WO2013078766A1

WO2013078766A1 - Liquid crystal composition and liquid crystal display element containing the liquid crystal composition

Info

Publication number: WO2013078766A1
Application number: PCT/CN2012/001569
Authority: WO
Inventors: 李鹏飞; 宋晓龙; 王盼盼; 季飞; 吴凤; 游石枝
Original assignee: 江苏和成显示科技股份有限公司
Priority date: 2011-11-28
Filing date: 2012-11-22
Publication date: 2013-06-06
Also published as: CN102492430A

Abstract

A liquid crystal composition having low viscosity, properly high optical anisotropy and dielectric anisotropy (△ε) and a liquid crystal display element containing the composition are provided. The liquid crystal composition comprises, based on weight, (1) 2-25 % of the compound of formula I, (2) 3-40 % of the compound of formula II, (3) 5-60 % of the compound of formula III, (4) 0-45 % of the compound of formula IV, (5) 0-20 % of the compound of formula V, and (6) 0-30 % of the compound of formula VI. The liquid crystal composition can be used in display devices having a thinner cell gap, has good low temperature intersolubility, and can be stored in a container for a long time without crystallization in a low temperature environment.

Description

TECHNICAL FIELD The present invention relates to a liquid crystal composition and a liquid crystal display device comprising the liquid crystal composition, particularly a negative dielectric anisotropic liquid crystal composition and a liquid crystal display device. More specifically, the present invention relates to a liquid crystal composition having a low viscosity, suitably high optical anisotropy (??) and dielectric anisotropy (??), and a liquid crystal display element containing the same. Background Art As a most important flat panel display device, liquid crystal display devices (LCDs) have been developed rapidly in recent years, and their use has become increasingly widespread. LCD has the advantages of light weight, thin profile and low power consumption. The liquid crystal display mode can be divided into many types: phase change (hereinafter referred to as PC), twisted nematic (TN), super nematic (STN), and electronically controlled birefringence. (electrically controlled birefringence, hereinafter referred to as ECB), optically compensated bend (hereinafter referred to as OCB), IPS, VA, and the like. As the technology's latch-up is updated, the response requirements of liquid display devices are becoming stricter. However, in VA mode, insufficient response has always been an intractable problem. Especially in the field display, the response requirements are more stringent. The calculation formula for the opening and closing times is as follows:

opening time

_{ο οη} = η/(εΔεν ² -Κπ ² /(1 ² )

Closing time

Wherein C n C ₂ is a constant, η is a viscosity coefficient, Δ ε is a dielectric constant difference, Κ is an elastic coefficient, and d is a liquid crystal layer thickness. It can be derived from the above formula, T. _n and T. _Ff increases greatly as η increases, so lowering the viscosity coefficient can increase the response speed. Also, reducing the thickness of the liquid crystal layer can greatly reduce the turn-on time of the response time. As can be seen from the above relationship, the response time can be shortened by lowering the viscosity coefficient of the liquid crystal composition or increasing the modulus of elasticity. However, if the viscosity is lowered to improve the response time, the elastic modulus of the liquid crystal and the isotropic phase transition temperature will also decrease. Also, if the modulus of elasticity increases, the threshold voltage and viscosity will tend to increase. Therefore, in order to improve response time, the balance between these two properties must be minimized. In the VA mode, in order to obtain a large contrast of the display, the product of the optical anisotropy (Δη) of the composition and the cell gap (d) of the device (Δη.φ) is designed to be a fixed value. The range of 0.30μηι to 0.40μηη. Since the cell gap (d) is usually in the range of 2μπι to 6μηη, the optical anisotropy of the composition is mainly in the range of 0.05 to 0.20. We know that the stronger the polarity, the lower the threshold, the work The smaller the consumption, the higher the viscosity, so in order to achieve a faster response, we need to balance the relationship between the various parameters, reduce the viscosity of the system and achieve fast response based on the selection of appropriate refractive index and dielectric. . In the VA mode, the increase in the number of driving paths is also the direction of development in the world today. At present, the more common method is to improve the steepness by increasing the value of Δη. (1), the increase of An.d will inevitably lead to an increase in viscosity, so There is an urgent need for a low viscosity liquid crystal mixture to meet market demand. Currently, no single substance can satisfy the aforementioned properties as a single compound. For the preparation of liquid crystal compositions, all of these properties should be satisfied, which occurs due to small Δη or large In the negative liquid crystal composition disclosed in Chinese Patent Publication No. CN101072847A, the viscosity can be 17.6 (mPa - s), but the refractive index is 0.076, and the clearing point is 76 ° C. In the negative electrode liquid crystal composition disclosed in Chinese Patent No. CN101407719A, the refractive index is 0.186, and the viscosity thereof is 49.1 (mPa - s), but the threshold is not sufficiently low. The object of the present invention is Provided is a liquid crystal composition, in particular a VA type display, and in particular a liquid crystal group for the liquid crystal display The liquid crystal composition provided should have no disadvantages mentioned above, or only a slight degree of the above disadvantages. Further, the liquid crystal composition of the present invention is required to have both high specific resistance, wide viewing angle, and high definition bright spot. Good low-temperature miscibility, especially in the case where the cell of the liquid crystal composition is required to be stored at -30 ° C for 30 days, is not capable of crystallization. SUMMARY OF THE INVENTION To achieve the above object, an aspect of the present invention provides a liquid crystal combination , including the following weight percentages of each component:

