TWI797047B - Negative dielectric anisotropy liquid crystal composition, optical anisotropy and liquid crystal display device - Google Patents

Abstract

The invention relates to a liquid crystal composition with negative dielectric anisotropy, an optical anisotropy and a liquid crystal display device. The negative dielectric anisotropy liquid crystal composition of the present invention comprises: at least one compound represented by formula I, at least one compound represented by formula II and at least one compound represented by formula III. Compared with the prior art, the liquid crystal composition of the present invention obtains good low-temperature preservation and faster polymerization rate on the basis of maintaining appropriate optical anisotropy value and dielectric anisotropy, and further takes into account higher Reliability and poor display caused by changes in pretilt angle are not easy to occur.

Description

Negative dielectric anisotropy liquid crystal composition, optical anisotropy and liquid crystal display device

The invention relates to the technical field of liquid crystal materials. More specifically, it relates to liquid crystal compositions, optical anisotropes, and liquid crystal display devices.

In liquid crystal display devices, pixels are usually made into multiple domains to improve visual characteristics, so protrusions and the like are provided to divide the pixels. However, when the protrusion is provided, there is a difference in pretilt angle between the vicinity of the protrusion and the separation part, resulting in a decrease in the response speed of the separation part.

Afterwards, a PSA (Polymer Sustained Alignment) liquid crystal display device and a PSVA (Polymer Stabilized Vertical Alignment) liquid crystal display device were developed. In a PSA or PSVA liquid crystal display device, a non-polymeric liquid crystal composition and a polymeric compound are disposed between substrates, and a voltage is optionally applied between the substrates to align the liquid crystal molecules. In the aligned state, the polymerizable compound is polymerized by irradiation with ultraviolet light or the like, and the aligned state of the liquid crystal is stored in the cured product.

Such liquid crystal display devices still have problems in reliability such as "image sticking" when the same display is continued for a long time, storage stability, productivity due to manufacturing process, and the like.

With regard to reliability, when a polymerization initiator is used, the polymerization initiator and its decomposition products cause a decrease in the voltage retention ratio of the liquid crystal display device and cause image sticking. In addition, it is also known that the occurrence of image sticking is also related to the change in the pretilt angle of liquid crystal molecules in a liquid crystal composition containing a polymerizable compound. That is, if the polymer that is the cured product of the polymerizable compound is flexible, when the same pattern is continuously displayed for a long time when forming a display device, the polymer structure changes, and as a result, the pretilt angle changes, and an excellent pretilt angle greatly affects the response speed , thereby affecting the reliability of the display. Therefore, in order to solve the pre- As for the problem of changing the inclination angle, it is effective to form a polymerizable compound of a polymer having a rigid structure in which the polymer structure does not change, but in this case, there is a problem that the low-temperature storage property of the liquid crystal composition deteriorates.

Therefore, there is a need to develop a liquid crystal composition containing a polymerizable compound that achieves both low-temperature storage stability and improved productivity of the manufacturing process. In addition, there is a demand for a liquid crystal composition containing a polymerizable compound that solves reliability problems such as "image sticking" that occurs when the same display is continued for a long period of time.

An object of the present invention is to provide a liquid crystal composition containing a polymerizable compound, which has an excellent polymerization reaction rate, thereby improving the productivity of the manufacturing process, and having low-temperature storage stability.

Further, when the liquid crystal composition of the present invention is used in PSA, PSVA display device, can obtain the VHR value after the ultraviolet ray irradiation that improves, thereby can reduce/eliminate the defect of poor display such as " afterimage " of liquid crystal display device, reliability improve.

The inventors of the present invention conducted intensive studies to solve the above-mentioned problems, found that the above-mentioned problems can be solved by using the negative dielectric anisotropy liquid crystal composition of the present application, and completed the present invention.

One aspect of the present invention provides a liquid crystal composition with negative dielectric anisotropy, which comprises: at least one compound represented by formula I; at least one compound represented by formula II; and at least one compound represented by formula III;

