml of methylene chloride, 3 ml of pyridine was added dropwise. After stirring for 1 hour, a 10% aqueous hydrochloric acid solution was added, and the mixture was extracted with toluene. After washing the organic layer with water, the crude product obtained by evaporating the solvent was purified by silica gel chromatography (silica gel 10-fold, hexane) to give 1-fluoro-trans-6-propyl-5-trifluoromethanesulfonic acid. 6.1 g of 6,7,8-tetrahydronaphthalen-2-yl were obtained.

Under a nitrogen atmosphere, 5 g of 1-fluoro-trans-6-propyl-5,6,7,8-tetrahydronaphthalen-2-yl trifluoromethanesulfonate and 0.5 g of dibromobis (triphenylphosphine) nickel (II) A Grignard reagent prepared from 4.2 g of 3,4,5-trifluorobromobenzene and 0.49 g of magnesium was added dropwise to a 20 ml solution of THF. After stirring for 1 hour, a 10% aqueous hydrochloric acid solution was added, and the mixture was extracted with toluene. After washing the organic layer with water, the crude product obtained by evaporating the solvent is subjected to silica gel chromatography (silica gel 1).
0-fold, hexane) to purify 1-fluoro-6- (trans-4
-Propylcyclohexyl) -2- (3,4,5-trifluorophenyl) -5,6,7,8-tetrahydronaphthalene (0.9 g) was obtained. MS: m / e = 322 (M ⁺ )

(Example 3) General-purpose p-type host liquid crystal composition (H)

[0100]

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This (H) shows a nematic phase at 116.7 ° C. or less, and its melting point is 11.0 ° C. (H) TN with a cell thickness of 6.0 μm
The liquid crystal element was prepared by filling the cell, and the electro-optical characteristics at 20 ° C. were as follows. Threshold voltage (Vth) 2.14 V Dielectric constant anisotropy (Δε) 4.8 Refractive index anisotropy (Δn) 0.090 Next, 80% by mass of this (H) and the compound (Ia) of the present invention obtained in Example 2 (Ia -2a) to prepare a liquid crystal composition (H-1) consisting of 20% by mass, filling a TN cell having a cell thickness of 6.0 μm to form a liquid crystal element, and measuring its electro-optical properties at 20 ° C. It was as follows. Threshold voltage (Vth) 1.51V Dielectric anisotropy (Δε) 6.3 Refractive index anisotropy (Δn) 0.092

[0102]

According to the liquid crystal material of the present invention and the combination of the liquid crystal materials, a liquid crystal medium having a low threshold voltage, a wide nematic temperature range, a low viscosity and an excellent high-speed response can be obtained. When this composition was used for a liquid crystal display device, the contrast and reliability were high and excellent. This liquid crystal display is very practical as STN and AM-LCD.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Haruyoshi Takatsu 3-6-27 Nakahara, Higashiyamato-shi, Tokyo F-term (reference) 4H027 BA01 BB03 BB04 BC04 BD02 BD03 BD04 BD05 BD08 BE04 BE05 CQ02 CQ04 CR04 CT04 CU04 CW02 DK04 DK05

Claims (22)

