CN113372924B

CN113372924B - Polymerizable compound, liquid crystal composition thereof and liquid crystal display device

Info

Publication number: CN113372924B
Application number: CN202010159038.9A
Authority: CN
Inventors: 徐海彬; 杨亚非; 丁文全; 徐爽
Original assignee: Jiangsu Hecheng Display Technology Co Ltd
Current assignee: Jiangsu Hecheng Display Technology Co Ltd
Priority date: 2020-03-09
Filing date: 2020-03-09
Publication date: 2023-05-23
Anticipated expiration: 2040-03-09
Also published as: TW202134410A; TWI771940B; CN113372924A

Abstract

Disclosed are a polymerizable compound of the general formula I, a liquid crystal composition comprising the polymerizable compound of the general formula I, a PSA type liquid crystal display device comprising the polymerizable compound of the general formula I, and a PSA type liquid crystal display device comprising the liquid crystal composition. Compared with the prior art, the liquid crystal composition containing the polymerizable compound of the general formula I has the advantages of low roughness (namely, high uniformity) of the polymerized polymer, small change (namely, high stability) caused by ultraviolet irradiation and long-time electrification of the pre-tilt angle and good low-temperature stability, can meet the requirement of a large-size PSA type liquid crystal display device on display uniformity, can effectively avoid the occurrence of poor display phenomena such as broken bright spots, is not easy to generate the problem of uneven regular display caused by the influence of external environment, and has good application value.

Description

Polymerizable compound, liquid crystal composition thereof and liquid crystal display device

Technical Field

The invention relates to the field of liquid crystal display, in particular to a polymerizable compound, a liquid crystal composition thereof and a liquid crystal display device.

Background

Liquid crystal displays (Liquid Crystal Display, LCD) have been rapidly developed due to their small size, light weight, low power consumption and excellent display quality, and have been widely used in particular in portable electronic information products. Depending on the type of display mode, the liquid crystal display device may be classified into PC (phase change), TN (twisted nematic), STN (super twisted nematic ), ECB (electrically controlled birefringence, electrically controlled birefringence), OCB (optically compensated bend ), IPS (in-plane switching), FFS (fringe field switching ), VA (vertical alignment, homeotropic alignment), and PSA (polymer stable alignment), among others.

The PSA mode is to add a small amount (e.g., 0.3wt%, more typically < 1 wt%) of one or more polymerizable compounds to the liquid crystal composition and to polymerize or crosslink the liquid crystal molecules in situ (typically by UV photopolymerization) in a state where the liquid crystal molecules have an initial orientation with or without applying a voltage between electrodes after filling the liquid crystal cell. The polymerization is carried out at a temperature at which the liquid crystal composition exhibits a liquid crystal phase (usually at room temperature). The addition of a polymerizable liquid crystal compound to a liquid crystal composition has proved to be particularly suitable because the polymer structure formed within the cell can well control the tilt angle of the liquid crystal molecules, and the PSA-type liquid crystal display element also has the effects of high-speed responsiveness and high contrast.

Accordingly, PSA-type liquid crystal display elements have been continuously developed, and PSA principles have also been used in various conventional liquid crystal display devices, such as known PSA-VA, PSA-OCB, PSA-IPS, PSA-FFS, and PSA-TN type displays. In a PSA-type liquid crystal display device, a liquid crystal composition containing a polymerizable compound is located between two substrates, each of which is provided with an electrode structure, or two electrode structures are disposed on only one of the substrates. In addition, one or both of the substrates may contain an alignment layer disposed on the substrate or electrode structure (if present) so as to be in contact with the liquid crystal composition to induce initial alignment of the liquid crystal composition. As with conventional liquid crystal display devices, PSA-type liquid crystal display devices can operate as either active matrix or passive matrix displays. In the case of active matrix displays, the individual pixels are usually addressed by integrated non-linear active elements, such as transistors, whereas in the case of passive matrix displays the individual pixels are usually addressed according to multiplexing methods known in the art.

After filling the liquid crystal composition into the display device, the polymerizable compound contained in the liquid crystal composition is typically polymerized or crosslinked in situ by UV photopolymerization, which is accomplished by exposing the liquid crystal composition to UV radiation (preferably while applying a voltage to the electrode structure). As a result of UV exposure, the polymerized or crosslinked polymerizable compounds phase separate from the liquid crystal composition and form a polymer layer on the substrate surface where they cause the liquid crystal molecules to form a pretilt angle with respect to the substrate. In the case of liquid crystal display devices of the PSA-VA, PSA-OCB, PSA-FFS and PSA-TN types, polymerization of the polymerizable compound is preferably performed with application of a voltage; in the case of a PSA-IPS type liquid crystal display device, voltage may be applied or not applied, and it is preferable that voltage is not applied.

In general, UV photopolymerization in a production method of a PSA-type liquid crystal display device is performed in two steps. In a first step (hereinafter also referred to as "UV1 step"), the liquid crystal composition is exposed to UV radiation emitted by a radiation source (hereinafter also referred to as "light source") while a voltage is applied to the electrode structure to create a pretilt angle. In a second step (hereinafter also referred to as "UV2 step"), the liquid crystal composition is exposed to UV irradiation without applying a voltage to ensure thorough polymerization of any residual polymerizable compound not polymerized in the UV1 step. As described above, thorough polymerization is important because residual unreacted polymerizable compounds may lead to undesirable effects (such as reduced reliability, reduced tilt angle stability, or image sticking in the display). Furthermore, it is important to ensure that the polymerization in the UV2 step is completed within an acceptable time, so that the takt time is significantly shorter than 2 hours. Furthermore, the UV intensity in the UV2 step should be reduced compared to the UV1 step to avoid or reduce negative effects (such as reduced reliability or image sticking).

However, PSA-type liquid crystal display elements also have some display defects (such as image retention). Studies have shown that such problems are mostly caused by the presence of impurities and by variations in the orientation of the liquid crystal molecules (variations in the pretilt angle), which are controlled by the polymer network formed after polymerization of the polymerizable compounds. If the structural rigidity of the polymerizable compound constituting the polymer network is insufficient, there is a possibility that the structure of the polymer network changes when the PSA-type liquid crystal display element continuously displays the same pattern for a long period of time, which in turn causes a change in the pretilt angle of the liquid crystal molecules. Thus, it is often desirable to select polymerizable compounds having a rigid structure.

The prior art uses widely polymerizable compounds of the following formulae (a), b):

wherein P is ₁ And P ₂ Each independently represents a polymerizable group, which is typically an acrylate group or a methacrylate group.

The more preferred polymerizable compound should be to produce a smaller pretilt angle than the existing RM (reactive monomer) at the same exposure time during polymerization or to produce the same pretilt angle as the existing RM at a shorter UV exposure time, so that the production time of the display device can be saved, thereby speeding up the production efficiency of the display device and reducing the cost.

However, with the development of technology, the liquid crystal display industry (especially the TV industry) has more stringent requirements on the display quality of LCDs. The size of TV is generally increased, and the LCD production line is also increased, which results in a significant increase in the difficulty of the manufacturing process of the large-sized LCD panel. Therefore, how to ensure the display quality is a problem to be solved. In addition to continuously optimizing the panel manufacturing process, the continuous development of liquid crystal materials is one of the solutions. In particular, for PSA-type liquid crystal display devices, improvements in the performance of various aspects of polymerizable compounds are a hot spot of research.