In formula I, P ₁ and P ₂ each independently represent an acrylate group, a methacrylate group, an ethacrylate group, a propyl acrylate group, a butyl acrylate group, an amyl acrylate group, a fluoroacrylic acid group ester group, fluoromethacrylate group, fluoroethylacrylate group, fluoropropylacrylate group, fluorobutylacrylate group or fluoropentylacrylate group; Z ₁ and Z ₂ are independent means a single bond, a straight-chain alkylene group with 1 to 8 carbon atoms, a straight-chain alkyleneoxy group with 1 to 8 carbon atoms, a straight-chain alkenylene group with 2 to 8 carbon atoms, or a carbon Straight-chain alkenyleneoxy groups with 2~8 atoms, one or two non-adjacent -CH ₂ - are optionally substituted by -O-, any H is optionally substituted by F atom; Y ₁ , Y ₂ , Y ₃ , Y ₄ , Y ₅ , Y ₆ , Y ₇ , Y ₈ , Y ₉ , and Y ₁₀ each independently represent -H, -F, -CH ₃ , -CH ₂ F, -CHF ₂ , -CF ₃ , -C ₂ H ₅ , -OCH ₃ , -OCH ₂ F, -OCHF ₂ , -OCF ₃ or -OC ₂ H ₅ ; n represents 0, 1 or 2; in formula II, R ₃ and R ₄ are each independently represents an alkyl group with 1 to 5 carbon atoms, an alkoxy group with 1 to 5 carbon atoms, an alkenyl group with 2 to 5 carbon atoms, or an alkenyloxy group with 2 to 5 carbon atoms; and, H on any carbon atom in R ₃ and R ₄ is independently optionally substituted by F; ring C and ring D are each independently selected from the group consisting of the following groups: 1,4-cyclohexylene, cyclohexyl En-1,4-diyl, 1,4-phenylene, 2-fluoro-1,4-phenylene, 2,3-difluoro-1,4-phenylene, oxane- 2,5-diyl, 1,3-dioxane-2,5-diyl, 1-methylcyclohexane-1,4-diyl, 2-methylcyclohexane-1, 4-diyl, 2-methylbenzene-1,4-diyl; p represents 0, 1, 2 or 3; in formula III, R ₅ and R ₆ each independently represent an alkane with 1 to 5 carbon atoms group, an alkoxy group with 1 to 5 carbon atoms, an alkenyl group with 2 to 5 carbon atoms, or an alkenyloxy group with 2 to 5 carbon atoms; and, on any carbon atom in R ₅ and R ₆ H in each independently optionally substituted by F; Z ₃ represents a single bond or -CH ₂ O-; q, r independently represent 0, 1 or 2; ring E, ring F are each independently selected from the following groups Group consisting of: 1,4-cyclohexylene, cyclohexene-1,4-diyl, 1,4-phenylene, 2-fluoro-1,4-phenylene, 2,3-difluoro -1,4-phenylene, oxane-2,5-diyl, 1,3-dioxane-2,5-diyl, 1-methylcyclohexane-1, 4-diyl, 2-methylcyclohexane-1,4-diyl, 2-methylbenzene-1,4-diyl.

In another aspect, the present invention provides an optical anisotropy consisting of the aforementioned negative dielectric anisotropy Polymer composition of anisotropic liquid crystal composition.

In yet another aspect, the present invention provides a liquid crystal display device, which uses the above-mentioned negative dielectric anisotropy liquid crystal composition, and polymerizes the polymerizable compound in the negative dielectric anisotropy liquid crystal composition to give liquid crystal alignment performance liquid crystal display devices.

The negative dielectric anisotropy liquid crystal composition of the present invention has excellent polymerization reaction rate and low-temperature storage stability. Further, when the liquid crystal composition of the present invention is used in liquid crystal display devices of modes such as PSA and PSVA, the VHR value after ultraviolet irradiation can be obtained to be improved, thereby reducing/eliminating the defects of poor display such as "image sticking" of the liquid crystal display device. defect. The optical anisotropy of the present invention composed of the polymer of the negative dielectric anisotropy liquid crystal composition of the present invention has little remaining polymer, has a stable pretilt angle, and has good low-temperature storage stability. In the liquid crystal display device of the present invention, the productivity of the manufacturing process is improved, and defects such as "image sticking" and other display defects are reduced.

[Liquid Crystal Composition]

The negative dielectric anisotropy liquid crystal composition of the present invention comprises: at least one compound represented by formula I; at least one compound represented by formula II; and at least one compound represented by formula III.

In formula I, P ₁ and P ₂ each independently represent a polymerizable group, as the polymerizable group, the following groups can be listed: acrylate group, methacrylate group, ethacrylate group, propyl group Acrylate, Butylacrylate, Amylacrylate, Fluoroacrylate, Fluoromethacrylate, Fluoroethylacrylate, Fluoropropylacrylate, Fluorobutyl Acrylate or fluoropentyl acrylate.

The aforementioned "fluoro" can be monofluoro, polyfluoro, or perfluoro.

These groups are cured by radical polymerization, radical addition polymerization, cationic polymerization, anionic polymerization, and the like. Especially in the case of ultraviolet polymerization, it is preferable that P ₁ and P ₂ each independently represent an acrylate group or a methacrylate group.

