CN103289708B - Positive dielectric anisotropic liquid crystal composition - Google Patents

Abstract

The invention discloses a positive dielectric anisotropic liquid crystal composition. The positive dielectric anisotropic liquid crystal composition comprises 1%-40% by weight of compound with a structural formula I, 1%-50% by weight of compound with a structural formula II, 1%-60% by weight of compound with a structural formula III and 1%-80% by weight of compound with a structural formula IV, and an optically active compound accounting for 0-0.5% of the total weight of the liquid crystal composition can be additionally added. The liquid crystal composition has the advantages of suitable positive dielectric anisotropy, lower rotary viscosity, very low total response time, lower voltage and higher resistivity and voltage holding ratio, and further has broad application prospects and application values in liquid crystal display.

Description

Positive dielectric anisotropy liquid crystal composition

technical field

The invention relates to a liquid crystal composition, in particular to a fast-response positive dielectric anisotropy liquid crystal composition which can be used for manufacturing TFT-LCD.

Background technique

Liquid Crystal Display Panel (Liquid Crystal Display Panel) has the characteristics of thinness, power saving and low radiation. It has gradually replaced traditional cathode ray tube display devices and is widely used in commercial and consumer electronics products. Liquid crystal display panels can be classified into passive matrix (PM) and active matrix (AM) according to the driving method. PM is divided into static (static) and multiplex (multiplex), etc. AM is currently mainly based on thin film transistors (TFT).

With the maturity of TFT technology in the early 1990s, color liquid crystal flat panel displays developed rapidly. In less than 10 years, TFT-LCD has rapidly grown into a mainstream display, which is inseparable from its advantages. Its advantages are mainly divided into five points: 1. Good use characteristics. Low-voltage application, low driving voltage; flat, light and thin, saving a lot of raw materials and space; low power consumption; display quality from the simplest monochrome character graphics to high resolution, high color fidelity, high brightness, high Various specifications and models of video displays with high contrast and high response speed; the display methods include direct-view, projection, see-through and reflective display methods. 2. Good environmental performance. TFT-LCD has no radiation, no flicker, and no harm to the health of users. Especially, the emergence of TFT-LCD electronic books will bring human beings into the era of paperless office and paperless printing, which will trigger human learning, dissemination and recording of civilization. way of revolution. 3. Wide application range: It can be used normally in the temperature range from -20°C to 50°C, and the low temperature working temperature of TFT-LCD after temperature strengthening treatment can reach minus 80°C. It can be used as a mobile terminal display, a desktop terminal display, and a large-screen projection TV. It is a full-size video display terminal with excellent performance. 4. High degree of automation in manufacturing technology. 5. TFT-LCD is easy to integrate and update.

As one of the important optoelectronic materials of liquid crystal display, liquid crystal material plays an important role in improving the performance of liquid crystal display. The liquid crystal materials used for display need to meet the following properties: (1) good chemical, physical and thermal stability, stability to electric field and electromagnetic radiation; (2) low viscosity (γ1); (3) suitable Dielectric anisotropy △ε; (4) Appropriate optical anisotropy △n; (5) Good compatibility with other liquid crystal compounds. As a liquid crystal material for TFT-LCD, it has higher requirements than ordinary liquid crystal materials. In addition to the above characteristics, it should also have a wide nematic phase temperature range, very high resistivity, good UV resistance, and high charge. Retention rate, low vapor pressure, low ion concentration, low power consumption, low rotational viscosity and other properties. However, due to the limitations of the liquid crystal material itself, TFT-LCD still has many defects such as slow response speed, high voltage, and low charge retention rate. Therefore, the continuous development of new liquid crystal materials with excellent performance is of great significance to the development of liquid crystal displays.

Contents of the invention

The technical problem to be solved in the present invention is to provide a positive dielectric anisotropy liquid crystal composition that can be used to prepare TFT-LCDs with high charge retention, high resistivity, high-definition bright spots, suitable optical anisotropy, and low rotational viscosity .