(1) 2-25% of compounds of formula I

(2) 3-40% of compounds of formula II

(3) 5-60% formula

(4) 0-45% of the compound of formula IV

(5)

as well as

(6) 0-30% pass

among them,

In the compound of the formula I, R1 is a fluorenyl group of 1 to 12 carbon atoms, R2 is a fluorenyl group or a decyloxy group of 1 to 12 carbon atoms, and ring A represents a trans-1,4-cyclohexanyl group. Or 1,4-phenylene, n represents an integer of 0 or 1;

In the compound of the formula II, R3 is a fluorenyl group of 1 to 12 carbon atoms, R4 is a fluorenyl group or a decyloxy group of 1 to 12 carbon atoms, and ring B represents trans-1,4-cyclohexanyl. Or 1, 4-phenylene, n represents an integer of 0 or 1;

In the compound of the formula III, R5 is a fluorenyl group of 1 to 12 carbon atoms; R6 is a fluorenyl group or a fluorenyloxy group of 1 to 12 carbon atoms; and ring C represents a trans-1,4-cyclohexyl fluorenyl group. Or 1,4-phenylene, m represents an integer of 0 or 1;

In the compound of the formula IV, R7 and R8 are each independently a fluorenyl or a decyloxy group of 1 to 12 carbon atoms, and one or two non-adjacent -CH ₂ - may be -CH=CH- Replace

In the above formula V, R9 and R10 are each independently a fluorenyl group of 1 to 12 carbon atoms, and ring D represents a trans 1,4-cyclohexyl fluorenyl group or a 1,4-phenylene group, o, p Expresses an integer of 0 or 1;

In the compound of the formula VI, R11 is an alkyl group of 1 to 12 carbon atoms, R12 is a fluorenyl group or a decyloxy group of 1 to 12 carbon atoms, and k represents an integer of 1 or 2. The compound of the formula I of the present invention is preferably one or more of the following structures:

Wherein R1 is preferably an alkyl group of 1 to 5 carbon atoms, and R2 is preferably an alkyl group or a decyloxy group of 1 to 5 carbon atoms. The compound of the formula I of the present invention is particularly preferably a compound of the following structure. One or more:

Most preferably one or more of IA-5, IA-6, IA-7, IA-8, IB-5, IB-6, IB-7, IB-8, etc. ₍ Formula II of the present invention)

Wherein R3 is preferably an alkyl group of 1 to 5 carbon atoms, and R4 is preferably a mercapto group or alkoxy group of 1 to 5 carbon atoms. The compound of the formula II of the present invention is particularly preferably a compound of the following structure. One or more:

F F

CH -c≡c- -0C H 5 ΙΙ-Α-1

SlOO/ZlOiN3/X3d 99.8Z.0/CT0Z OAV

Most preferably one or more of the compounds II-A-2, II-A-4, II-A-6, Π-Β-2, II-B-4, II-B-6 and the like.

this invention

Wherein R5 is preferably a fluorenyl group of 1 to 5 carbon atoms; and R6 is preferably an alkyl group or a decyloxy group of 1 to 5 carbon atoms. One or more of the general formula III of the invention:

C. 2H' "5 OC H lll-C-1

Most preferably one or more of compounds such as III-A-1, III-A-2, III-BK III-B-2, III-CK III-C-2, etc. The compound represented by Chemical Formula IV has a small rotation. The viscosity and low melting point can effectively reduce the viscosity of the mixed liquid crystal and improve the low-temperature mutual solubility of the mixed liquid crystal. The compound of the formula IV of the present invention is preferably one or more of the following structures:

R7 and R8 are preferably an anthracenyl group or a decyloxy group of 1 to 5 carbon atoms.