In formula I, Z ₁ and Z ₂ each independently represent a single bond, a straight-chain alkylene group with 1 to 8 carbon atoms, a straight-chain alkyleneoxy group with 1 to 8 carbon atoms, and a straight-chain alkyleneoxy group with 2 carbon atoms. ~8 straight-chain alkenylene groups, or straight-chain alkenyleneoxy groups with 2~8 carbon atoms, wherein one or two non-adjacent -CH ₂ -s are optionally substituted by -O-, and any H is any is substituted by an F atom. Preferably, Z ₁ and Z ₂ each independently represent a single bond, a straight-chain alkylene group with 1 to 5 carbon atoms, a straight-chain alkyleneoxy group with 1 to 5 carbon atoms, and a straight-chain alkyleneoxy group with 2 to 5 carbon atoms. 5 straight-chain alkenylene groups, or straight-chain alkenyleneoxy groups with 2 to 5 carbon atoms, wherein one or two non-adjacent -CH ₂ - are optionally substituted by -O-, and any H is optionally replaced by an F atom. Further preferably, Z ₁ and Z ₂ each independently represent a single bond, a straight-chain alkylene group with 1 to 3 carbon atoms, a straight-chain alkyleneoxy group with 1 to 3 carbon atoms, and a straight-chain alkyleneoxy group with 2 carbon atoms. ~4 straight-chain alkenylene groups, or straight-chain alkenyleneoxy groups with 2~4 carbon atoms, wherein one or two non-adjacent -CH ₂ -s are optionally substituted by -O-, and any H is any is substituted by an F atom.

Examples of the aforementioned "straight-chain alkylene group having 1 to 3 carbon atoms" include methylene group, ethylene group, and propylene group. Examples of the "straight-chain alkyleneoxy group having 1 to 3 carbon atoms" include methyleneoxy, ethyleneoxy, and propyleneoxy. Examples of the "straight-chain alkenylene group having 2 to 3 carbon atoms" include vinylene, propenylene and butenylene. Examples of the "straight-chain alkenyleneoxy group having 2 to 4 carbon atoms" include vinyleneoxy, propenyleneoxy, butenyleneoxy and the like. One or two non-adjacent -CH ₂ -s in these groups are optionally substituted by -O-, and any H is optionally substituted by F atoms.

Among the aforementioned compounds represented by formula I, Y ₁ , Y ₂ , Y ₃ , Y ₄ , Y ₅ , Y ₆ , Y ₇ , Y ₈ , Y ₉ , and Y ₁₀ each independently represent -H, -F, -CH _3. -CH ₂ F, -CHF ₂ , -CF ₃ , -C ₂ H ₅ , -OCH ₃ , -OCH ₂ F, -OCHF ₂ , -OCF ₃ or -OC ₂ H ₅ . Wherein, Y ₁ and Y ₂ are optionally the same or different.

In some embodiments of the negative dielectric anisotropy liquid crystal composition of the present invention, preferably, Y ₁ and Y ₂ in the compound represented by formula I each independently represent -H, -F, -CH ₃ , -CF ₃ , -OCH ₃ , -C ₂ H ₅ , -OC ₂ H ₅ or -OCF ₃ . More preferably, Y ₁ and Y ₂ each independently represent -H, -F, -CF ₃ , or -OCF ₃ . More preferably, Y ₁ and Y ₂ are each independently -H or -F.

In some embodiments of the negative dielectric anisotropy liquid crystal composition of the present invention, preferably, Y ₃ , Y ₄ , Y ₅ , Y ₆ , Y ₇ , Y ₈ , Y ₉ , Y ₁₀ in the compound represented by formula I Indicates -H or -F. More preferably, Y ₃ , Y ₄ , Y ₅ , Y ₆ , Y ₇ , Y ₈ , Y ₉ , and Y ₁₀ are all -H.

In some embodiments of the liquid crystal composition with negative dielectric anisotropy of the present invention, n is preferably 0 or 1, more preferably n=1, in view of obtaining a faster polymerization reaction rate and the like.

In some embodiments of the negative dielectric anisotropy liquid crystal composition of the present invention, it is preferred that the compound represented by formula I is selected from the group consisting of compounds represented by the following formulas I-1 to I-57, wherein P ₁ , P _2. The definitions of Z ₁ and Z ₂ are the same as above.

Further, the compound represented by the aforementioned formula I is preferably selected from the group consisting of compounds represented by the following formulas IA-1 to IA-258.

In the liquid crystal composition of the present invention, the structural formula of the compound represented by the aforementioned formula II is as follows.