In order to solve the problems of the technologies described above, the technical solution adopted in the present invention is:

A liquid crystal composition with positive dielectric anisotropy, said liquid crystal composition comprising a compound of structural formula I, a compound of structural formula II, a compound of structural formula III and a compound of structural formula IV,

Wherein, _R1 is any one of the groups shown in the following ①～③:

①: -H, -Cl, -F, -CN, -OCN, -OCF ₃ , -CF ₃ , -CHF ₂ , -CH ₂ F, -OCHF ₂ , -SCN, -NCS, -SF ₅ , containing 1 Alkyl with 15 carbon atoms, alkoxy with 1 to 15 carbon atoms, alkenyl with 2 to 15 carbon atoms, alkenyloxy with 2 to 15 carbon atoms;

②: The alkyl group containing 1 to 15 carbon atoms, the alkoxy group containing 1 to 15 carbon atoms, the alkenyl group containing 2 to 15 carbon atoms, and the alkenyl group containing 2 to 15 carbon atoms mentioned in ① One or more -CH2- in the oxy group is replaced and replaced by -CH=CH-, -C≡C-, -COO-, -OOC-, cyclobutane, cyclopentane, -O- or -S- A group in which the oxygen atoms in the latter group are not directly connected;

③: An alkyl group containing 1 to 15 carbon atoms, an alkoxy group containing 1 to 15 carbon atoms, an alkenyl group containing 2 to 15 carbon atoms, and an alkyl group containing 2 to 15 carbon atoms as described in the above ① A group in which any H atom in an alkenyloxy group is replaced by a fluorine atom or a chlorine atom, or a group formed by replacing any H atom in the group described in ② above with a fluorine atom or a chlorine atom;

R ₂ , R ₃ , R ₄ , and R ₅ are -H, an alkyl group containing 1 to 10 carbon atoms, or an alkyl group containing 1 to 10 carbon atoms in which any -H is substituted by -F, or an alkyl group containing 1 to 10 carbon atoms. an alkoxy group containing 1 to 10 carbon atoms, or an alkoxy group containing 1 to 10 carbon atoms in which any -H is substituted by -F, an alkenyl group containing 2 to 10 carbon atoms, or an alkoxy group containing 2 carbon atoms in which any -H is substituted by -F Any of alkenyl groups with ~10 carbon atoms, alkenyloxy groups with 3 to 8 carbon atoms, or alkenyloxy groups with 3 to 8 carbon atoms where any -H is replaced by -F;

X ₁ , X ₂ , X ₃ , X ₄ , X ₅ , X ₆ , X ₇ are -H or -F respectively;

Z ₁ , Z ₂ , and Z ₃ are single bonds, -CH ₂ -, -CH ₂ -CH ₂ -, -(CH ₂ ) ₃ -, -(CH ₂ ) ₄ -, -CH=CH-, -C ≡C-, -COO-, -OOC-, -CF 2 O-, -OCH ₂ -, -CH ₂ O-, -OCF ₂ -, -CF ₂ CH ₂ -, -CH _{2 CF 2 -} , -CF Any one of ₂ -CF ₂ -, or -CF=CF-;

A ₁ , A ₂ , A ₃ , A ₄ , A ₆ , A ₇ , A ₈ , A ₉ , A ₁₀ , and A ₁₁ are each a single bond or any of the following groups:

_A5 can be selected from any one of the following groups:

a, b, d, e, f, h are any number of 0, 1, 2 or 3, c is any number of 1 or 2, and a+b+c≤5.

The weight percentage of the compound with the structural formula I is 1% to 40%, the weight percentage of the compound with the structural formula II is 1% to 50%, and the weight percentage of the compound with the structural formula III is 1% to 40%. 60%, the weight percentage of the compound with the structural formula IV is 1% to 80%; and the compound with the structural formula I, the compound with the structural formula II, the compound with the structural formula III, and the compound with the structural formula IV in the liquid crystal composition The sum of the weight percentages is 100%, on this basis, 0-0.5% of the total weight of the liquid crystal composition is added with an optically active compound.

Owing to adopting above-mentioned technical scheme, the technological progress that the present invention obtains is:

The positive dielectric anisotropy liquid crystal composition disclosed by the invention has proper positive dielectric anisotropy, suitable optical anisotropy, high charge retention rate, low rotational viscosity and very low total response time , lower voltage, higher resistivity and voltage retention, it has broad application prospects and application value in liquid crystal display.