At present, common problems in the production of PSA-type liquid crystal display devices are: residual or removal of polymerizable compounds, stability of pre-tilt angle. In the PSA type liquid crystal display device, after the polymerizable compound is polymerized by applying UV1 light and UV2 light to generate a pretilt angle, a small amount of the polymerizable compound that is not always reacted may be polymerized in an uncontrollable manner after the display device is manufactured, thereby affecting the quality of the display. For example, residual polymerizable compounds may be subjected to UV light or backlighting from the environment to initiate polymerization, wherein in the region of the display device being turned on, the pretilt angle may change and the transmittance may change after a number of addressing cycles, while the pretilt angle and the transmittance remain unchanged in the non-turned-on regions, thereby exhibiting an "image sticking" effect. Accordingly, it is desirable that the polymerizable compound be polymerized as completely as possible during the production of the PSA-type liquid crystal display device, and that the controlled reaction of the residual polymerizable compound be desired, wherein the faster the polymerization speed, the more advantageous it is to achieve the desire. Furthermore, it is desirable that the change in the pre-tilt angle is small after a plurality of address periods.

Another problem observed in the operation of the PSA-type liquid crystal display device is display unevenness (mura). In the manufacturing process of PSA-type liquid crystal display devices, the action of external conditions such as light, heat, stress, etc. is required, and UV exposure is particularly indispensable. As can be seen from the above, the UV photopolymerization requires a UV1 step and a UV2 step, and the UV2 step affects the pre-tilt angle that is formed, wherein the larger the pre-tilt angle is, the more susceptible the PSA-type liquid crystal display device is to the non-uniformity of the UV process (non-uniformity of external conditions such as light, heat, stress, etc.), and the corresponding display non-uniformity is generated. It is therefore desirable to obtain polymerizable compounds that have less variation in pre-tilt angle after two UV light shots, thereby more facilitating a wider process margin and better display uniformity.

Another common problem in PSA-type liquid crystal display devices is the tendency to appear as "bright spots" due to the excessive fraction of polymer particles formed by the polymerizable compound during polymerization. The polymer particles are not uniform in size, and thus the polymer is unevenly distributed, which results in a problem of uneven display. It is therefore desirable to obtain polymerizable compounds capable of forming smaller and uniformly distributed polymer particles, thereby improving the problems of "broken bright spots" and display irregularities.

In addition, the polymerizable compounds of the prior art generally have a high melting point and show only limited solubility in many of the liquid crystal compositions commonly used in the prior art, so that they often precipitate from the liquid crystal composition. Furthermore, the polymerizable compound has a possibility of self-polymerization, so that its solubility in the liquid crystal composition is further deteriorated. Therefore, it is generally necessary to introduce a liquid crystal composition in which a polymerizable compound is dissolved at a low temperature in order to reduce the risk of self-polymerization of the polymerizable compound, which is more demanding for the solubility of the polymerizable compound in the liquid crystal composition (particularly, the solubility at a low temperature).

Accordingly, it is desirable to develop a polymerizable compound that can simultaneously satisfy the above-mentioned requirements or at least one of the requirements, and a liquid crystal composition comprising the polymerizable compound.

Disclosure of Invention

The invention aims to: in view of the drawbacks of the prior art, an object of the present invention is to provide a polymerizable compound having reduced post-polymerization polymer roughness, a small change in pre-tilt angle due to ultraviolet irradiation and long-time energization (i.e., high stability), and good low-temperature stability. Another object of the present invention is to provide a liquid crystal composition comprising the polymerizable compound. It is still another object of the present invention to provide a PSA-type liquid crystal display device comprising the liquid crystal compound. Still another object of the present invention is to provide a PSA-type liquid crystal display device comprising the liquid crystal composition.

The technical scheme of the invention is as follows:

in order to achieve the above object, the present invention provides a polymerizable compound of the general formula I:

wherein, the liquid crystal display device comprises a liquid crystal display device,

r and X ₁ ～X ₁₂ Each independently represents-H, halogen, -CN, -Sp ₂ -P ₂ Or a linear, branched or cyclic alkyl group having 1 to 12 carbon atoms, wherein one or not adjacent more than 2-CH groups in the linear, branched or cyclic alkyl group having 1 to 12 carbon atoms ₂ Can be independently and individually substituted by-CH=CH-, -C≡C-, -O-, -CO-O-or-O-CO-substitution, one or more-H mayAre each independently substituted by-F or-Cl, wherein X ₁ ～X ₁₂ At least one of which represents-Cl;

P ₁ and P ₂ Each independently represents a polymerizable group;

Sp ₁ and Sp ₂ Each independently represents a spacer group or a single bond;

Z ₁ and Z ₂ Each independently represents-O-, -S-, -CO-; -CO-O-, -O-CO-O-, -CH ₂ O-、-OCH ₂ -、-CH ₂ S-、-SCH ₂ -、-CF ₂ O-、-OCF ₂ -、-CF ₂ S-、-SCF ₂ -、-(CH ₂ ) _n -、-CF ₂ CH ₂ -、-CH ₂ CF ₂ -、-(CF ₂ ) _n -、-CH＝CH-、-CF＝CF-、-CH＝CF-、-CF＝CH-、-C≡C-、-CH＝CH-CO-O-、-O-CO-CH＝CH-、-CH ₂ CH ₂ -CO-O-、-O-CO-CH ₂ CH ₂ -、-CR ¹ R ² -or a single bond;

R ¹ and R is ² Each independently represents-H, or a linear or branched alkyl group having 1 to 12 carbon atoms;

a represents an integer of 0 to 2, wherein when a represents 2, Z ₂ May be the same or different and may be used,

may be the same or different; and is also provided with

n represents an integer of 1 to 4.

In some embodiments of the invention, preferably, R represents-Sp ₂ -P ₂ 。

In some embodiments of the invention, preferably, a represents 0 or 1.

In some embodiments of the present invention, preferably, the polymerizable compound of formula I is selected from the group consisting of:

/>

/>

/>

X ₁ ～X ₁₂ each independently represents-F, -Cl, -Sp ₂ -P ₂ Or a linear, branched or cyclic alkyl or alkoxy group having 1 to 5 carbon atoms.

In some embodiments of the invention, preferably, Z ₁ And Z ₂ At least one of which represents a single bond; further preferably, Z ₁ And Z ₂ All represent a single bond.

The polymerizable groups to which the invention relates are groups suitable for polymerization reactions (e.g. free radical or ionic bonding polymerization, polyaddition or polycondensation), or groups suitable for addition or condensation on the polymer backbone. For the groups used for chain polymerization, particular preference is given to groups comprising-C=C-or-C.ident.C-; of the groups suitable for ring-opening polymerization, oxetane or epoxy groups, for example, are particularly preferred.