In formula II, R ₃ and R ₄ each independently represent an alkyl group with 1 to 5 carbon atoms, an alkoxy group with 1 to 5 carbon atoms, an alkenyl group with 2 to 5 carbon atoms, or a carbon atom Alkenyloxy groups with a number of 2 to 5; and, H on any carbon atom in R ₃ and R ₄ is independently optionally substituted by F; ring C and ring D are each independently selected from the following groups: Groups: 1,4-cyclohexylene, cyclohexene-1,4-diyl, 1,4-phenylene, 2-fluoro-1,4-phenylene, 2,3-difluoro-1, 4-phenylene, oxane-2,5-diyl, 1,3-dioxane-2,5-diyl, 1-methylcyclohexane-1,4-diyl base, 2-methylcyclohexane-1,4-diyl, 2-methylbenzene-1,4-diyl; p represents 0, 1, 2 or 3.

The "alkyl group having 1 to 5 carbon atoms" independently represented by the aforementioned R ₃ and R ₄ may be a straight-chain alkyl group, a branched-chain alkyl group or a cyclic alkyl group, and is preferably a straight-chain alkyl group. Examples of such straight-chain alkyl groups include methyl groups, ethyl groups, n-propyl groups, n-butyl groups, and n-pentyl groups. As a branched alkyl group, an isopropyl group, an isobutyl group, a tert-butyl group etc. are mentioned, for example. Cyclopropyl, cyclobutyl, cyclopentyl, methylcyclopropyl, methylcyclobutyl etc. are mentioned as a cyclic alkyl group.

Examples of the "alkoxy group having 1 to 5 carbon atoms" each independently represented by R ₃ and R ₄ above include methoxy, ethoxy, n-propoxy, isopropoxy, n- Butoxy, isobutoxy, n-pentoxy, tert-pentoxy, etc.

Examples of the "alkenyl group having 2 to 5 carbon atoms" each independently represented by R ₃ and R ₄ above include vinyl, propenyl, butenyl, 2-methacryl, 1-pentyl Alkenyl, 2-pentenyl, 2-methyl-1-butenyl, 3-methyl-1-butenyl, 2-methyl-2-butenyl and the like.

Examples of the "alkenyloxy group having 2 to 5 carbon atoms" each independently represented by _R3 and _R4 above include ethyleneoxy, propyleneoxy, butenyloxy, 2-methacryloxy, Base, 1-pentenyloxy, 2-pentenyloxy, 2-methyl-1-butenyloxy, 3-methyl-1-butenyloxy, 2-methyl-2-butenyloxy Base etc.

The compound represented by the aforementioned formula II is preferably selected from the group consisting of compounds represented by the following formulas II-1 to II-11. Wherein, the definitions of R ₃ and R ₄ are the same as above.

(F) means F or H.

In the liquid crystal composition of the present invention, the structural formula of the compound represented by the aforementioned formula III is as follows.

In formula III, R ₅ and R ₆ each independently represent an alkyl group with 1 to 5 carbon atoms, an alkoxy group with 1 to 5 carbon atoms, an alkenyl group with 2 to 5 carbon atoms, or a carbon atom The number is 2-5 alkenyloxy groups; and, the H on any carbon atom in R ₅ and R ₆ is independently optionally substituted by F; Z ₃ represents a single bond or -CH ₂ O-; q and r are independently means 0, 1 or 2; ring E and ring F are each independently selected from the group consisting of the following groups: 1,4-cyclohexylene, cyclohexene-1,4-diyl, 1,4- Phenylene, 2-fluoro-1,4-phenylene, 2,3-difluoro-1,4-phenylene, oxane-2,5-diyl, 1,3-dioxo Heterocyclohexane-2,5-diyl, 1-methylcyclohexane-1,4-diyl, 2-methylcyclohexane-1,4-diyl, 2-methylbenzene-1, 4-diradical.

The "alkyl group having 1 to 5 carbon atoms" independently represented by the aforementioned R ₅ and R ₆ may be a straight-chain alkyl group, a branched-chain alkyl group or a cyclic alkyl group, and is preferably a straight-chain alkyl group. Examples of such straight-chain alkyl groups include methyl groups, ethyl groups, n-propyl groups, n-butyl groups, and n-pentyl groups. As a branched alkyl group, an isopropyl group, an isobutyl group, a tert-butyl group etc. are mentioned, for example. Cyclopropyl, cyclobutyl, cyclopentyl, methylcyclopropyl, methylcyclobutyl etc. are mentioned as a cyclic alkyl group.

Examples of the "alkoxy group having 1 to 5 carbon atoms" each independently represented by R ₅ and R ₆ above include methoxy, ethoxy, n-propoxy, isopropoxy, n- Butoxy, isobutoxy, n-pentoxy, tert-pentoxy, etc.