The compound of the structural formula I and the compound of the structural formula II have the remarkable effect of increasing the dielectric anisotropy and reducing the response time, and have good high-temperature reliability. Among them, the compound with structural formula I has the necessary physical properties of liquid crystal monomer compounds, is stable to light and heat, has a wide nematic phase, and has good compatibility with other compounds, especially has low rotational viscosity and relatively low viscosity. The large dielectric anisotropy can effectively reduce the threshold voltage of the liquid crystal composition, reduce the response time at the same time, and improve the low-temperature mutual solubility of the liquid crystal composition.

By adjusting the weight percentage of each component in the liquid crystal composition, the liquid crystal composition can obtain different threshold voltages and birefringence characteristics, which is convenient for use under different liquid crystal cell thicknesses and different driving voltages, and has a very wide range of applications. At the same time, the liquid crystal composition also has excellent high temperature stability and ultraviolet stability, low viscosity, fast response time, appropriate optical anisotropy and appropriate dielectric anisotropy, so it can be applied to Optoelectronic displays, preferably addressed by a matrix of thin-film transistors (TFTs), are particularly suitable for the manufacture of fast-response active-matrix TN-TFT, IPS-TFT liquid crystal display elements and liquid crystal displays.

Detailed ways

Below in conjunction with embodiment the present invention is described in further detail:

The parts involved in the following examples are all percentages by weight, and the unit of temperature is ° C. The specific meanings and test conditions of other symbols are as follows:

C.p.: liquid crystal clearing point (°C), DSC quantitative method test;

Δn: optical anisotropy, n _o is the refractive index of ordinary light, ne _is the refractive index of extraordinary light, the test condition is 25±2°C, 589nm, tested by Abbe refractometer;

Δε: Dielectric anisotropy, Δε=ε∥-ε⊥, where ε∥ is the dielectric constant parallel to the molecular axis, ε⊥ is the dielectric constant perpendicular to the molecular axis, the test condition is 25±0.5℃, 20 micron parallel box, INSTEC: ALCT-IR1 test;

γ1: rotational viscosity (mPa s), the test condition is 25±0.5℃, 20 micron parallel box, INSTEC: ALCT-IR1 test;

ρ: Resistivity (Ω·cm), the test condition is 25±2°C, the test instrument is TOYOSR6517 megger and LE-21 liquid electrode.

VHR: Voltage retention rate, the test condition is 20±2°C, the voltage is ±5V, the pulse width is 10ms, and the voltage retention time is 16.7ms. The test equipment is TOYOModel6254 liquid crystal performance comprehensive tester.

V ₁₀ is the optical threshold voltage (V) of the liquid crystal, and V ₉₀ is the saturation voltage (V) of the liquid crystal.

VHR after UV: Put the liquid crystal mixture sample in the TN test box, and then test it after irradiating it with a UV lamp with an intensity of 50mw/cm ² and 365nm for 100s.

After high temperature ρ: The sample containing the liquid crystal mixture is placed in a high borosilicate glass bottle, heated at a high temperature of 100°C for 1 hour and then returned to room temperature for testing.

VHR after high temperature: The sample containing the liquid crystal mixture is put into a high borosilicate glass bottle, heated at a high temperature of 100°C for 1 hour, then returned to room temperature and poured into a TN test box for testing.

The positive dielectric anisotropy liquid crystal composition of the present invention comprises a compound with structural formula I, a compound with structural formula II, a compound with structural formula III and a compound with structural formula IV,

Wherein, _R1 is any one of the groups shown in the following ①～③:

①: -H, -Cl, -F, -CN, -OCN, -OCF ₃ , -CF ₃ , -CHF ₂ , -CH ₂ F, -OCHF ₂ , -SCN, -NCS, -SF ₅ , containing 1 Alkyl with 15 carbon atoms, alkoxy with 1 to 15 carbon atoms, alkenyl with 2 to 15 carbon atoms, alkenyloxy with 2 to 15 carbon atoms;