[Claims] 1. A liquid crystal medium based on a mixture of polar compounds having a positive dielectric anisotropy, comprising a compound of the general formula (I) (In the formula, R ¹ is an alkyl group having 1 to 15 carbon atoms or 2 carbon atoms.
Which is unsubstituted this group there in 15 alkenyl group, or has at least one halogen as a substituent, and the one or more CH ₂ groups present in the group -O-, -S-, -CO-, -COO-, -OCO-, -OCO-
It may be replaced by O-. Y ¹ is -F, -Cl, -C
F ₃ , -OCF ₃ , -OCHF ₂ , -OCH ₂ F, -CN, the same definition as that of R ¹ or a formula (I-1) (Wherein X ³ and X ⁴ are each independently H, F or Cl, Q ¹ is -OCH _2- , -OCF _2- , -OCHF-, -CF ₂ -or a single bond, and Y ² Is F, Cl or CN). Ring A and Ring B
Are each independently a (a) trans-1,4-cyclohexylene group (in which one CH ₂ group or two or more non-adjacent CH ₂ groups are -O- and / or may be replaced -S- in) (b) 1,4-phenylene group (one more CH ₂ groups not CH ₂ group or adjacent that present in the group replaced by -N- (C) 1,4-cyclohexenylene, 1,4-bicyclo (2.2.2) octylene, piperidine-1,4-diyl, naphthalene-2,6-diyl, decahydronaphthalene-2, 6-diyl and 1,2,3,4-
Tetrahydronaphthalene-2,6-diyl (d) a group selected from the group consisting of a single bond,
(a), group (b) and group (c) may be substituted with CN or halogen, but when ring B represents a single bond, Y ¹ represents formula (I-1). L ¹ and L ² are each independently -COO-, -OCO-, -C
H ₂ O-, -OCH _2- , -CH ₂ CH _2- , -CH = CH-, -C≡C-,-(CH ₂ )
_{4 -, - CH = CH-} CH 2 CH 2 -, - a CH ₂ CH ₂ -CH = CH- or a single bond, but X ^1, X ² is H or F, X ¹ and X ² are different ,
m is 0 to 2. One or two compounds selected from
Containing at least one species and further having the general formula (II): (Wherein R ² is independently the same as defined for R ¹ in formula (I), and ring C and ring D are each independently of each other, (d) trans-1,4-cyclohexylene group (the one or more CH ₂ groups not CH ₂ group or adjacent the present in group may be replaced by -O- and or -S-) (e) 1,4-phenylene group (the one or more CH ₂ groups not CH ₂ group or adjacent the present in the radical may be replaced by a-N-) (f) 1,4-cyclohexenylene, 1, 4-bicyclo (2.2.2) octylene, piperidine-1,4-diyl, naphthalene-2,6-diyl, 1,2,3,4-tetrahydronaphthalene-2,6-diyl and decahydronaphthalene-2,6 -A group selected from the group consisting of diyl, the above group (d), group (e), group (f) may be substituted with CN or halogen, 1,2,3,4-tetrahydro When representing naphthalene-2,6-diyl, it is unsubstituted or L ³ and L ⁴ are each independently of each other, L ³ and L ⁴ in the formula (1)
¹ and L ² have the same definition, X ⁵ and X ⁶ are each independently H or F, n is 0, 1 or 2, and Y ³ is-
F, -Cl or -CN, and Q ² is a single bond, -CF _2- , -OCF
₂ -or -OCHF-. A liquid crystal medium comprising one or more compounds of the above). 2. The liquid crystal medium according to claim 1, comprising at least two or more compounds of the general formula (I). 3. The compound of the general formula (I) has a content of 5 to 40% by mass.
3. The liquid crystal medium according to claim 1, wherein the liquid crystal medium has a range of%. 4. The liquid crystal medium according to claim 1, comprising at least two compounds of the general formula (II). 5. The compound of the general formula (II)
a) (Wherein R ² has the same meaning as in formula (II),
L ⁵ and L ⁶ are each independently -CH ₂ CH _2- , -CH = CH-, -C≡C
-,-(CH ₂ ) ₄ -or a single bond, ring D represents a 1,4-phenylene group or trans-1,4-cyclohexylene group, X ⁶ represents H or F, n is 0 or Represents 1, Y ⁴
Represents F, -Cl, -CF ₃ , -OCF ₃ or -OCHF ₂ . 5. The liquid crystal medium according to claim 1, further comprising a compound of the formula (1). 6. A compound represented by the general formula (II):
b) (Wherein R ² has the same meaning as in formula (II),
L ⁵ and L ⁶ are each independently -COO-, -OCO-, -CH ₂ O-, -O
CH _2- , -CH ₂ CH _2- , -CH = CH-, -C≡C-,-(CH ₂ ) ₄ -or a single bond, and Ring C and Ring D are each independently 1,4- X represents a phenylene group or a trans-1,4-cyclohexylene group, X ⁵ and X ⁶ each independently represent H or F, and Y ⁴ represents
_{F, -Cl, -CF 3, -OCF} 3, -CN, or -OCHF ₂ represents. 6. The liquid crystal medium according to claim 1, further comprising a compound of the formula (1). 7. The compound of the general formula (II-a)
7. The liquid crystal medium according to claim 1, comprising at least one kind. 8. The compound of the general formula (II-b)
8. The liquid crystal medium according to claim 1, comprising at least one kind. 9. The content of the general formula (I) is in the range of 5 to 40% by mass, and the general formula (II), the general formula (II-a) and the general formula (II-b)
9. The liquid crystal composition according to claim 1, wherein the content of is from 5 to 95% by mass. 10. In addition to the general formulas (I) and (II), a general formula