Examples of the "alkenyl group having 2 to 5 carbon atoms" each independently represented by the aforementioned R ₅ and R ₆ include vinyl, propenyl, butenyl, 2-methacryl, 1-pentyl Alkenyl, 2-pentenyl, 2-methyl-1-butenyl, 3-methyl-1-butenyl, 2-methyl-2-butenyl and the like.

Examples of the "alkenyloxy group having 2 to 5 carbon atoms" each independently represented by R ₅ and R ₆ above include ethyleneoxy, propyleneoxy, butenyloxy, 2-methacryloxy, Base, 1-pentenyloxy, 2-pentenyloxy, 2-methyl-1-butenyloxy, 3-methyl-1-butenyloxy, 2-methyl-2-butenyloxy Base etc.

Preferably, the compound represented by the aforementioned formula III is selected from the group consisting of the compounds represented by the following formulas III-1 to III-17. Wherein, the definitions of R ₅ and R ₆ are the same as above.

In one embodiment of the foregoing negative dielectric anisotropy liquid crystal composition, the compound represented by formula I, the compound represented by formula II, and the compound represented by formula III can be contained in the following ratio, for example: relative to 100 parts by mass of the liquid crystal composition , the compound represented by the formula I is 0.001-1 parts by mass, the compound represented by the formula II is 10-60 parts by mass, and the compound represented by the formula III is 10-70 parts by mass.

In some embodiments of the negative dielectric anisotropy liquid crystal composition of the present invention, compounds represented by the following formulas IV-1 to IV-50 may also be included.

Among them, R ₁ ' represents H or an alkyl group with 1 to 8 carbon atoms or an alkenyl group with 2 to 8 carbon atoms, and optionally 4 or less Hs are replaced by F; R ₂ ' represents H or carbon atoms An alkyl group of 1 to 8 or an alkenyl group with a carbon number of 2 to 8, wherein one or two non-adjacent -CH ₂ -s are optionally substituted by -O-, and optionally 4 or less Hs are replaced by F replace.

In some embodiments of the negative dielectric anisotropy liquid crystal composition of the present invention, each component may be contained in the following mass ratio: relative to 100 parts by mass of the negative dielectric anisotropy liquid crystal composition, the aforementioned formula I 0.001-0.3 parts by mass of the compound shown, 20-60 parts by mass of the compound shown in the aforementioned formula II, 20-60 parts by mass of the compound shown in the aforementioned formula III, and 1-20 parts by mass of the compound shown in the aforementioned formula IV.

In some embodiments of the negative dielectric anisotropy liquid crystal composition of the present invention, it may also optionally contain one or more compounds represented by the following formulas V-1~V-78:

In some embodiments of the negative dielectric anisotropy liquid crystal composition of the present invention, when containing the compound represented by the aforementioned formula V, each component can be contained according to the following mass ratio: relative to 100 parts by mass of negative Dielectrically anisotropic liquid crystal composition, the compound shown in the aforementioned formula I is 0.001~0.3 parts by mass, the compound shown in the aforementioned formula II is 20~60 parts by mass, the compound shown in the aforementioned formula III is 20~60 parts by mass, the compound shown in the aforementioned formula The compound represented by IV is 1 to 20 parts by mass, and the compound represented by the aforementioned formula V is 1 to 10 parts by mass.

In the negative dielectric anisotropy liquid crystal composition of the present invention, optionally, additives of various functions can also be added, and these additives can enumerate such as UV stabilizers, antioxidants, chiral dopants, polymerization initiators, One or more of them may be included.

[Optical anisotropes]

The optical anisotropy of the present invention is polymerized by using the negative dielectric anisotropy liquid crystal composition of the present invention. The aforementioned optical anisotropy is produced by polymerizing the polymerizable compound in the negative dielectrically anisotropic liquid crystal composition of the present invention in an aligned state. The optical anisotropy of the present invention has optical anisotropy. Such an optical anisotropy can be produced, for example, by sandwiching the negative dielectric anisotropy liquid crystal composition of the present invention between substrates on which the surface of the substrate on which the organic thin film is formed is rubbed with cloth or the like, and then making the composition The inventive liquid crystal composition is polymerized.

In addition, when the orientation state is controlled by an electric field, a substrate having an electrode layer can be used. In this case, it is preferable to form an organic thin film such as a polyimide thin film on the electrode.

As a method of polymerizing the liquid crystal composition of the present invention, a method of polymerizing by irradiating active energy rays such as ultraviolet rays and electron beams is preferable from the viewpoint of rapid polymerization. When superposing|polymerizing in the state which sandwiched a liquid crystal polymer between two board|substrates, at least the board|substrate of an irradiation surface side is made transparent to an active energy ray. The irradiation intensity and time of active energy rays may be appropriately determined as needed.