②: The alkyl group containing 1 to 15 carbon atoms, the alkoxy group containing 1 to 15 carbon atoms, the alkenyl group containing 2 to 15 carbon atoms, and the alkenyl group containing 2 to 15 carbon atoms mentioned in ① One or more -CH2- in the oxy group is replaced and replaced by -CH=CH-, -C≡C-, -COO-, -OOC-, cyclobutane, cyclopentane, -O- or -S- A group in which the oxygen atoms in the latter group are not directly connected;

③: An alkyl group containing 1 to 15 carbon atoms, an alkoxy group containing 1 to 15 carbon atoms, an alkenyl group containing 2 to 15 carbon atoms, and an alkyl group containing 2 to 15 carbon atoms as described in the above ① A group in which any H atom in an alkenyloxy group is replaced by a fluorine atom or a chlorine atom, or a group formed by replacing any H atom in the group described in ② above with a fluorine atom or a chlorine atom;

R ₂ , R ₃ , R ₄ , and R ₅ are -H, an alkyl group containing 1 to 10 carbon atoms, or an alkyl group containing 1 to 10 carbon atoms in which any -H is substituted by -F, or an alkyl group containing 1 to 10 carbon atoms. an alkoxy group containing 1 to 10 carbon atoms, or an alkoxy group containing 1 to 10 carbon atoms in which any -H is substituted by -F, an alkenyl group containing 2 to 10 carbon atoms, or an alkoxy group containing 2 carbon atoms in which any -H is substituted by -F Any of alkenyl groups with ~10 carbon atoms, alkenyloxy groups with 3 to 8 carbon atoms, or alkenyloxy groups with 3 to 8 carbon atoms where any -H is replaced by -F;

X ₁ , X ₂ , X ₃ , X ₄ , X ₅ , X ₆ , X ₇ are -H or -F respectively;

Z ₁ , Z ₂ , and Z ₃ are single bonds, -CH ₂ -, -CH ₂ -CH ₂ -, -(CH ₂ ) ₃ -, -(CH ₂ ) ₄ -, -CH=CH-, -C ≡C-, -COO-, -OOC-, -CF 2 O-, -OCH ₂ -, -CH ₂ O-, -OCF ₂ -, -CF ₂ CH ₂ -, -CH _{2 CF 2 -} , -CF Any one of ₂ -CF ₂ -, or -CF=CF-;

A ₁ , A ₂ , A ₃ , A ₄ , A ₆ , A ₇ , A ₈ , A ₉ , A ₁₀ , and A ₁₁ are each a single bond or any of the following groups:

_A5 can be selected from any one of the following groups:

a, b, d, e, f, h are any number of 0, 1, 2 or 3, c is any number of 1 or 2, and a+b+c≤5.

The ratio of the positive dielectric anisotropic liquid crystal composition of the present invention is: the weight percentage of the compound with structural formula I is 1% to 40%, preferably 5% to 35%; the weight percentage of the compound with structural formula II 1% to 50%, preferably 1% to 40%; the weight percentage of the compound with structural formula III is 1% to 60%, preferably 5% to 40%; the weight percentage of the compound with structural formula IV is 1% % to 80%, preferably 5% to 50%; and the sum of the weight percentages of the compound with structural formula I, the compound with structural formula II, the compound with structural formula III, and the compound with structural formula IV in the liquid crystal composition is 100%, on this basis, add 0-0.5% of the optically active compound based on the weight of the liquid crystal composition.

The composition of the positive dielectric anisotropy liquid crystal composition of the present invention is: the liquid crystal composition consists of 1 to 5 compounds with structural formula I, 1 to 6 compounds with structural formula II, and 1 to 5 compounds with structural formula III and 1 to 6 compounds of formula IV. Preferably, it consists of 1-4 compounds of formula I, 1-3 compounds of formula II, 1-5 compounds of formula III and 1-5 compounds of formula IV.

The performance parameters of the positive dielectric anisotropy liquid crystal composition of the present invention are: the rotational viscosity of the nematic phase of the liquid crystal composition is not more than 150mPa·s, preferably not more than 100mPa·s, and the dielectric properties at 25°C and 1kHz are The anisotropy Δε is between 1 and 15, preferably between 3 and 12, and the birefringence Δn is lower than 0.15, preferably between 0.05 and 0.13, more preferably between 0.08 and 0.12.

The compound of the present invention having structural formula I, the compound of structural formula II, the compound of structural formula III, the preferred structure of the compound of structural formula IV is as follows:

Among them, R ₃ , R ₄ , and R ₅ are respectively an alkyl group containing 1 to 10 carbon atoms or an alkyl group containing 1 to 10 carbon atoms in which any -H is substituted by -F, or an alkyl group containing 1 to 10 carbon atoms. Alkoxy or an alkoxy group containing 1 to 10 carbon atoms in which any -H is substituted by -F, an alkenyl group containing 2 to 10 carbon atoms or an alkoxy group containing 2 to 10 carbon atoms in which any -H is substituted by -F Atomic alkenyl, alkenyloxy containing 3 to 8 carbon atoms, or any group of alkenyloxy containing 3 to 8 carbon atoms in which any -H is substituted by -F; -(F) is -H or -F.

In Examples 1-10 below, the compounds with structural formulas I, II, III, and IV were weighed in proportion, and optically active compounds were added on this basis to prepare liquid crystal compositions. Various liquid crystal monomers used can be synthesized by known methods, or can be obtained commercially. The preparation method of the liquid crystal composition adopts a conventional method, such as dissolving liquid crystal monomers of various components in a solvent at high temperature for mixing, and then distilling off the solvent under reduced pressure to obtain a liquid crystal composition; or adopting ultrasonic waves, suspending and other methods to mix the liquid crystal monomers in proportion. The obtained liquid crystal composition is filled between the two substrates of the liquid crystal display for performance testing. The type number, monomer structure, dosage (weight percentage) of the specific compound, and the performance parameter test results of the obtained liquid crystal composition are all listed in the table. Tables 1-10 correspond to Examples 1-10.

Example 1

The proportioning and performance parameter of the liquid crystal composition of table 1 embodiment 1

Example 2

Table 2 Liquid crystal composition ratio and performance parameters of Example 2

Example 3

Table 3 Liquid crystal composition ratio and performance parameters of Example 3

Example 4

The ratio and performance parameters of the liquid crystal composition of Table 4 Example 4

Example 5

The ratio and performance parameters of the liquid crystal composition of Table 5 Example 5

Example 6

The ratio and performance parameters of the liquid crystal composition of Table 6 Example 6

Example 7

The ratio and performance parameters of the liquid crystal composition of Table 7 Example 7

Example 8

The ratio and performance parameters of the liquid crystal composition of Table 8 Example 8

Example 9

Table 9 The ratio and performance parameters of the liquid crystal composition of Example 9

Example 10

The ratio and performance parameters of the liquid crystal composition of Table 10 Example 10

The liquid crystal mixtures in the above 10 examples have high clearing point, low rotational viscosity, wide temperature range of nematic phase, proper dielectric anisotropy, fast response time and high high temperature and ultraviolet Reliable, and has relatively low cost, at the same time has high resistivity and voltage retention rate, high stability, can provide a very wide range of application directions, especially suitable for manufacturing fast response TN-TFT, IPS - TFT liquid crystal display elements and liquid crystal displays.

Although the present invention only enumerates the specific compounds and proportioning mass percentages of the above-mentioned 10 embodiments, and has carried out performance tests, the liquid crystal composition of the present invention can be used on the basis of the above-mentioned embodiments. The compounds represented by the general formulas I, II, III, and IV, as well as the preferred compounds of the general formulas I, II, III, and IV, can be further expanded and modified to achieve the object of the present invention. These modifications or improvements made on the basis of not departing from the technical idea of the present invention all belong to the protection scope of the present invention.

Claims (6)

1. A positive dielectric anisotropic liquid crystal composition, characterized in that: the liquid crystal composition consists of a compound with a structural formula I, a compound with a structural formula II, a compound with a structural formula III and a compound with a structural formula IV,

the weight percentage of the compound with the structural formula I is 5-35%, the weight percentage of the compound with the structural formula II is 1-40%, the weight percentage of the compound with the structural formula III is 5-40%, and the weight percentage of the compound with the structural formula IV is 5-50%; the sum of the weight percentages of the compound with the structural formula I, the compound with the structural formula II, the compound with the structural formula III and the compound with the structural formula IV in the liquid crystal composition is 100 percent, and an optical activity compound accounting for 0-0.5 percent of the sum of the weight percentages of the liquid crystal composition is added;

the compound with the structural formula I is a compound shown as I-a to I-v:

the compound with the structural formula II is a compound shown in II-a-II-l:

the compound with the structural formula III is a compound shown in III-a-III-m:

the compound with the structural formula IV is a compound shown as IV-a-IV-w:

wherein,

R₁is any one of the following groups shown in (i) - (iii):

①：-H、-Cl、-F、-CN、-OCN、-OCF₃、-CF₃、-CHF₂、-CH₂F、-OCHF₂、-SCN、-NCS、-SF₅an alkyl group having 1 to 15 carbon atoms, an alkoxy group having 1 to 15 carbon atoms, an alkenyl group having 2 to 15 carbon atoms, an alkenyloxy group having 2 to 15 carbon atoms;

secondly, the step of: a group wherein one or more-CH 2-groups selected from the group consisting of an alkyl group having 1 to 15 carbon atoms, an alkoxy group having 1 to 15 carbon atoms, an alkenyl group having 2 to 15 carbon atoms and an alkenyloxy group having 2 to 15 carbon atoms are replaced by-CH-CH-, -C.ident.C-, -COO-, -OOC-, cyclobutane, cyclopentane, -O-and-S-and wherein the oxygen atoms in the group after the replacement are not directly linked to each other;

③: a group wherein any H atom in the alkyl group having 1 to 15 carbon atoms, the alkoxy group having 1 to 15 carbon atoms, the alkenyl group having 2 to 15 carbon atoms, and the alkenyloxy group having 2 to 15 carbon atoms described in the above formula is substituted with a fluorine atom or a chlorine atom, or a group wherein any H atom in the above formula is substituted with a fluorine atom or a chlorine atom;

R₂is-H, alkyl having 1 to 10 carbon atoms or-H optionally substituted by-F and having 1 to 10 carbon atomsAny one of an alkyl group, an alkoxy group having 1 to 10 carbon atoms or an alkoxy group having 1 to 10 carbon atoms optionally substituted with-F, an alkenyl group having 2 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms optionally substituted with-F, an alkenyloxy group having 3 to 8 carbon atoms or an alkenyloxy group having 3 to 8 carbon atoms optionally substituted with-F;

R₃、R₄、R₅each of which is any one of an alkyl group having 1 to 10 carbon atoms or an alkyl group having 1 to 10 carbon atoms optionally substituted by-F, an alkoxy group having 1 to 10 carbon atoms or an alkoxy group having 1 to 10 carbon atoms optionally substituted by-F, an alkenyl group having 2 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms optionally substituted by-F, an alkenyloxy group having 3 to 8 carbon atoms or an alkenyloxy group having 3 to 8 carbon atoms optionally substituted by-F; - (F) is-H or-F.

2. The positive dielectric anisotropic liquid crystal composition according to claim 1, wherein: the liquid crystal composition is composed of 1-5 compounds with a structural formula I, 1-6 compounds with a structural formula II, 1-5 compounds with a structural formula III and 1-6 compounds with a structural formula IV.

3. The positive dielectric anisotropic liquid crystal composition according to claim 2, wherein: the liquid crystal composition is composed of 1-4 compounds with a structural formula I, 1-3 compounds with a structural formula II, 1-5 compounds with a structural formula III and 1-5 compounds with a structural formula IV.

4. The positive dielectric anisotropic liquid crystal composition according to claim 1, wherein: the liquid crystal composition has a nematic phase rotational viscosity of not more than 150mPa · s, a dielectric anisotropy delta of 1-15 at 25 ℃ and lkHz, and a birefringence delta n of less than 0.15.

5. The positive dielectric anisotropic liquid crystal composition according to claim 4, wherein: the nematic rotational viscosity of the liquid crystal composition is preferably not more than 100 mPas; the dielectric anisotropy delta is between 3 and 12 at the temperature of 25 ℃ and the lkHz; the birefringence Deltan is between 0.05 and 0.13.

6. The positive dielectric anisotropic liquid crystal composition according to claim 5, wherein: the birefringence Deltan is between 0.08 and 0.12.