The compound of the formula IV of the present invention is particularly preferably one or more of the following structures:

Most preferably one or more of the compounds IV-A-2, IV-A-4, IV-B-2, IV-B-4, IV-C-4, IV-C-6 _(the present invention The compound of the formula V is preferably one or more of the following structures:

Among them, R9 and R10 are preferably a fluorenyl group of 2 to 5 carbon atoms.

The compound of the formula V of the present invention is particularly preferably one or more of the following structures:

C. 3H' V -coo- -C _C H VA-3

Most preferably one or more of VAl, VA-2, VBK VB-2, VB-3, VB-4, etc., the general formula V of the present invention

Wherein R11 and R12 are preferably an anthracenyl group or a decyloxy group of 1 to 5 carbon atoms. The compound of the formula VI of the present invention is particularly preferably one or more of the following structures:

C 2H, ,5 -coo -O CH VI-A-1

VI-B-2

C, H ₇ - COO- CH

Most preferably one or more of VI-A-2, VI-A-4, VI-B-2, VI-B-4 and the like. The liquid crystal composition of the present invention is particularly preferably the following components by weight:

(1) 3-20% of a compound of formula I;

(2) 3 to 35% of a compound of the formula II;

(3) 10-55% of a compound of the formula III;

(4) 0-42% of a compound of the formula IV;

(5) 0-15% of a compound of the formula V;

(6) 0-27% of a compound of the formula VI. The invention can optimize the combination and optimize the liquid crystal composition obtained by matching a large number of known liquid crystal compounds, and the refractive index can be 0.150 (20 ° C) or more, so that it can be used on display devices with thinner thickness; viscosity Can be reduced to 22mm ² . s- ¹ (20 ° C) or less; Δ ε between -4.0 ~ - 11.0 (25 ° C); clear spots can reach above 90 ° C, have good low temperature miscibility, especially The liquid crystal is placed in a container and stored in a low temperature environment for a long time without crystallization. The liquid crystal composition of the invention has wide dielectric coverage and is suitable for products with different threshold segments; has a wide range of refractive index, can be used in a thinner liquid crystal display, thereby improving response speed; extremely low viscosity, Thereby having a fast response speed. Another aspect of the invention provides a liquid product display element comprising the liquid crystal composition of the invention. With the development of technology, people have higher requirements for the color and response of liquid crystal devices. In the increasingly fierce competition, the pressure and response requirements from cost are more prominent and important. In particular, in the field sequential display mode, the present invention can satisfy the fast response requirement from the viewpoint of improvement in liquid crystal performance in response to the demand for rapid response. In the context of the present invention, all temperatures are in degrees Celsius, and all percentages are by weight unless otherwise indicated. DETAILED DESCRIPTION OF THE INVENTION It is to be understood that the various embodiments are illustrative of the invention and are not intended to be limiting. For ease of expression, in the following examples, the group structure of the liquid compound is represented by the codes listed in Table 1. Table 1 Group structure code of liquid crystal compound

The structural formula is expressed by the code listed in Table 1, and can be expressed as: 3CW02, 3 in the code indicates the number of C atoms of the left-end alkyl group, that is, the alkyl group is -C ₃ H _7; C in the code represents the ring垸 base; W in the code represents the F-substituted structure of benzene plus two lateral positions, 0 in the code represents an oxygen atom; 2 in the code represents the number of C atoms in the right-end sulfhydryl group, which means that the fluorenyl group is -C ₂ H ₅ . The various liquid crystal components contained in the liquid crystal composition of the present invention are all compounds known in the art, wherein the compound of the formula I and the compound of the formula II are referred to in DE 2937700 A1/EP0675188 A, the formula III Compounds are referred to in CN1911888, compounds of the general formula V are referred to in EP 0087102 A1, and compounds of the general formula VI are referred to in DE 3807957 A1. The synthesis method of the compound of the general formula IV is relatively simple, and those skilled in the art can synthesize by a conventional method. The abbreviations of the parameters tested in the examples and the test conditions are as follows -

Cp clearing point (nematic phase -> transition temperature of each isotropic phase)

S->N low temperature phase transition point (smectic phase -> nematic phase transition temperature)

η bulk viscosity (mm ² /s, 20 ° C)

Δε dielectric anisotropy (25°C, 1KHZ)

Δη optical anisotropy (20°C, 589nm)

Vth threshold voltage (V, 25 ° C)

The flow viscosity Vise is tested using a cone and plate viscometer; The refractive index and refractive index anisotropy were measured using an Abbe refractometer under a sodium light (589 nm) light source at 20 °C. The test boxes used in the above tests are all 6μη negative boxes. Comparative example 1

Table 2 lists the weight percentages of the commercially available MERCK product components of the comparative liquid crystal composition. The comparative liquid crystal composition was filled in a test box for performance test, and the test results were also listed in the corresponding table.