The optical anisotropy of the present invention produced by such a method may be used alone after peeling off the substrate, or may be used without peeling off. In addition, it can also be used by bonding it to other substrates.

[Liquid crystal display device]

The liquid crystal display device of the present invention is a liquid crystal display device provided with liquid crystal alignment performance by polymerizing a polymerizable compound in the negative dielectric anisotropy liquid crystal composition using the above-mentioned negative dielectric anisotropy liquid crystal composition of the present invention.

The driving mode of the liquid crystal display device of the present invention is preferably, for example, PS-VA mode, PVA mode, or, or PS-IPS mode.

Example

In order to illustrate the present invention more clearly, the present invention will be further described below in conjunction with preferred embodiments. Those skilled in the art should understand that the content specifically described below is illustrative rather than restrictive, and should not limit the protection scope of the present invention.

The following preparation methods are conventional methods unless otherwise specified, and the raw materials used can be obtained from public commercial sources unless otherwise specified, and the percentages refer to mass percentages, the temperature is degrees Celsius (°C), and the liquid crystal compound is also a liquid crystal monomer.

Negative dielectric anisotropy liquid crystal compositions of different compositions were prepared in the examples and comparative examples, wherein, the monomer structure, dosage (mass parts) of the specific compounds used in each example, and the performance parameter test of the obtained liquid crystal medium The results are shown in the tables described later.

The unit of temperature involved in each embodiment is °C, and the specific meanings and test conditions of other symbols are as follows: G1 (mPa.s) represents the rotational viscosity coefficient of the liquid crystal compound, and the measurement method: Instrument and equipment INSTEC: ALCT-IR1, test box 18 micron thick vertical box, temperature 25°C, abbreviated as "G1"; K ₁₁ is the torsional elastic constant, K ₃₃ is the spread elastic constant, the test conditions are: 25°C, INSTEC: ALCT-IR1, 18 micron vertical box; △ ε means dielectric anisotropy, △ε=ε _∥ -ε _⊥ , where ε _∥ is the dielectric constant parallel to the molecular axis, ε _⊥ is the dielectric constant perpendicular to the molecular axis, test conditions: 25℃, INSTEC : ALCT-IR1, 18 micron vertical cell; △n represents optical anisotropy, △n=n _e -n _o , where, n _o is the refractive index of ordinary light, ne _is the refractive index of extraordinary light, test conditions : 589nm, 25±0.2°C.

Tni: nematic phase-isotropic liquid phase transition temperature (° C.).

Low-temperature storage stability: After cooling the examples of the liquid crystal composition containing the polymerizable compound at -20°C for 240 hours, the presence or absence of precipitation of the polymerizable compound was observed, which was used as an indicator of low-temperature storage stability. The case where there was no precipitation and did not cause display defects such as bright spots was marked as ◯, and the case where there was precipitation was marked as ×.

Polymerization reaction rate: Under the fixed irradiation conditions of ultraviolet wavelength main band=365nm, illuminance value of 2mW/cm ² , and total irradiation energy of 3J, 6J, and 9J, respectively, the liquid crystal compositions of Comparative Example 1 and Example were irradiated, Then obtain the concentration of polymerizable monomers before and after irradiation by measuring high-performance liquid chromatography, and calculate the ratio (concentration of polymerizable monomers after irradiation (%)/concentration of polymerizable monomers before irradiation (%)), according to the formula: reaction polymerization Conversion rate=1-(concentration of polymerizable monomer after irradiation/concentration of polymerizable monomer before irradiation) to calculate the polymerization reaction rate.

VHR test: test the voltage retention rate (%) before and after ultraviolet light irradiation, the test condition is 60±2°C, the voltage is ±5V, the pulse width is 1ms, and the voltage retention time is 16.7ms. The test equipment is VHR-AMP01 liquid crystal VHR tester. For the deterioration of VHR, ultraviolet light with a wavelength of 365nm was used for light irradiation with an irradiation intensity of 2.5Mw/cm ² and an irradiation time of 34 minutes.

The preparation method of each negative dielectric anisotropic liquid crystal composition in the examples is as follows: each liquid crystal monomer is weighed according to a certain ratio and put into a stainless steel beaker, and the stainless steel beaker containing each liquid crystal monomer is placed in a magnetic stirring Heat and melt on the instrument. After most of the liquid crystal monomers in the stainless steel beaker are melted, add a magnetic rotor to the stainless steel beaker, stir the mixture evenly, and obtain the liquid crystal composition after cooling to room temperature.

The structures of liquid crystal monomers used in the examples are represented by the following codes, and the code representation methods of liquid crystal ring structures, terminal groups, and linking groups are shown in Table (1) and Table (2) below.

Example:

According to the proportions shown in the following Tables 1-10, the liquid crystal compositions of Examples 1-8 and Comparative Examples 1-2 were prepared.

The liquid crystal compositions of the above-mentioned examples and comparative examples were filled between the two substrates of the liquid crystal display for performance testing, and the test results obtained are shown in the table below. It should be noted that Comparative Example 2 does not contain a polymerizable monomer, therefore, no polymerization rate test was performed.

As shown in the above-mentioned Table 11, compared with the liquid crystal composition of Examples 1 to 8 and the liquid crystal composition of Comparative Example 1, the composition containing the polymerizable monomer compound in Examples 1 to 8 was irradiated with ultraviolet rays (UV). After the energy is 3J~9J, the polymerization reaction rate is faster than that of Comparative Example 1, which can shorten the process time for the stable alignment of existing mass-produced polymers.

Furthermore, the amount of the polymerizable compound remaining in the liquid crystal display devices obtained in Examples 1 to 8 was confirmed, and the remaining amount was sufficiently small.

Moreover, compared with the comparative example 1, the liquid crystal composition of Examples 1-8 showed the more excellent low-temperature storage property.

From the above, it was confirmed that when the liquid crystal composition of the present invention is used in PS-VA liquid crystal display devices, PS-VA display devices, etc., it can obtain good low-temperature storage stability and a relatively fast polymerization rate.

Further, the VHR of the compositions of Examples 1-8 after ultraviolet (UV) irradiation is higher than that of the composition of Comparative Example 1 containing the polymerizable monomer compound used in the prior art, which also shows that the compositions of Examples 1-8 The liquid crystal composition of 8 has properties such as a high voltage retention rate, has high reliability, and is not prone to display defects caused by changes in the pretilt angle.

Although the present invention does not exhaust all the liquid crystal mixtures claimed for protection, those skilled in the art can foresee that, on the basis of the above-mentioned disclosed embodiments, other liquid crystal materials of the same type can be obtained in a similar way only in combination with their own professional attempts. No creative labor is required. Due to limited space, only representative implementations are listed here.

Claims (11)

A liquid crystal composition with negative dielectric anisotropy, comprising: at least one compound represented by formula I; at least one compound represented by formula II; and at least one compound represented by formula III;

In formula I, P ₁ and P ₂ each independently represent an acrylate group, a methacrylate group, an ethacrylate group, a propyl acrylate group, a butyl acrylate group, an amyl acrylate group, a fluoroacrylic acid group ester group, fluoromethacrylate group, fluoroethylacrylate group, fluoropropylacrylate group, fluorobutylacrylate group or fluoropentylacrylate group; Z ₁ and Z ₂ are independent means a single bond, a straight-chain alkylene group with 1 to 8 carbon atoms, a straight-chain alkyleneoxy group with 1 to 8 carbon atoms, a straight-chain alkenylene group with 2 to 8 carbon atoms, or a carbon Straight-chain alkenyleneoxy groups with 2~8 atoms, one or two non-adjacent -CH ₂ - are optionally substituted by -O-, any H is optionally substituted by F atom; Y ₁ , Y ₂ , Y ₃ , Y ₄ , Y ₅ , Y ₆ , Y ₇ , Y ₈ , Y ₉ , and Y ₁₀ each independently represent -H, -F, -CH ₃ , -CH ₂ F, -CHF ₂ , -CF ₃ , -C ₂ H ₅ , -OCH ₃ , -OCH ₂ F, -OCHF ₂ , -OCF ₃ or -OC ₂ H ₅ ; n represents 0, 1 or 2; in formula II, R ₃ and R ₄ are each independently Represents an alkyl group with 1 to 5 carbon atoms, an alkoxy group with 1 to 5 carbon atoms, an alkenyl group with 2 to 5 carbon atoms, or an alkenyloxy group with 2 to 5 carbon atoms; ring C , Ring D are each independently selected from the group consisting of the following groups: 1,4-cyclohexylene, cyclohexene-1,4-diyl, 1,4-phenylene, 2-fluoro-1, 4-phenylene, 2,3-difluoro-1,4-phenylene, oxane-2,5-diyl, 1,3-dioxane-2,5-diyl Base, 1-methylcyclohexane-1,4-diyl, 2-methylcyclohexane-1,4-diyl, 2-methylbenzene-1,4-diyl; p means 0, 1 , 2 or 3; in formula III, R ₅ and R ₆ each independently represent an alkyl group with 1 to 5 carbon atoms, an alkoxy group with 1 to 5 carbon atoms, or an alkene group with 2 to 5 carbon atoms group, or an alkenyloxy group with 2 to 5 carbon atoms; Z ₃ represents a single bond or -CH ₂ O-; q, r each independently represent 0, 1 or 2; ring E, ring F are each independently selected from The group consisting of the following groups: 1,4-cyclohexylene, cyclohexene-1,4-diyl, 1,4-phenylene, 2-fluoro-1,4-phenylene, 2, 3-difluoro-1,4-phenylene, oxane-2,5-diyl, 1,3-dioxane-2,5-diyl, 1-methylcyclohexane Alkane-1,4-diyl, 2-methylcyclohexane-1,4-diyl, 2-methylbenzene-1,4-diyl, relative to 100 parts by mass of the negative dielectric anisotropy The liquid crystal composition comprises 0.001-1 parts by mass of the compound represented by the formula I, 10-60 parts by mass of the compound represented by the formula II, and 10-70 parts by mass of the compound represented by the formula III. The negative dielectric anisotropy liquid crystal composition as claimed in Claim 1, wherein the compound represented by the formula I is selected from the group consisting of the compounds represented by the following formulas I-1 to I-57, wherein P ₁ , The definitions of P ₂ , Z ₁ , and Z ₂ are the same as those in claim 1,

The negative dielectric anisotropy liquid crystal composition as claimed in claim 1, wherein the compound represented by the formula I is selected from the group consisting of the compounds represented by the following formulas IA-1 to IA-258;

The negative dielectric anisotropy liquid crystal composition according to Claim 1, wherein the compound represented by the formula II is selected from the group consisting of the compounds represented by the following formulas II-1 to II-11:

R ₃ and R ₄ each independently represent an alkyl group with 1 to 5 carbon atoms, an alkoxy group with 1 to 5 carbon atoms, an alkenyl group with 2 to 5 carbon atoms, or an alkenyl group with 2 to 5 carbon atoms. 5 alkenyloxy; (F) represents F or H. The negative dielectric anisotropy liquid crystal composition according to Claim 1, wherein the compound represented by the formula III is selected from the group consisting of the compounds represented by the following formulas III-1 to III-17:

R ₅ and R ₆ each independently represent an alkyl group with 1 to 5 carbon atoms, an alkoxy group with 1 to 5 carbon atoms, an alkenyl group with 2 to 5 carbon atoms, or an alkenyl group with 2 to 5 carbon atoms. 5 alkenyloxy. The negative dielectric anisotropy liquid crystal composition as claimed in Claim 1, further comprising one or more compounds represented by the following formulas IV-1~IV-50:

Among them, R ₁ ' represents H or an alkyl group with 1 to 8 carbon atoms or an alkenyl group with 2 to 8 carbon atoms, and optionally 4 or less Hs are replaced by F; R ₂ ' represents H or carbon atoms An alkyl group of 1 to 8 or an alkenyl group with a carbon number of 2 to 8, wherein one or two non-adjacent -CH ₂ -s are optionally substituted by -O-, and optionally 4 or less Hs are replaced by F replace. The negative dielectric anisotropy liquid crystal composition as described in Claim 1, which also includes one or more compounds represented by the following formulas V-1~V-78:

The negative dielectric anisotropy liquid crystal composition according to claim 6, wherein, relative to 100 parts by mass of the negative dielectric anisotropy liquid crystal composition, the compound represented by formula I is 0.001 to 0.3 parts by mass, The compound represented by the formula II is 20-60 parts by mass, the compound represented by the formula III is 20-60 parts by mass, and the compound represented by the formula IV is 1-20 parts by mass. The negative dielectric anisotropic liquid crystal composition according to claim 7, wherein, relative to 100 parts by mass of the negative dielectric anisotropic liquid crystal composition, the compound represented by the formula I is 0.001 to 0.3 parts by mass, The compound shown in the formula II is 20-60 parts by mass, the compound shown in the formula III is 20-60 parts by mass, the compound shown in the formula IV is 1-20 parts by mass, and the compound shown in the formula V is 20-60 parts by mass. The compound is 1 to 10 parts by mass. An optical anisotropy composed of a polymer of the liquid crystal composition with negative dielectric anisotropy according to any one of claims 1 to 9. A liquid crystal display device, which is obtained by polymerizing the polymerizable compound in the negative dielectric anisotropy liquid crystal composition using the negative dielectric anisotropy liquid crystal composition described in any one of claims 1 to 9 A liquid crystal display device that imparts alignment properties to liquid crystals.