In some embodiments of the invention, preferably, the polymerizable group represents

or-SH; particularly preferably, the polymerizable group represents

As used herein, the term "spacer group" is known to those skilled in the art and is described in the literature, e.g., pure appl. Chem.2001,73 (5), 888 and C.Tschierske, G.Pelzl, S.Diele, angew.Chem.2004,116,6340-6368. As used herein, the term "spacer group" means a flexible group that connects a mesogenic group and a polymerizable group in a polymerizable compound. Typical spacer groups are for example- (CH) ₂ ) _p1 -、-(CH ₂ CH ₂ O) _q1 -CH ₂ CH ₂ -、-(CH ₂ CH ₂ S) _q1 -CH ₂ CH ₂ -、-(CH ₂ CH ₂ NH) _q1 -CH ₂ CH ₂ -、-CR ⁰ R ⁰⁰ -(CH ₂ ) _p1 -or- (SiR) ⁰ R ⁰⁰ -O) _p1 -, wherein p1 represents an integer of 1 to 12, q1 represents an integer of 1 to 3, R ⁰ And R is ⁰⁰ Each independently represents-H, or a linear, linear or cyclic alkyl group containing 1 to 12 carbon atoms. A particularly preferred spacer group is- (CH) ₂ ) _p1 -、-(CH ₂ ) _p1 -O-、-(CH ₂ ) _p1 -O-CO-、-(CH ₂ ) _p1 -CO-O-、-(CH ₂ ) _p1 -O-CO-O-or-CR ⁰ R ⁰⁰ -(CH ₂ ) _p1 -。

The invention also provides a liquid crystal composition comprising the polymerizable compound of the general formula I.

In some embodiments of the invention, the liquid crystal composition contains one, two or three polymerizable compounds of formula I described above.

In some embodiments of the present invention, the polymerizable compound of formula I comprises 0.001 to 5% by weight of the total liquid crystal composition; preferably, the polymerizable compound of formula I comprises 0.01 to 2% by weight of the total liquid crystal composition; further preferably, the polymerizable compound of formula I comprises 0.25 to 0.4% by weight of the total liquid crystal composition.

In some embodiments of the invention, the liquid crystal composition further comprises one or more compounds of formula M

M，

R _M1 and R is _M2 Each independently represents a linear or branched alkyl group having 1 to 12 carbon atoms,

1 or non-adjacent more than 2-CH in the straight-chain or branched alkyl group containing 1-12 carbon atoms ₂ -may each be independently replaced by-ch=ch-, -c≡c-, -O-, -CO-O-, or-O-CO-;

Ring(s)

Ring->

And (C) a ring->

Each independently represents->

Wherein->

One or more of-CH ₂ -can be replaced by-O->

At most one-H of (c) may be substituted by halogen;

Z _M1 and Z _M2 Each independently represents a single bond, -CO-O-, -O-CO-, -CH ₂ O-、-OCH ₂ -、-CH＝CH-、-C≡C-、-CH ₂ CH ₂ -、-(CH ₂ ) ₄ -、-CF ₂ O-、-OCF ₂ -or-CF ₂ CF ₂ -; and is also provided with

n _M1 Represents 0, 1, 2 or 3, wherein when n _M1 When=2 or 3, the ring

Z, which may be the same or different _M2 May be the same or different.

In some embodiments of the invention, in the compound of formula M, R _M1 And R is _M2 Preferably, each independently is a linear alkyl group having 1 to 10 carbon atoms, a linear alkoxy group having 1 to 9 carbon atoms, or a linear alkenyl group having 2 to 10 carbon atoms; further preferably, each independently is a linear alkyl group having 1 to 8 carbon atoms, a linear alkoxy group having 1 to 7 carbon atoms, or a linear alkenyl group having 2 to 8 carbon atoms; still more preferably, each independently is a linear alkyl group having 1 to 5 carbon atoms, a linear alkoxy group having 1 to 4 carbon atoms, or a linear alkenyl group having 2 to 5 carbon atoms.

In some embodiments of the invention, R _M1 And R is _M2 Preferably each independently is a linear alkenyl group having 2 to 8 carbon atoms, and more preferably each independently is a linear alkenyl group having 2 to 5 carbon atoms.

In some embodiments of the invention, preferably, R _M1 And R is _M2 Either one of them is a linear alkenyl group having 2 to 5 carbon atoms, and the other is a linear alkyl group having 1 to 5 carbon atoms.

In some embodiments of the invention, R _M1 And R is _M2 Preferably each independently is a straight chain having 1 to 8 carbon atomsAn alkyl group or a linear alkoxy group having 1 to 7 carbon atoms; further preferably, each independently is a linear alkyl group having 1 to 5 carbon atoms or a linear alkoxy group having 1 to 4 carbon atoms.

In some embodiments of the invention, preferably, R _M1 And R is _M2 Either one of them is a linear alkyl group having 1 to 5 carbon atoms, and the other is a linear alkyl group having 1 to 5 carbon atoms or a linear alkoxy group having 1 to 4 carbon atoms; further preferably, R _M1 And R is _M2 Each of them is independently a linear alkyl group having 1 to 5 carbon atoms.

The alkenyl group in the present invention is preferably selected from the group represented by any one of the formulas (V1) to (V9), and particularly preferably is formula (V1), formula (V2), formula (V8) or (V9). The groups represented by the formulas (V1) to (V9) are as follows:

/>

wherein represents a carbon atom in the bonded ring structure.

The alkenyloxy group in the present invention is preferably selected from the group represented by any one of the formulas (OV 1) to (OV 9), and particularly preferably is formula (OV 1), formula (OV 2), formula (OV 8) or (OV 9). The groups represented by the formulas (OV 1) to (OV 9) are as follows:

wherein represents a carbon atom in the bonded ring structure.

In some embodiments of the invention, the compound of formula M is selected from the group consisting of:

/>

/>

in some embodiments of the invention, the compounds of formula M are preferably selected from the group consisting of compounds of formula M1, formula M2, formula M4, formula M9, formula M11, formula M20 and formula M21.

The preferred lower limit of the content of the compound of the formula M is 1%,5%,10%,20%,25%,30%,40% or 50% relative to the total weight of the liquid-crystalline composition of the invention; the upper limit of the preferred content of the compound of the formula M is 70%,65%,60%,55%,45%,35% or 25% relative to the total weight of the liquid crystal composition of the present invention.

In order to adjust the properties of the liquid crystal composition in terms of clearing point, viscosity, low-temperature storage stability and the like so that the obtained liquid crystal display device has better application value in terms of transmittance and color expression, the component constitution of the liquid crystal composition needs to be adjusted. Specifically, the compound of formula M has a ring relative to the total weight of the liquid crystal composition of the invention

Representation->

The content of the compound of (a) is 10 to 65%, preferably 20 to 60%.

Regarding the content of the compound of the general formula M, when it is necessary to keep the viscosity of the liquid crystal composition of the present invention low and the response time short, it is preferable that the lower limit value and the upper limit value thereof be high; further, when it is necessary to keep the clearing point of the liquid crystal composition of the present invention high and the temperature stability good, it is preferable that the lower limit value is high and the upper limit value is high; when the absolute value of the dielectric anisotropy becomes large in order to keep the driving voltage low, the lower limit value and the upper limit value are preferably made low.

In the case where reliability is important, R is preferable _M1 And R is _M2 Each independently is alkyl; in the case where importance is attached to reducing the volatility of the compound, R is preferably _M1 And R is _M2 Each independently is an alkoxy group; when importance is attached to the reduction of viscosity, R is preferable _M1 And R is _M2 At least one of which is alkenyl.