(III) (In the formula, R ³ and R ⁴ may be independently fluorine-substituted alkyl or alkoxyl groups having 1 to 16 carbon atoms, alkenyl group having 2 to 16 carbon atoms, 3 to 16 carbon atoms An alkenyloxy group, or
Represents an alkyl group having 1 to 12 carbon atoms substituted with 10 alkoxyl groups, and ring F, ring G and ring H are each independently a 1,4-phenylene group optionally substituted by a fluorine atom, 2 -Methyl-1,4-phenylene group, 3-methyl-1,4-phenylene group, naphthalene-2,6-diyl group, phenanthrene-2,
7-diyl group, fluorene-2,7-diyl group, trans-1,4-
Cyclohexylene group, 1,2,3,4-tetrahydronaphthalene
-2,6-diyl group, decahydronaphthalene-2,6-diyl group,
Trans-1,3-dioxane-2,5-diyl group, pyridine-2,5
-Diyl group, pyrimidine-2,5-diyl group, pyrazine-2,5-
Represents a diyl group or a pyridazine-2,5-diyl group, and o is
0, 1 or 2, L ⁷ and L ⁸ are each independently a single _{bond, -CH 2 CH 2 -, -} (CH 2) 4 -, - OCH 2 -, - CH 2 O- or -C≡ C
-Represents 10. The liquid crystal medium according to claim 1, comprising at least one compound selected from the group consisting of: 11. A compound represented by the general formula (III):
(III-a) (Wherein R ³ and R ⁴ represent the same meaning as in formula (III), and ring H is
Represents a 1,4-phenylene group or a trans-1,4-cyclohexylene group, and o represents 0 or 1. 11. The liquid crystal medium according to claim 10, comprising a compound of the formula (11). 12. A compound of the general formula (I):
12. The liquid crystal medium according to claim 1, comprising at least one compound selected from (Ia) to (Ie). Embedded image (In the formula, R ¹ , X ¹ , X ² , X ³ , X ⁴ , Q ¹ and Y ² represent the same meaning as in the general formula (I).) 13. The liquid crystal medium according to claim 10, wherein the content of the compound of the general formula (III) or the general formula (III-a) is in the range of 5 to 95% by mass. 14. A compound represented by the general formula (II-c) represented by the general formula (II) or (II-a): (In the formula, R ⁵ represents an alkyl group having 1 to 16 carbon atoms or an alkenyl group having 2 to 8 carbon atoms.) The compound contains one or more compounds selected from the group consisting of 14. The liquid crystal medium according to claim 1, wherein the content is in a range of from about 40% by mass to about 40% by mass. 15. A compound represented by the general formula (II-d) represented by the general formula (II) or (II-a): (In the formula, R ⁵ represents an alkyl group having 1 to 16 carbon atoms or an alkenyl group having 2 to 8 carbon atoms.) The compound contains one or more compounds selected from the group having a content of 5 to 40 mass
15. The liquid crystal medium according to claim 1, wherein the ratio is in the range of%. 16. A compound of the general formula (III) or the general formula (III-a) represented by the general formula (III-b): (Wherein, R ⁶ and R ⁷ each independently represent an alkyl group having 1 to 8 carbon atoms or an alkenyl group having 2 to 8 carbon atoms.) And when its content is in the range of 5 to 40% by mass, the general formula (I
II-c) Wherein R ⁸ and R ⁹ each independently represent an alkyl group having 1 to 8 carbon atoms or an alkenyl group having 2 to 8 carbon atoms. 16. The liquid crystal medium according to claim 10, wherein the content is in the range of 5 to 60% by mass. 17. A compound of the general formula (I) or the general formula (Ia) containing one or more compounds, and the content thereof is 5 to 40.
In the range of mass%, and still contains one or two or more compounds of the general formula (II), general formula (II-a) or general formula (II-b), the content is 5 to 40 mass% In addition, the compound of the general formula (III), the general formula (III-a), the general formula (III-b) or the general formula (III-c) contains one or more compounds, and its content 17. The liquid crystal medium according to claim 1, wherein is in the range of 5 to 60% by mass. 18. A compound of the general formula (I-1) (In the formula, R ¹ is an alkyl group having 1 to 10 carbon atoms or 2 carbon atoms.
Represents an alkenyl group of ~ 10, ring A represents a 1,4-phenylene group or trans-1,4-cyclohexylene group, L ¹ is-
CH ₂ CH ₂ -or represents a single bond, X ¹ , X ² represents H or F, X ¹ and X ² are different, X ³ and X ⁴ each independently represent H or F, m Represents 0 or 1, and Y ⁵ represents-
_{F, -CF 3, -OCF 3,} -OCHF 2, represents -OCH ₂ F, the -CN. ). 19. The liquid crystal medium according to claim 1, comprising the formula (I-1). 20. A liquid crystal display device using the liquid crystal medium according to claim 1. Description: 21. A super twisted nematic (STN) liquid crystal display device using the liquid crystal composition according to claim 1 and having a twist angle of 220 ° to 270 °. 22. An active matrix (AM) liquid crystal display device using the liquid crystal medium according to claim 1. Description: