Negative dielectric anisotropic liquid crystal composition, liquid crystal display element and liquid crystal display

Abstract

The present invention relates to a negative dielectric anisotropic liquid crystal composition, a liquid crystal display element, and a liquid crystal display. The negative dielectric anisotropic liquid crystal composition of the present invention comprises a first component composed of one or more compounds represented by formula I and a second component composed of one or more polymerizable compounds: The negative dielectric anisotropic liquid crystal composition disclosed by the present invention has a low rotary viscosity, a fast response speed and a good stability, and is very suitable for manufacturing liquid crystal display elements, particularly suitable for PS (polymer-stabilized) or PSA (polymer-stabilized alignment)-type liquid crystal displays. ##STR00001##

Claims

1. A negative dielectric anisotropic liquid crystal composition, wherein said negative dielectric anisotropic liquid crystal composition comprises a first component composed of one or more compounds represented by formula I2 and a second component composed of one or more polymerizable compounds, ##STR00039## wherein R.sub.1 represents an alkyl group having a carbon atom number of 1-10; R.sub.2 represents —(CH.sub.2).sub.p—CH═CH—C.sub.qH.sub.2q+1, with p representing 1, 2 or 3, q representing 0, 1, 2 or 3.

2. The negative dielectric anisotropic liquid crystal composition according to claim 1, wherein said polymerizable compound is a compound represented by formula II: ##STR00040## wherein, R.sub.3 and R.sub.4 each independently represent W-Sp-, H, Cl, F, or an alkyl group having a carbon atom number of 1-12, with one or two non-neighboring CH.sub.2 groups in said alkyl group having a carbon atom number of 1-12 being optionally replaced by —O—, —CH.sub.2═CH.sub.2—, —CO—, —OCO— or —COO—, wherein at least one of R.sub.3 and R.sub.4 represents W-Sp-; ##STR00041## each independently represent a phenylene group, a phenylene group optionally substituted with W-Sp-, Cl, F, an alkyl group having a carbon atom number of 1-12 or an alkoxy group having a carbon atom number of 1-12, or an indanyl group, wherein one or two non-neighboring CH.sub.2 groups in said alkyl group having a carbon atom number of 1-12 and said alkoxy group having a carbon atom number of 1-12 are optionally replaced by —O—, —CH.sub.2═CH.sub.2—, —CO—, —OCO— or —COO—; furthermore, ##STR00042## and R.sub.3 are bonded at any position of ##STR00043## and ##STR00044## and R.sub.4 are bonded at any position of ##STR00045## n represents 0, 1 or 2; W represents a methacrylate group or an acrylate group; and V and Sp each independently represent a single bond, —COO—, —CH.sub.2O— or —CH.sub.2CH.sub.2—.

3. The negative dielectric anisotropic liquid crystal composition according to claim 2, wherein: the compound represented by formula II is selected from the group consisting of compounds represented by formulas II1-II4: ##STR00046## wherein R.sub.4 and K each independently represent W.sub.1-Sq-, H, Cl, F, or an alkyl group having a carbon atom number of 1-12, wherein one or two non-neighboring CH.sub.2 groups in said alkyl group having a carbon atom number of 1-12 is optionally replaced by —O—, —CH.sub.2═CH.sub.2—, —CO—, —OCO— or —COO—, W and W.sub.1 each independently represent a methacrylate group or an acrylate group; V, Sp, and Sq each independently represent a single bond, —COO—, —CH.sub.2O—, or —CH.sub.2CH.sub.2—; and each i independently represents 0, 1, 2, 3 or 4.

4. The negative dielectric anisotropic liquid crystal composition according to claim 1, wherein said negative dielectric anisotropic liquid crystal composition further comprises one or more compounds represented by formula III: ##STR00047## wherein R.sub.5 and R.sub.6 each independently represent an alkyl group having a carbon atom number of 1-10 or an alkoxy group having a carbon atom number of 1-10, and any one or more CH.sub.2 in R.sub.5 and R.sub.6 are optionally substituted with cyclopentyl, cyclobutyl or cyclopropyl; ##STR00048## each independently represent ##STR00049## and r represents 1 or 2.

5. The negative dielectric anisotropic liquid crystal composition according to claim 4, wherein said one or more compounds represented by formula III are selected from the group consisting of compounds represented by III1-III5, ##STR00050## wherein R.sub.5 and R.sub.6 are each independently an alkyl group having a carbon atom number of 1-10 or an alkoxy group having a carbon atom number of 1-10, and any one or more CH.sub.2 in R.sub.6 are optionally substituted with cyclopentyl, cyclobutyl or cyclopropyl.

6. The negative dielectric anisotropic liquid crystal composition according to claim 1, wherein said negative dielectric anisotropic liquid crystal composition further comprises one or more compounds represented by formula IV: ##STR00051## wherein R.sub.7 and R.sub.8 each independently represent an alkyl group having a carbon atom number of 1-10, a fluoro-substituted alkyl group having a carbon atom number of 1-10, an alkoxy group having a carbon atom number of 1-10, or a fluoro-substituted alkoxy group having a carbon atom number of 1-10, and any one or more CH.sub.2 in R.sub.7 and R.sub.8 are optionally substituted with cyclopentyl, cyclobutyl or cyclopropyl; Z.sub.1 and Z.sub.2 each independently represent a single bond, —COO—, —CH.sub.2O— or —CH.sub.2CH.sub.2—; ##STR00052## each independently represent ##STR00053## x represents 1, 2 or 3; and y represents 0 or 1.

7. The negative dielectric anisotropic liquid crystal composition according to claim 6, wherein said one or more compounds represented by formula IV are selected from the group consisting of compounds represented by formulas IV1 to IV13: ##STR00054## ##STR00055## wherein R.sub.7 and R.sub.8 each independently represent an alkyl group having a carbon atom number of 1-10, a fluoro-substituted alkyl group having a carbon atom number of 1-10, an alkoxy group having a carbon atom number of 1-10, or a fluoro-substituted alkoxy group having a carbon atom number of 1-10, and any one or more CH.sub.2 in R.sub.7 and R.sub.8 are optionally substituted with cyclopentyl, cyclobutyl or cyclopropyl.

8. The negative dielectric anisotropic liquid crystal composition according to claim 1, wherein said negative dielectric anisotropic liquid crystal composition further comprises one or more compounds represented by formula V: ##STR00056## wherein R.sub.9 and R.sub.10 each independently represents an alkyl group having a carbon atom number of 1-10, a fluoro-substituted alkyl group having a carbon atom number of 1-10, an alkoxy group having a carbon atom number of 1-10, a fluoro-substituted alkoxy group having a carbon atom number of 1-10, an alkenyl group having a carbon atom number of 2-10, a fluoro-substituted alkenyl group having a carbon atom number of 2-10, an alkenoxy group having a carbon atom number of 3-8 or a fluoro-substituted alkenoxy group having a carbon atom number of 3-8, and any CH.sub.2 in R.sub.9 and R.sub.10 are optionally substituted with cyclopentyl, cyclobutyl or cyclopropyl; and Q.sub.1 represents —O—, —S—, —CH.sub.2O— or —CH.sub.2S—.

9. The negative dielectric anisotropic liquid crystal composition according to claim 1, wherein in said negative dielectric anisotropic liquid crystal composition, the content of said compound represented by formula I2 is 1%-50% by mass.

10. A liquid crystal display element or liquid crystal display, comprising the negative dielectric anisotropic liquid crystal composition according to claim 1, said display element or display being a PSA-VA, PSA-OCB, PS-IPS, PS-FFS, PS-TN or SA-VA display element or display.

11. The negative dielectric anisotropic liquid crystal composition according to claim 2, wherein in said negative dielectric anisotropic liquid crystal composition, the content of said compound represented by formula II is 0.1%-1% by mass.

12. The negative dielectric anisotropic liquid crystal composition according to claim 4, wherein in said negative dielectric anisotropic liquid crystal composition, the content of said compound represented by formula III is 10%-50% by mass.

13. The negative dielectric anisotropic liquid crystal composition according to claim 6, wherein in said negative dielectric anisotropic liquid crystal composition, the content of said compound represented by formula IV is 1%-60% by mass.

14. The negative dielectric anisotropic liquid crystal composition according to claim 8, wherein in said negative dielectric anisotropic liquid crystal composition, the content of said compound represented by formula V is 1%-50% by mass.

Description

DETAILED DESCRIPTION OF EMBODIMENTS

(1) In order to illustrate the present invention more clearly, the present invention will be further described below in conjunction with preferred examples. A person skilled in the art should understand that the following detailed description is illustrative rather than limiting, and should not limit the scope of the invention.

(2) In the present invention, the preparation methods are all conventional methods unless otherwise specified, and the raw materials used are all available from open commercial approaches unless otherwise specified, the percentages all refer to mass percentages, the temperature is in degree Celsius (° C.), a liquid crystal compound is also referred to as a liquid crystal monomer, and the specific meanings of other symbols and the test conditions are as follows:

(3) Cp represents the clearing point (° C.) of a liquid crystal as measured by means of a DSC quantitative method;

(4) S—N represents the melting point (° C.) for the transformation of a liquid crystal from a crystal state to a nematic phase;

(5) Δn represents optical anisotropy, with Δn=n.sub.e−n.sub.o, wherein n.sub.o is the refractive index of an ordinary light, and n.sub.e is the refractive index of an extraordinary light, with the test conditions being: 25±2° C., 589 nm and using an abbe refractometer for testing;

(6) Δε represents dielectric anisotropy, with Δε=ε//−ε⊥, in which ε// is a dielectric constant parallel to a molecular axis, and ε⊥ is a dielectric constant perpendicular to the molecular axis, with the test conditions being 25±0.5° C., a 20 micron parallel cell, and INSTEC: ALCT-IR1 for testing;

(7) γ1 represents rotary viscosity (mPa.Math.s), with the test conditions being 25±0.5° C., a 20 micron parallel cell, and INSTEC: ALCT-IR1 for testing;

(8) ρ represents electrical resistivity (Ω.Math.cm), with the test conditions being: 25±2° C., and the test instruments being a TOYO SR6517 high resistance instrument and an LE-21 liquid electrode; and

(9) VHR represents voltage holding ratio (%), with the test conditions being: 20±2° C., a voltage of ±5 V, a pulse width of 10 ms, and a voltage holding time of 16.7 ms. The test equipment is a TOYO Model 6254 liquid crystal performance comprehensive tester;

(10) τ represents response time (ms), with the test instrument being DMS-501 and the test conditions being: 25±0.5° C., a test cell that is a 3.3 micron IPS test cell, an electrode spacing and an electrode width, both of which are 10 microns, and an included angle between the frictional direction and the electrode of 10°.

(11) Devices and instruments used for preparing liquid crystal media are:

(12) (1) an electronic precision balance (with an accuracy of 0.1 mg)

(13) (2) a stainless steel beaker for liquid crystal weighing

(14) (3) a spoon for adding a monomer

(15) (4) a magnetic rotor for stirring

(16) (5) a temperature-controlled electromagnetic stirrer.

(17) The method for preparing a liquid crystal medium comprises the following steps:

(18) (1) monomers to be used are placed in order and neatly;

(19) (2) a stainless steel beaker is placed on the balance, and the monomers are placed in the stainless steel beaker with a small spoon;

(20) (3) monomer liquid crystals are sequentially added thereto according to weights as required;

(21) (4) the stainless steel beaker to which the materials have been added is placed on the magnetic stirrer, heated and melted; and

(22) (5) after most of the mixture in the stainless steel beaker is melted, a magnetic rotor is added to the stainless steel beaker for uniformly stirring the liquid crystal mixture, and the mixture is cooled to room temperature to obtain the liquid crystal medium.

(23) In the examples of the present invention, liquid crystal monomer structures are represented by codes, and the codes for ring structures, end groups and linking groups of liquid crystals are represented as in Tables 1 and 2 below.

(24) TABLE-US-00001 TABLE 1 Corresponding code for ring structure Ring structure Corresponding code C P L G Gi Y 0 Sa Sb Sc Sd

(25) TABLE-US-00002 TABLE 2 Corresponding code of end group and linking group End group and linking group Corresponding code C.sub.nH.sub.2n+1— n- C.sub.nH.sub.2n+1O— nO— —OCF.sub.3 —OT —CF.sub.2O— -Q- —CH.sub.2O— —O— —F —F —CN —CN —CH.sub.2CH.sub.2— -E- —CH═CH— —V— —COO— -Z- —CH═CH—C.sub.nH.sub.2n+1 Vn— Cp- Cpr- Cpr1-

EXAMPLES

(26) ##STR00037##
the code of which is CC-Cp-V1; and

(27) ##STR00038##
the code is PGP-Cpr1-2.

Example 1

(28) The formulation and corresponding properties of the liquid crystal composition are as shown in table 3 below.

(29) TABLE-US-00003 TABLE 3 Formulation and corresponding properties of liquid crystal composition of Example 1 Category Liquid crystal monomer code Content (%) I CPP-3-2V1 1 II II5 0.1 II II6 0.2 II II9 0.1 III CC-3-V 18 III CC-2-3 8 III PP-5-1 14 III CCP-2-O1 4 III CPP-3-1 6 IV CCY-3-O4 11 IV CLY-3-O2 12 IV PYP-2-3 4 V Sa-4O-O5 5 V Sb-2O-O4 7 V Sc-2O-O4 6 V Sd-4O-O4 6 Performance S-N: ≤−40° C. parameters Δε [1 KHz, 20° C.]: −4.0 Δn [589 nm, 20° C.]: 0.12 Cp: 70° C. γ.sub.1: 78 mPa .Math. s

(30) The content of each liquid crystal compound in Example 1 is calculated based on the total content of the compounds represented by formula I, formula III, formula IV and formula V in the liquid crystal composition of Example 1 as being 100%.

Example 2

(31) The formulation and corresponding properties of the liquid crystal composition are as shown in table 4 below.

(32) TABLE-US-00004 TABLE 4 Formulation and corresponding properties of liquid crystal composition of Example 2 Category Liquid crystal monomer code Content (%) I CP-1-V 5 I CPP-1-2V1 4 I CCP-1-2V2 8 I CPY-2-V1 10 I CYY-3-1V1 12 I CCG-3-V2 11 II II5 0.1 II II8 0.2 II II11 0.2 III CC-2-3 22 III CC-3-V 9 III CC-5-3 8 III CCP-3-1 11 Performance S-N: ≤−40° C. parameters Δε [1 KHz, 20° C.]: −1.8 Δn [589 nm, 20° C.]: 0.09 Cp: 100° C. γ.sub.1: 75 mPa .Math. s

(33) The content of each liquid crystal compound in Example 2 is calculated based on the total content of the compounds represented by formula I and formula III in the liquid crystal composition of Example 2 as being 100%.

Example 3

(34) The formulation and corresponding properties of the liquid crystal composition are as shown in table 5 below.

(35) TABLE-US-00005 TABLE 5 Formulation and corresponding properties of liquid crystal composition of Example 3 Category Liquid crystal monomer code Content (%) I CP-2-1V1 11 I CCP-1-V 15 I CPP-3-2V1 12 I CCY-2-2V1 2 II II10 0.1 IV PY-3-O2 14 IV CY-3-O4 17 IV CCY-3-O4 4 IV CLY-3-O2 3 IV CPY-3-O2 5 IV PYP-2-3 8 IV PYP-2-4 9 Performance S-N: ≤−40° C. parameters Δε [1 KHz, 20° C.]: −2.8 Δn [589 nm, 20° C.]: 0.14 Cp: 80° C. γ.sub.1: 90 mPa .Math. s

(36) The content of each liquid crystal compound in Example 3 is calculated based on the total content of the compounds represented by formula I and formula IV in the liquid crystal composition of Example 3 as being 100%.

Example 4

(37) The formulation and corresponding properties of the liquid crystal composition are as shown in table 6 below.

(38) TABLE-US-00006 TABLE 6 Formulation and corresponding properties of liquid crystal composition of Example 4 Category Liquid crystal monomer code Content (%) I CP-2-1V1 8 I CCP-1-V 8 I CCP-5-V2 12 I CPP-3-2V1 11 I CPP-2-2V1 11 II II6 0.1 II II7 0.3 V Sa-2O-O5 10 V Sb-2O-O5 10 V Sa-O-O4 10 V Sc-Cpr1O-O4 10 V Sc-2O-O4 10 Performance S-N: ≤−40° C. parameters Δε [1 KHz, 20° C.]: −5.6 Δn [589 nm, 20° C.]: 0.15 Cp: 73° C. γ.sub.1: 130 mPa .Math. s

(39) The content of each liquid crystal compound in Example 4 is calculated based on the total content of the compounds represented by formula I and formula V in the liquid crystal composition of Example 4 as being 100%.

Example 5

(40) The formulation and corresponding properties of the liquid crystal composition are as shown in table 7 below.

(41) TABLE-US-00007 TABLE 7 Formulation and corresponding properties of liquid crystal composition of Example 5 Category Liquid crystal monomer code Content (%) I CP-1-1V1 10 I CP-3-V1 11 I CCP-2-1V1 7 I CPP-3-2V1 10 I CPP-5-V1 4 I CPP-3-V1 8 II II5 0.4 II II7 0.4 III CC-2-3 10 V Sa-5O -O2 6 V Sb-5O -O4 5 V Sa-Cp1O-O4 6 V Sc-2O -O4 8 V Sd-4O -O4 8 Performance S-N: ≤−40° C. parameters Δε [1 KHz, 20° C.]: −5.9 Δn [589 nm, 20° C.]: 0.14 Cp: 65° C. γ.sub.1: 86 mPa .Math. s

(42) The content of each liquid crystal compound in Example 5 is calculated based on the total content of the compounds represented by formula I, formula III and formula V in the liquid crystal composition of Example 5 as being 100%.

Example 6

(43) The formulation and corresponding properties of the liquid crystal composition are as shown in table 8 below.

(44) TABLE-US-00008 TABLE 8 Formulation and corresponding properties of liquid crystal composition of Example 6 Category Liquid crystal monomer code Content (%) I CP-1-1V1 8 I CCP-2-1V1 5 I CCP-3-2V1 4 I CPP-3-2V1 11 I CPP-5-V1 8 I CPP-3-V1 7 I CPY-4-V1 7 II II6 0.5 II II10 0.5 IV CPY-5-O2 1 V Sa-5O -O1 8 V Sb-5O -O2 7 V Sa-Cp1O-O4 6 V Sb-CprO-O4 8 V Sc-2O -O4 5 V Sd-4O -O4 4 V Sc-Cp1O-O4 6 V Sb-4O -O1 5 Performance S-N: ≤−40° C. parameters Δε [1 KHz, 20° C.]: −6.0 Δn [589 nm, 20° C.]: 0.16 Cp: 80° C. γ.sub.1: 120 mPa .Math. s

(45) The content of each liquid crystal compound in Example 6 is calculated based on the total content of the compounds represented by formula I, formula IV and formula V in the liquid crystal composition of Example 6 as being 100%.

Example 7

(46) The formulation and corresponding properties of the liquid crystal composition are as shown in table 9 below.

(47) TABLE-US-00009 TABLE 9 Formulation and corresponding properties of liquid crystal composition of Example 7 Category Liquid crystal monomer code Content (%) I CP-3-V1 6 I CCP-3-V1 9 I CPP-3-2V1 8 I CY-5-2V 7 II II5 0.3 III CC-4-3 16 III CC-2-3 3 III CC-5-3 5 III CCP-V-1 6 IV PY-3-O2 3 IV CY-3-O4 3 IV CCY-3-O4 12 IV CLY-3-O2 8 IV CPY-3-O2 11 IV PYP-2-3 3 Performance S-N: ≤−40° C. parameters Δε [1 KHz, 20° C.]: −2.7 Δn [589 nm, 20° C.]: 0.11 Cp: 98° C. γ.sub.1: 100 mPa .Math. s

(48) The content of each liquid crystal compound in Example 7 is calculated based on the total content of the compounds represented by formula I, formula III and formula IV in the liquid crystal composition of Example 7 as being 100%.

Example 8

(49) The formulation and corresponding properties of the liquid crystal composition are as shown in table 10 below.

(50) TABLE-US-00010 TABLE 10 Formulation and corresponding properties of liquid crystal composition of Example 8 Category Liquid crystal monomer code Content (%) I CPP-3-V1 7 I CPP-3-2V1 8 II II7 0.3 III CC-2-3 21 III CC-4-3 4 III CC-5-3 3 III PP-5-1 12 III CCP-3-1 4 IV CCY-3-O2 12 IV CCY-2-O2 3 IV CLY-3-O2 8 IV CPY-3-O2 10 IV CPY-2-O2 7 V Sa-5O -O2 1 Performance S-N: ≤−40° C. parameters Δε [1 KHz, 20° C.]: −2.5 Δn [589 nm, 20° C.]: 0.13 Cp: 113° C. γ.sub.1: 98 mPa .Math. s

(51) The content of each liquid crystal compound in Example 8 is calculated based on the total content of the compounds represented by formula I, formula III, formula IV and formula V in the liquid crystal composition of Example 8 as being 100%.

Comparative Example 1

(52) The formulation and corresponding properties of the liquid crystal composition are as shown in table 11 below.

(53) TABLE-US-00011 TABLE 11 Formulation and corresponding properties of liquid crystal composition of Comparative Example 1 Category Liquid crystal monomer code Content (%) Other CPP-5-2 7 Other CPP-3-2 8 II II7 0.3 III CC-2-3 21 III CC-4-3 4 III CC-5-3 3 III PP-5-1 12 III CCP-3-1 4 IV CCY-3-O2 12 IV CCY-2-O2 3 IV CLY-3-O2 8 IV CPY-3-O2 10 IV CPY-2-O2 7 V Sa-5O -O2 1 Performance S-N: ≤−40° C. parameters Δε [1 KHz, 20° C.]: −2.5 Δn [589 nm, 20° C.]: 0.12 Cp: 102° C. γ.sub.1: 112 mPa .Math. s

(54) The content of each liquid crystal compound in Comparative Example 1 is calculated based on the total content of the compounds represented by formula III, formula IV and formula V and other categories in the liquid crystal composition of Comparative Example 1 as being 100%.

(55) As can be seen from the comparison between Example 8 and Comparative Example 1, the liquid crystal composition provided in Example 8 has a larger Δn, a higher clearing point, and a lower rotary viscosity, so that the liquid crystal composition has a faster response speed. The compound represented by formula I has an alkenyl group, and the alkenyl group attached to the phenyl ring is more rigid than an alkyl group attached thereto. When the liquid crystal molecules rotate, segments are entangled with each other, and the alkyl group connected to the benzene ring has a stronger entangling than the case where the benzene ring is connected to an alkenyl, thereby affecting the rotation of the liquid crystal molecules, thereby making the liquid crystal molecules more rotationally viscous. Therefore, the rotary viscosity of the compound in which an alkenyl group is connected to the benzene ring is smaller, which is more advantageous for lowering the rotary viscosity of the liquid crystal composition and improving the response speed. When the liquid crystal composition is applied to a liquid crystal display element or a liquid crystal display, the response speed of the liquid crystal display element or liquid crystal display can be effectively improved.