In some embodiments of the invention, the liquid crystal composition contains one or more R _M1 And/or R _M2 A compound of formula M1 which is n-propyl.

In some embodiments of the invention, the liquid crystal composition further comprises one or more compounds of formula N

R _N1 and R is _N2 Each independently represents a linear or branched alkyl group having 1 to 12 carbon atoms,

1 or non-adjacent more than 2-CH in the straight-chain or branched alkyl group containing 1-12 carbon atoms ₂ -may each independently be replaced by-ch=ch-, -c≡c-, -O-, -CO-O-, or-O-CO-, and one or more-H present in these groups may each independently be substituted by-F or-Cl; />

Ring(s)

And (C) a ring->

Each independently represents->

Wherein the method comprises the steps of

One or more of-CH ₂ Can be replaced by-O-and one or at most two single bonds in the ring can be replaced by double bonds, wherein +.>

In which-H may be substituted by-F or-Cl, and-ch=may be replaced by-n=in one or more rings;

Z _N1 and Z _N2 Each independently represents a single bond, -CO-O-, -O-CO-, -CH ₂ O-、-OCH ₂ -、-CH＝CH-、-C≡C-、-CH ₂ CH ₂ -、-(CH ₂ ) ₄ -、-CF ₂ O-、-OCF ₂ -or-CF ₂ CF ₂ -；

L _N1 And L _N2 Each independently represents-H or methyl; and is also provided with

n _N1 Represents 0, 1, 2 or 3, n _N2 Represents 0 or 1, and 0.ltoreq.n _N1 +n _N2 Not more than 3, wherein when n _N1 When=2 or 3, the ring

Z, which may be the same or different _N1 May be the same or different.

In some embodiments of the invention, in the compound of formula N, R _N1 And R is _N2 Preferably each independently is an alkyl or alkoxy group having 1 to 8 carbon atoms, or an alkenyl or alkenyloxy group having 2 to 8 carbon atoms, more preferably each independently is an alkyl or alkoxy group having 1 to 5 carbon atoms, or an alkenyl or alkenyloxy group having 2 to 5 carbon atoms;

R _N1 More preferably an alkyl group having 1 to 5 carbon atoms, or an alkenyl group having 2 to 5 carbon atoms, still more preferably an alkyl group having 2 to 5 carbon atoms, or an alkenyl group having 2 to 3 carbon atoms;

R _N2 further preferred are alkoxy groups having 1 to 4 carbon atomsA base;

ring(s)

And (C) a ring->

Preferably +.>

In some embodiments of the invention, the compound of formula N is selected from the group consisting of:

/>

/>

in some embodiments of the invention, the compound of formula N is preferably selected from the group consisting of compounds of formula N2, formula N3, formula N5, formula N8, formula N12, formula N14, formula N16, and formula N17.

The preferred lower limit of the content of the compound of the formula N is 0.1%,0.5%,1%,3%,5%,10%,13%,15%,18%,20%,23%,25%,28%,30%,33%,35%,38% or 40% relative to the total weight of the liquid crystal composition of the present invention; the preferred upper limit of the content of the compound of the formula N is 75%,72%,70%,68%,65%,63%,60%,55%,50%,40%,38%,35%,33%,30%,28%,25%,23%,20%,18%,15% or 10% relative to the total weight of the liquid crystal composition of the present invention.

Regarding the preferable content of the compound of the general formula N, when it is necessary to keep the response time of the liquid crystal display device of the present invention short, it is preferable that the lower limit value and the upper limit value thereof are low; further, when it is necessary to keep the operating temperature range of the liquid crystal display device of the present invention wider, it is preferable that the lower limit value and the upper limit value thereof be lower; in addition, when the absolute value of the dielectric anisotropy is increased in order to keep the driving voltage of the liquid crystal composition low, it is preferable that the lower limit value and the upper limit value are increased.

In some embodiments of the present invention, one or more other additives known to those skilled in the art and described in the literature may be added to the liquid crystal composition.

The following are mentioned, for example, stabilizers which can be added to the liquid crystal composition according to the invention:

/>

/>

/>

wherein n represents a positive integer of 1 to 12.

Preferably, the stabilizer is selected from the stabilizers shown below.

In some embodiments of the invention, preferably, the stabilizer comprises 0-5% of the total weight of the liquid crystal composition; more preferably, the stabilizer comprises 0-1% of the total weight of the liquid crystal composition; particularly preferably, the stabilizer comprises 0.001 to 0.1% by weight of the total liquid crystal composition.

The liquid crystal composition containing a polymerizable compound of the present invention can be polymerized even in the absence of a polymerization initiator; however, a polymerization initiator may be contained in the composition for promoting polymerization. Examples of the polymerization initiator include benzoin ethers, benzophenones, acetophenones, benzil ketals, and acylphosphine oxides.

The liquid crystal composition of the present invention can be used to impart a pretilt angle to liquid crystal by polymerization of a polymerizable compound in the liquid crystal composition and to control the amount of transmitted light in a liquid crystal display device by utilizing birefringence in the liquid crystal composition.

As a polymerization method of a polymerizable compound, a method of polymerizing by irradiation with active energy rays such as ultraviolet rays or electron beams is preferable because it is desired to rapidly perform polymerization. When ultraviolet rays are used, polarized light sources or unpolarized light sources may be used. In addition, when polymerization is performed in a state in which the liquid crystal composition is sandwiched between two substrates, at least the substrate on the irradiation surface side must have appropriate transparency with respect to the active energy rays. In addition, a mask may be used at the time of light irradiation. After polymerizing only a specific portion, the orientation state of the unpolymerized portion is changed by changing conditions such as an electric field, a magnetic field, or a temperature, and further, an active energy ray is irradiated to polymerize. In particular, in the case of performing ultraviolet exposure, it is preferable to perform ultraviolet exposure while applying a voltage to the liquid crystal composition.

The temperature at the time of ultraviolet irradiation is preferably a temperature range in which the liquid crystal state of the liquid crystal composition of the present invention is maintained. The polymerization is preferably carried out at a temperature close to room temperature (i.e., 15 to 35 ℃). As the lamp that generates ultraviolet rays, a metal halide lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, or the like can be used. The wavelength of the irradiated ultraviolet light is preferably ultraviolet light outside the absorption wavelength region of the liquid crystal composition, and is preferably used by blocking ultraviolet light if necessary. Irradiated with lightThe intensity of the ultraviolet light is preferably 0.1mW/cm ² ～50mW/cm ² . When the ultraviolet rays are irradiated, the intensity may be changed, and the time for irradiating the ultraviolet rays (preferably, 10s to 600 s) may be appropriately selected according to the intensity of the irradiated ultraviolet rays.

The present invention also provides a liquid crystal display device, preferably a PSA-type liquid crystal display device, more preferably a PS-VA, PS-OCB, PS-IPS, PS-FFS, PS-UB-FFS, PS-positive-VA or PS-TN-type liquid crystal display device, comprising a polymerizable compound of the above general formula I.

The present invention also provides a liquid crystal display device, preferably a PSA-type liquid crystal display device, more preferably a PS-VA, PS-OCB, PS-IPS, PS-FFS, PS-UB-FFS, PS-positive-VA or PS-TN-type liquid crystal display device, comprising the above liquid crystal composition.