EXAMPLE 1 The compounds and weight fractions listed in Tables 3 and 4 were formulated into the nematic liquid crystal compositions of the invention, which were filled in a test box for performance testing, and the test data are also listed in Tables 3 and 4, respectively. Example 1-1

Table 3 Example 1-1 Component weight percentage of liquid crystal composition and its performance test data

Example 1-2

Table 4 Examples 1-2 Component Weight Percent of Liquid Crystal Composition and Performance Test Data

As can be seen from the data of the above examples, the use of the liquid crystal composition of the present invention can reduce the viscosity by more than 30% on the basis of ensuring the refractive index, the dielectric anisotropy and the clearing point.

Comparative example 2

Table 5 lists the weight percentages of the commercially available MERCK product components of the comparative liquid compositions. The comparative liquid composition was filled in a test box for performance testing, and the test results are also listed in the corresponding table. Table 5 Weight percent of commercially available MERCK product components and performance test data

Example 2 The compounds and weight fractions listed in Tables 6 and 7 were formulated into the nematic liquid crystal compositions of the present invention, which were filled in a test box for performance testing, and the test data are also shown in Tables 6 and 7, respectively. Example 2-1

Table 6 Example 2-1 Component Weight Percent of Liquid Crystal Composition and Its Performance Test Data

Example 2-2

Table 7 Example 2-2 Component Weight Percent of Liquid Crystal Composition and Its Performance Test Data

From the data of the above examples and comparative examples, it can be seen that with the liquid crystal composition of the present invention, the viscosity is reduced by 20% or more on the basis of ensuring the refractive index, electrical anisotropy and clearing point.

Example 3

The compounds and weight fractions listed in Table 8 were formulated into the nematic liquid crystal compositions of the invention, which were filled in a test box for performance testing, and the test data are also listed in Table 8. Table 8 Example 3 Component weight percentage of liquid crystal composition and its performance test data

Example 4

The compounds and weight fractions listed in Table 9 were formulated into the nematic liquid crystal compositions of the invention, which were filled in a test box for performance testing, and the test data are also listed in Table 9. Table 9 Example 4 Component weight percentage of liquid crystal composition and its performance test data

Example 5

The compounds and weight fractions listed in Table 10 were formulated into the nematic liquid crystal compositions of the invention, which were filled in a test box for performance testing, and the test data are also listed in Table 10. Table 10 Example 5 Component Weight Percent of Liquid Crystal Composition and Its Performance Test Data

Example 6

The compounds and weight fractions listed in Table 11 were formulated into the nematic liquid crystal compositions of the invention, which were filled in a test box for performance testing, and the test data are also listed in Table 11. Table 11 Example 6 liquid

The composition of the present invention can also be used in a low threshold system, such as a refractive index of 0.15 and a dielectric of -11, and the viscosity can be within 137. The viscosity of similar products of other companies in the market is above 200. Example 7 The liquid crystal compositions prepared in Examples 1 to 6 were used for a liquid crystal display element in accordance with a conventional method. The above are only the preferred embodiments of the present invention, and are not intended to limit the invention, and other equivalent changes or modifications may be included in the claims without departing from the spirit of the invention. In the scope.

Claims

What is claimed is: 1. A liquid crystal composition comprising the following components by weight:

(1) 2-25% of Formula I

(2) 3-40

(3) 5-60% formula

(4) 0-45% of formula IV

(5) 0

as well as

(6) 0-30% formula

among them,

In the compound of the formula I, R1 is an alkyl group of 1 to 12 carbon atoms, R2 is an alkyl group or a decyloxy group of 1 to 12 carbon atoms, and ring A represents trans 1,4-cyclohexanyl. Or 1,4-phenylene, n represents an integer of 0 or 1;

In the compound of the formula II, R3 is a fluorenyl group of 1 to 12 carbon atoms, R4 is a fluorenyl group or a decyloxy group of 1 to 12 carbon atoms, and ring B represents a trans 1,4-cyclohexane. Or 1,4-phenylene, n represents an integer of 0 or 1;

In the compound of the formula III, R5 is a fluorenyl group of 1 to 12 carbon atoms; R6 is an alkyl group or a decyloxy group of 1 to 12 carbon atoms; and ring C represents a trans-1,4-cyclohexyl fluorenyl group. Or 1,4-phenylene, m represents an integer of 0 or 1;

In the compound of the formula IV, R7 and R8 are each independently an alkyl or a decyloxy group of 1 to 12 carbon atoms, wherein one or two of the non-adjacent -CH ₂ - may be -CH=CH - replaced;

In the above formula V, R9 and R10 are each independently a fluorenyl group of 1 to 12 carbon atoms, and ring D represents a trans 1,4- Cyclohexyl or 1,4-phenylene, o, p represents an integer of 0 or 1;

In the compound of the formula VI, R1 1 is an alkyl group of 1 to 12 carbon atoms, R12 is an alkyl group or a decyloxy group of 1 to 12 carbon atoms, and k represents an integer of 1 or 2.

The liquid crystal composition according to claim 1, wherein the compound of the formula I is selected from one or more of the following compounds:

Wherein R1 is an alkyl group of 1 to 5 carbon atoms, and R2 is an anthracenyl group or a decyloxy group of 1 to 5 carbon atoms.

The liquid crystal composition according to claim 1, wherein the compound of the formula II is one or more selected from the group consisting of

Wherein R3 is a fluorenyl group of 1 to 5 carbon atoms, and R4 is a fluorenyl group or alkoxy group of 1 to 5 carbon atoms.

The liquid crystal composition according to claim 1, wherein the compound of the formula is one or more selected from the group consisting of

Wherein R5 is a fluorenyl group of 1 to 5 carbon atoms, and R6 is a fluorenyl group or a decyloxy group of 1 to 5 carbon atoms.

The liquid crystal composition according to claim 1, wherein the compound of the formula IV is preferably one of the following structures or

Wherein, R7 and R8 are each independently alkyl with 1-5 carbon atoms or alkoxy of _t

The liquid crystal composition according to claim 1, wherein the compound of the formula V is selected from one of the following compounds

Wherein R9 and R10 are each independently an alkyl group of 2 to 5 carbon atoms.

The liquid crystal composition according to claim 1, wherein the compound of the formula VI is one or more selected from the group consisting of -

Wherein R11 and R12 are each independently an alkyl group or a decyloxy group of 1 to 5 carbon atoms.

The liquid crystal composition according to any one of claims 1 to 7, wherein

The compound of formula I is selected from one or more of the following compounds:

Three B2 --

Three 3A -- three A2 -- three A - The compound of formula IV is selected from one or more of the following structures:

. ₄ Η ₉ ·→^^> ~ ~ IV-B-3

One or more:

The compound of the VI is selected from one or more of the following structures:

9. The liquid crystal composition according to claim 8, wherein

The compound of the formula I is one or more of the compounds of the formulae I-A-5, I-A-6, I-A-7, I-A-8, I-B-5, I-B-6, I-B-7, I-B-8;

The compound of the formula II is one of the chemical formulas Π-Α-2, Π-Α-4, Π-Α-6, Π-Β-2, Π-Β-4, Π-Β-6 compounds or Multiple

The compound of the formula III is one or more of the chemical formulas ΙΠ-Α-1, ΙΠ-Α-2, III-B-K III-B-2, III-C-K ni-c-2 compounds ;

The compound of the formula IV is one of the compounds of the formula IV-A-2, IV-A-4, IV-B-2, IV-B-4, IV-C-4, IV-C-6 or Multiple

The compound of the formula V is one or more of the chemical formulas V-A-1, V-A-2, V-B-K V-B-2, V-B-3, V-B-4;

The compound of the formula VI is one or more of the compounds of the formulae VI-A-2, VI-A-4, VI-B-2, VI-B-4.

10. The liquid crystal composition according to claim 1, wherein the compound of the formula I accounts for 3-20% by weight of the total composition; the compound of the formula II accounts for the total weight of the composition. 3-35%; the compound of the formula III is 10-55% by weight of the total composition; the compound of the formula IV is 0-42% by weight of the total composition; The compound comprises from 0 to 15% by weight based on the total weight of the composition; and, the compound of the formula VI is from 0 to 27% by weight based on the total weight of the composition.

A liquid crystal display element comprising the liquid crystal composition according to any one of claims 1 to 10.