As used herein, the terms "tilt" and "tilt angle" will be understood as the tilt alignment of liquid crystal molecules with respect to the cell surface in a liquid crystal display device (preferably, a PSA-type liquid crystal display device). The tilt angle represents the average angle (< 90 °) formed between the longitudinal molecular axis of the liquid crystal molecules (liquid crystal director loss) and the surface of the outer plate of the liquid crystal cell. A low value of the tilt angle (i.e., a large angle deviating from 90 deg.) corresponds to a large tilt.

The beneficial effects are that:

compared with the prior art, the liquid crystal composition containing the polymerizable compound of the general formula I has the advantages of low roughness (namely, high uniformity) of the polymerized polymer, small change (namely, high stability) caused by ultraviolet irradiation and long-time electrification of the pre-tilt angle and good low-temperature stability, can meet the requirement of a large-size PSA type liquid crystal display device on display uniformity, can effectively avoid the occurrence of poor display phenomena such as broken bright spots, is not easy to generate the problem of uneven regular display caused by the influence of external environment, and has good application value.

Detailed Description

The invention will be described below in connection with specific embodiments. The following examples are illustrative of the present invention and are not intended to limit the present invention. Other combinations and various modifications within the spirit of the invention may be made without departing from the spirit or scope of the invention.

In the invention, unless otherwise specified, the proportions are weight ratios, and all temperatures are temperatures of degrees celsius.

For ease of expression, in the following examples, the group structures of the liquid crystal compounds are represented by the codes listed in Table 1:

TABLE 1 group Structure codes for liquid Crystal Compounds

/>

Take as an example a compound of the formula:

the structural formula is expressed by codes listed in table 1, and can be expressed as follows: nCCGF, where n in the code represents the number of C atoms in the left-hand alkyl group, e.g., n is "3", i.e., the alkyl group is-C ₃ H ₇ The method comprises the steps of carrying out a first treatment on the surface of the C in the code represents 1, 4-cyclohexylene, G represents 2-fluoro-1, 4-phenylene and F represents a fluorine substituent.

The shorthand designations for the test items in the following examples are as follows:

cp clearing point (nematic phase-isotropic phase transition temperature, DEG C)

Delta epsilon dielectric anisotropy (1 KHz,25 ℃ C.)

Δn optical anisotropy (illumination wavelength 589nm,25 ℃ C.)

Gamma 1 rotational viscosity (mPa. S)

Ra surface roughness (nm)

Changes in pretilt angle (°) after ΔPTA (UV) UV2 irradiation

Stability of ΔPTA (168 h) Pre-Tilt Angle (Pre-Tilt Angle Change after 168h Power-on)

t _-20℃ Storage time at low temperature of-20 ℃ (Tian)

clearing point Cp: by a melting point tester.

Dielectric anisotropy Δε: delta epsilon=epsilon _‖ -ε _⊥ Wherein ε is _‖ For dielectric constant parallel to the molecular axis ε _⊥ For dielectric constants perpendicular to the molecular axis, test conditions: VA type test box with 25 deg.C, 1KHz and box thickness of 6 μm.

Optical anisotropy Δn: was measured at 25℃using an Abbe refractometer under a light source having a light wavelength of 589 nm.

Rotational viscosity γ1: test using LCM-2 type liquid crystal physical property evaluation system, test conditions: 25 ℃,240V, and 20 μm thick test box.

Surface roughness Ra: after polymerizing a liquid crystal composition containing a polymerizable compound by UV irradiation, liquid crystal molecules were rinsed off, and the polymerized polymer layer was tested for surface roughness using an Atomic Force Microscope (AFM).

Δpta (UV): filling liquid crystal into a VA type fish bone electrode test box with the box thickness of 3.5 mu m by using a crystal rotation method, applying voltage of 16V and 60Hz, and simultaneously irradiating by using ultraviolet light UV1 to polymerize a polymerizable compound to form a pre-tilt angle PTA1; then, the voltage is removed and the liquid crystal composition with the pre-tilt angle PTA1 is continuously irradiated with ultraviolet light UV2 to eliminate the residual polymerizable compound in the state of PTA1, wherein the pre-tilt angle formed by the polymerizable compound is PTA2, delta PTA (UV) =PTA 1-PTA2, and the illumination condition of UV1 is as follows: 313nm, 0.5mW/cm ² The UV2 light conditions were: 365nm, 36mW/cm ² 。

Stability of the pretilt angle: after the test box for Δpta (UV) test is irradiated with UV1 and UV2 to form a pre-tilt angle of 88±0.2°, a short wave of 60Hz, an AC voltage of 20V and a DC voltage of 2V are applied to the test box, and after a fixed time passes in an environment of 40 ℃ and a backlight, the pre-tilt angle of the test box in the time period, Δpta (168 h) =pta (initial) -PTA (168 h later), wherein a smaller Δpta (168 h) indicates a better stability of the pre-tilt angle.

Low temperature storage time t _-20℃ : the glass bottle containing the liquid crystal composition was stored in a low temperature environment of-20℃and observed for the presence or absence of crystal precipitation at a fixed time.

The polymerizable compounds of the general formula I according to the invention can be prepared by conventional organic synthesis methods. Methods for introducing target terminal groups, cyclic groups and linking groups into starting materials are described in the following documents: organic synthesis (Organic Synthesis, john wili parent-child publishing company (John Wiley & Sons inc.), organic reaction (Organic Reactions, john wili parent-child publishing company (John Wiley & Sons inc.), and comprehensive organic synthesis (Comprehensive Organic Synthesis, pegman publishing company (Pergamon Press)), and the like.

Generating the linking group Z in the polymerizable compound of formula I ₁ And Z ₂ The method of (1) can be referred to the following scheme, wherein MSG ¹ And MSG ² Each independently represents a 1-valent organic group having at least one ring, a plurality of MSGs used in the following schemes ¹ (or MSG) ² ) May be the same or different.

(1) Synthesis of Single bond

Arylboronic acid 1 is reacted with compound 2 synthesized by known methods in aqueous sodium carbonate over a catalyst (e.g., tetrakis (triphenylphosphine) palladium (Pd (PPh) ₃ ) ₄ ) In the presence of a single bond to give the single bond compound IA. It is also possible to synthesize the compound 3 by known methods by reacting it with n-butyllithium (n-BuLi) and then with zinc chloride, and then reacting it with a catalyst such as bis (triphenylphosphine) palladium dichloride (PdCl ₂ (PPh ₃ ) ₂ ) With compound 2) in the presence of a catalyst to produce compound IA.

(2) Synthesis of-COO-or-OCO-

Compound 3 was reacted with n-butyllithium and then reacted with carbon dioxide to obtain carboxylic acid 4. Compound 4 was dehydrated with phenol 5 synthesized by a known method in the presence of 1, 3-Dicyclohexylcarbodiimide (DCC) and 4-Dimethylaminopyridine (DMAP) to synthesize compound IB having-COO-. Compounds having-OCO-can also be synthesized by this method.

(3)-CF ₂ O-and-OCF ₂ -synthesis of

Reference m. kuroboshi et al, chem. Rapid et al (chem. Lett.), 1992,827, compound 6 was obtained by treatment of compound IB with a sulfiding agent, such as lawsen's reagent, followed by fluorination of compound 6 with hydrogen fluoride-pyridine (HF-Py) and N-bromosuccinimide (NBS) to synthesize a compound having-CF ₂ Compound IC of O-. Reference may also be made to W.H. Bunnelle et al, journal of organic chemistry (J. Org. Chem), 1990, 55, 768, for the preparation of a compound having-CF by fluorinating compound 6 with (diethylamino) sulfur trifluoride (DAST) ₂ Compound IC of O-. Synthesis of the polypeptide having-OCF by these methods is also possible ₂ -a compound.

(4) -ch=ch-synthesis

Compound 3 is reacted with N-butyllithium and then with a formamide, such as N, N-Dimethylformamide (DMF), to obtain aldehyde 7. Potassium tert-butoxide (t-BuOK) was reacted with phosphonium and aldehyde 7 produced by reacting phosphonium salt 8 synthesized by a known method to give compound ID. The above process yields the cis-isomer due to the reaction conditions. It will be appreciated that the cis-isomer may be converted to the trans-isomer by known methods, as desired.

(5)-CH ₂ CH ₂ -synthesis of

Compound IE can be prepared by subjecting compound ID to hydrogenation reaction with a catalyst such as palladium on carbon (Pd/C).

(6)-CH ₂ O-or-OCH ₂ -synthesis of

Sodium borohydride (NaBH) ₄ ) The compound 7 was reduced to obtain a compound 9. Then, compound 9 is halogenated with hydrobromic acid to obtain compound 10, or the hydroxyl group of compound 9 is protected with p-toluenesulfonic acid (TsOH) to obtain compound 11. Then, compound 10 or compound 11 is reacted with compound 5 in the presence of potassium carbonate to obtain compound IF. Synthesis of the compounds having-OCH by these methods is also possible ₂ -a compound.

Regarding the ring structures such as 1, 4-cyclohexylene, 1, 3-dioxane-2, 5-diyl, 1, 4-phenylene, 2-fluoro-1, 4-phenylene, 2, 3-difluoro-1, 4-phenylene, 2, 5-difluoro-1, 4-phenylene, 2, 6-difluoro-1, 4-phenylene, 2,3,5, 6-tetrafluoro-1, 4-phenylene, starting materials or synthetic methods thereof have been commercially available and are known in the art.

Preferred synthetic methods for representative compounds are set forth below.

Synthesis example 1

Synthesis of Compound I-1-a:

(1) Preparation of Compounds 1-3

To a 500mL three-necked flask were added 35g (169 mmol) of Compound 1-1, 24.42g (177 mmol) of Compound 1-2, 175mL of toluene, 100mL of ethanol, 100m L of water, 29.76g (354 mmol) of sodium bicarbonate and 0.07g (0.1 mmol) of bis-tert-butyl- (4-dimethylaminophenyl) phosphine palladium (II) dichloride. The mixture was subjected to nitrogen substitution 3 times and reacted at a controlled temperature of 60℃to 70℃for 2 hours.

The reaction solution was cooled to room temperature, and left to stand for separation. The aqueous phase was extracted with 2X 100mL toluene and the total organic phases were combined. The combined organic phases were washed sequentially with 3X 80mL of water, dried over anhydrous sodium sulfate, and concentrated to give the crude product. Then, petroleum ether was added to the crude product in an amount of 4 times by volume, slurried at room temperature for 2 hours, and then frozen and devitrified at a temperature of-10 to-20℃for 6 hours, followed by suction filtration to obtain 31.5g of a white solid (GC purity: 99.3%; yield: 84.62%).

MS：127(13％)、128(22％)、155(13％)、157(6％)、220(100％)、221(15％)、222(35％)。

(2) Preparation of Compound I-1-a

To a 500mL three-necked flask was added 200mL of methylene chloride, and 20g (90.6 mmol) of compound 1-3, 19.5g (226 mmol) of compound MAC and 3.32g (27.2 mmol) of 4-dimethylaminopyridine were added under nitrogen protection and stirring. The mixture was cooled to 0-10 ℃ and 56.05g (272 mmol) of dicyclohexylcarbodiimide solution (dissolved in 40mL of dichloromethane) was added dropwise while maintaining a temperature of 0-10 ℃. After the dripping is finished, the reaction is carried out for 3 to 4 hours at the temperature of between 0 and 10 ℃.

After the reaction was completed, filtration was performed, and the cake was washed with 50ml×3 dichloromethane. The reaction solution and the washing solution were combined and concentrated to give a pale yellow oily liquid. Adding 3 times of ethanol into the concentrate, freezing and crystallizing at the temperature of minus 10 ℃ to minus 20 ℃ for 6 hours, filtering, leaching the filter cake by using a proper amount of ethanol, and drying to constant weight at the temperature of 30 ℃ to 35 ℃ under normal pressure to obtain a crude product. Then, after dissolving the crude product in 2 volumes of methylene chloride and dissolving the same, 8 volumes of ethanol was added at room temperature, and after stirring at room temperature for 1 hour, the mixture was frozen and crystallized at a temperature of-10 to-20℃for 6 hours, and solids were precipitated and suction-filtered to obtain 22.4g of a white solid (GC purity: 99.5%; yield: 69.3%).

MS：39(6％)、41(35％)、69(100％)、70(5％)、356(15％)、357(3％)、358(5％)。

Synthesis example 2

The method for synthesizing the compound I-1-b is substantially the same as the method for synthesizing the compound I-1-a in example 1, except that: the intermediate compound 1-1 was replaced with compound 2-1.

MS of intermediate compound 2-3: 217 (17%), 219 (5%), 245 (100%), 246 (15%), 247 (32%), 276 (16%), 278 (5%);

MS of compound I-1-b: 41 (13%), 69 (32%), 313 (100%), 314 (20%), 315 (32%), 412 (62%), 413 (16%), 414 (20%).

Synthesis example 3

(1) Preparation of Compound 3-3

To a 500mL three-necked flask, 29g (100 mmol) of Compound 3-1, 45.8g (150 mmol) of Compound 3-2, 250mL of dimethylformamide, 41g (300 mmol) of potassium carbonate and 2.5g (15 mmol) of potassium iodide were added, and the mixture was reacted at a controlled temperature of 80℃to 90℃for 2 hours.

The reaction solution was cooled to room temperature and transferred to a 1L separating funnel. 400mL of water and 200mL of ethyl acetate were added, and the mixture was allowed to stand for separation. The aqueous phase was extracted with 2X 100mL ethyl acetate and the total organic phases were combined. The combined organic phases were washed sequentially with 3X 80mL of water, dried over anhydrous sodium sulfate, and concentrated to give the crude product. Then, petroleum ether was added to the crude product in 3 times volume, and after beating at room temperature for 2 hours, suction filtration was performed to obtain 53g of a white solid (GC purity: 98.5%; yield: 84%).

MS：85(45％)、90(26％)、91(25％)、141(100％)、142(14％)、143(32％)、250(21％)、251(3％)、252(7％)。

(2) Preparation of Compounds 3-4

To a 500mL three-necked flask, 53g (127 mmol) of Compound 3-3 and 200mL of tetrahydrofuran were added. The temperature was controlled below 40 ℃, diluted hydrochloric acid was added dropwise, and the mixture was allowed to react at room temperature of 20 ℃ for 2h.

The reaction solution was adjusted to neutral in pH with aqueous sodium bicarbonate solution. 100mL of ethyl acetate was added and the mixture was separated. The aqueous phase was extracted with 2X 100mL ethyl acetate and the total organic phases were combined. The combined organic phases were washed sequentially with 3X 80mL of water, dried over anhydrous sodium sulfate, and concentrated to give the crude product. Then, 2 times volume of methylene chloride and 4 times volume of petroleum ether were added to the crude product, slurried at room temperature for 1 hour, filtered, and dried to obtain 28g of a white solid (GC purity: 99.2%; yield: 88%).

MS：109(5％)、110(5％)、141(100％)、142(14％)、143(35％)、250(23％)、251(4％)、252(8％)。

(3) Preparation of Compound I-1-c

To a 500mL three-necked flask was added 200mL of methylene chloride, and 28g (112 mmol) of Compound 3-4, 20g (235 mmol) of Compound MAC and 3g (25 mmol) of 4-dimethylaminopyridine were added under nitrogen protection and stirring. The mixture was cooled to 0-10 ℃ and 51.5g (250 mmol) of dicyclohexylcarbodiimide solution (dissolved in 40mL of dichloromethane) was added dropwise while maintaining a temperature of 0-10 ℃. After the dripping is finished, the reaction is carried out for 3 to 4 hours at the temperature of between 0 and 10 ℃.

After the reaction was completed, filtration was performed, and the cake was washed with 50ml×3 dichloromethane. The reaction solution and the washing solution were combined and concentrated to obtain a pale yellow solid. Adding 3 times of ethanol into the concentrate, freezing and crystallizing at the temperature of minus 10 ℃ to minus 20 ℃ for 6 hours, filtering, leaching the filter cake by using a proper amount of ethanol, and drying to constant weight at the temperature of 30 ℃ to 35 ℃ under normal pressure to obtain a crude product. Then, after dissolving the crude product in 2 volumes of methylene chloride and dissolving the same, 8 volumes of ethanol was added at room temperature, and after stirring at room temperature for 1 hour, the solution was frozen and crystallized at a temperature of-10 to-20℃for 6 hours, and solids were precipitated and suction-filtered to obtain 32g of a white solid (GC purity: 99.7%; yield: 74%).

MS：39(6％)、41(35％)、69(100％)、70(5％)、209(52％)、210(7％)、211(17％)、386(14％)、387(3％)、388(5％)。

Synthesis example 4

The method for synthesizing Compound I-5-a was substantially the same as that for synthesizing Compound I-1-a in example 1, except that: the intermediate compound 1-1 was replaced with compound 4-1.

MS of intermediate compound 4-3: 236 (55%), 237 (9%), 238 (18%), 250 (100%), 251 (14%), 252 (32%);

MS of compound I-5-a: 39 (6%), 41 (34%), 69 (100%), 70 (5%), 372 (8%), 374 (3%), 386 (15%), 387 (3%), 388 (5%).

Synthesis example 5

The method for synthesizing Compound I-5-b is substantially the same as that for synthesizing Compound I-1-a in example 1, except that: the intermediate compound 1-1 was replaced with compound 5-1.

MS of intermediate compound 5-3: 127 (12%), 128 (20%), 169 (14%), 171 (6%), 234 (100%), 235 (14%), 236 (33%);

MS of compound I-5-b: 39 (6%), 41 (35%), 69 (100%), 70 (5%), 370 (14%), 371 (3%), 372 (5%).

Synthesis example 6

The method for synthesizing Compound I-12-a was substantially the same as that for synthesizing Compound I-1-a in example 1, except that: the intermediate compound 1-2 was replaced with compound 6-2.

MS of intermediate compound 6-3: 127 (8%), 128 (12%), 155 (5%), 157 (13%), 220 (100%), 221 (14%), 222 (34%);

MS of compound I-12-a: 39 (7%), 41 (41%), 69 (100%), 70 (5%), 356 (20%), 357 (5%), 358 (7%).

Synthesis example 7

(1) Preparation of Compound 7-3

In a 500mL three-necked flask, 22.21g (70 mmol) of Compound 1-1, 19.8g (143.5 mmol) of Compound 7-2, 150mL of toluene, 100mL of ethanol, 100mL of water, 35.28g (420 mmol) of sodium bicarbonate and 0.07g (0.1 mmol) of bis-tert-butyl- (4-dimethylaminophenyl) phosphine palladium (II) dichloride were added. The mixture was subjected to nitrogen substitution 3 times and reacted at a controlled temperature of 60℃to 70℃for 5 hours.

200mL of water was added to the reaction mixture, and a large amount of solids was precipitated. Filtration, adding 500mL petroleum ether to the filter cake, beating once, filtering again, and drying the filter cake at 50℃for 8 hours to give 16.8g of a white solid (GC purity: 99.8%; yield: 80.88%).

MS：148(11％)、149(5％)、202(6％)、231(6％)、296(100％)、297(22％)、298(35％)、299(7％)。

(2) Preparation of Compound I-18-a

To a 500mL three-necked flask, 200mL of methylene chloride was added under nitrogen protection and stirring, and 16.8g (57 mmol) of Compound 7-3, 10.24g (119 mmol) of Compound MAC and 3.45g (28 mmol) of 4-dimethylaminopyridine were added. The mixture was cooled to 0-10℃and 29.16g (142 mmol) of dicyclohexylcarbodiimide solution (dissolved in 30ml of dichloromethane) was added dropwise while maintaining a temperature of 0-10 ℃. After the completion of the dropwise addition, the mixture was naturally warmed to room temperature (20 ℃) and reacted for 5 to 6 hours.

After the reaction was completed, filtration was performed, and the cake was washed with 50ml×3 dichloromethane. The reaction solution and the washing solution were combined, and washed with 200mL of 10wt% diluted hydrochloric acid and 200mL of saturated aqueous sodium bicarbonate, followed by 200mL of 2-Xdeionized water, and finally with 200mL of saturated brine. 10g of anhydrous sodium sulfate was added to the obtained organic phase and dried for 2 hours. After concentration, 200mL of ethanol was added, slurried at room temperature for 2h, and filtered. 200mL of petroleum ether was added to the filter cake, slurried at room temperature for 2 hours, filtered again, and the filter cake was dried at 30℃for 6 hours to give 18.67g of a white solid (GC purity: 99.5%; yield: 75.68%).

MS：39(3％)、41(32％)、69(100％)、70(4％)、432(20％)、433(6％)、434(7％)。

Synthesis example 8

(1) Preparation of Compound 8-3

To a 500mL three-necked flask, 40g (140 mmol) of Compound 8-1, 27g (140 mmol) of Compound 8-2, 250mL of dimethylformamide, 38.6g (280 mmol) of potassium carbonate and 2.3g (14 mmol) of potassium iodide were added, and the mixture was reacted at a controlled temperature of 80℃to 90℃for 2 hours.

The reaction solution was cooled to room temperature, and transferred to a 1L separating funnel. 400mL of water and 200mL of ethyl acetate were added, and the mixture was allowed to stand for separation. The aqueous phase was extracted with 2X 100mL ethyl acetate and the total organic phases were combined. The combined organic phases were washed sequentially with 3X 80mL of water, dried over anhydrous sodium sulfate and concentrated to give the crude product. Then, petroleum ether was added to the crude product in 3 volumes, and after beating at room temperature for 2 hours, suction filtration was performed to obtain 45g of a white solid (GC purity: 99%; yield: 80.8%).

MS：85(43％)、90(25％)、91(25％)、203(77％)、205(100％)、207(24％)、312(16％)、314(21％)、316(5％)。

(2) Preparation of Compound 8-4

To a 500mL three-necked flask, 45g (113 mmol) of Compound 8-3 and 200mL of tetrahydrofuran were added. The temperature was controlled below 40℃and diluted hydrochloric acid was added dropwise to react the mixture at room temperature (20 ℃) for 2h.

The reaction solution was adjusted to neutral in pH with aqueous sodium bicarbonate solution. 100mL of ethyl acetate was added and the mixture was separated. The aqueous phase was extracted with 2X 100mL ethyl acetate and the total organic phases were combined. The combined organic phases were washed sequentially with 3X 80mL of water, dried over anhydrous sodium sulfate, and concentrated to give the crude product. Then, 0.5-fold volume of methylene chloride and 2-fold volume of petroleum ether were added to the crude product, slurried at room temperature for 1 hour, filtered, and dried to obtain 32g of a white solid (GC purity: 99.5%; yield: 90.4%).

MS：109(5％)、110(5％)、203(78％)、205(100％)、207(25％)、312(16％)、314(20％)、316(5％)。

(3) Preparation of Compound 8-5

To a 500mL three-necked flask were added 32g (102 mmol) of Compound 8-4, 14g (102 mmol) of Compound 1-1, 150mL of toluene, 100mL of ethanol, 100mL of water, 16.8g (200 mmol) of sodium bicarbonate and 0.07g (0.1 mmol) of bis-tert-butyl- (4-dimethylaminophenyl) phosphine palladium (II) dichloride. The mixture was subjected to nitrogen substitution 3 times and reacted at a controlled temperature of 60℃to 70℃for 5 hours.

200mL of water was added to the reaction mixture, and a large amount of solids was precipitated. Filtration was carried out, 1-fold volume of methylene chloride and 3-fold volume of petroleum ether were added to the filter cake, slurried once, and filtered again, and the filter cake was dried at 50℃for 8 hours to obtain 31g of a white solid (GC purity: 99.8%; yield: 93%).

MS：109(7％)、110(6％)、217(100％)、218(14％)、219(33％)、326(21％)、327(3％)、328(7％)。

(4) Preparation of Compound I-18-b

To a 500mL three-necked flask, 200mL of methylene chloride was added under nitrogen protection and stirring, and 31g (95 mmol) of Compound 8-5, 17.2g (200 mmol) of Compound MAC and 2.2g (20 mmol) of 4-dimethylaminopyridine were added. The mixture was cooled to 0-10℃and 41.2g (200 mmol) of dicyclohexylcarbodiimide solution (dissolved in 30mL of methylene chloride) was added dropwise while maintaining the temperature at 0-10 ℃. After the dripping is finished, the reaction is carried out for 3 to 4 hours at the temperature of between 0 and 10 ℃.

After the reaction was completed, filtration was performed, and the cake was washed with 50ml×3 dichloromethane. The reaction solution and the washing solution were combined and concentrated to obtain a pale yellow solid. The pale yellow solid is dissolved with dichloromethane, and 8 times volume of ethanol is added, after stirring for 1 hour at room temperature, the mixture is frozen and crystallized for 6 hours at the temperature of minus 10 ℃ to minus 20 ℃, and suction filtration is carried out. After leaching the filter cake with proper amount of ethanol, drying the filter cake to constant weight at the temperature of 30-35 ℃ under normal pressure to obtain a crude product. After dissolving the crude product in methylene chloride and clearing, adding 8 times of volume of ethanol at room temperature, stirring at room temperature for 1 hour, freezing and crystallizing at-10 to-20 ℃ for 6 hours, separating out solid, and suction filtering to obtain 30g of white solid (GC purity: 99.7 percent; yield: 74 percent).

MS：39(6％)、41(35％)、69(100％)、70(5％)、285(45％)、286(7％)、287(15％)、462(19％)、463(6％)、464(7％)。

Referring to the synthesis of the above compounds, other polymerizable compounds of formula I (not described in detail herein) can be obtained by simple substitution of intermediate compounds.

Liquid crystal compositions were prepared in accordance with the proportions of the respective liquid crystal compositions specified in the following examples. The liquid crystal composition is prepared by mixing the components according to a prescribed proportion by a conventional method in the art, such as heating, ultrasonic wave, suspension and the like.

Further description will be made below by mixing different mother liquid crystal compositions with the polymerizable compounds represented by the general formula I of the present invention in Table 2 and the polymerizable compounds widely used in the prior art (C-1, C-2 and C-3) respectively, and testing the respective properties under different conditions.

TABLE 2

/>

Comparative examples 1-2 and examples 1-2

TABLE 3 composition and performance parameters of Host 1

/>

To 100 parts by weight of the above Host 1, a polymerizable compound of the type and parts by weight shown in Table 4 below was added, and Ra, ΔPTA and t were carried out _-20℃ The results of the equal performance test are as follows:

TABLE 4 Table 4

As can be seen from table 4 above, the liquid crystal composition containing the polymerizable compound of formula I of the present invention has significantly lower roughness (i.e., higher uniformity) after polymerization reaction occurs, and its pretilt angle is less changed (i.e., higher stability) by ultraviolet light irradiation and long-term energization, and also has better low-temperature stability and wider application range, as compared with the liquid crystal composition containing the polymerizable compounds C-1, C-2 commonly used in the prior art.

Examples 3 to 6

TABLE 5 composition and performance parameters of Host 2

To 100 parts by weight of the above Host 2, a polymerizable compound of the type and parts by weight shown in Table 5' below was added, and Ra, ΔPTA and t were carried out _-20℃ The results of the equal performance test are as follows:

TABLE 5'

As can be seen from table 5' above, the liquid crystal composition containing the polymerizable compound of the present invention has low roughness (i.e., has high uniformity) after polymerization reaction, and has small variation in pretilt angle (i.e., high stability) due to irradiation with ultraviolet light and long-time energization, good low-temperature stability and wide application range.

Comparative example 3 and examples 7 to 8

TABLE 6 composition and performance parameters of Host 3

To 100 parts by weight of the above Host 3, a polymerizable compound of the type and parts by weight shown in Table 7 below was added, and Ra, ΔPTA and t were carried out _-20℃ The results of the equal performance test are as follows:

TABLE 7

As can be seen from table 7 above, the liquid crystal composition of the present invention containing the polymerizable compound of formula I has significantly lower roughness (i.e., higher uniformity) after polymerization reaction occurs, and its pretilt angle is less changed (i.e., higher stability) by irradiation with ultraviolet light and long-term energization, and also has better low-temperature stability and wider application range, as compared with the liquid crystal composition containing the polymerizable compound C-1 commonly used in the prior art.

Comparative example 4 and examples 9 to 10

TABLE 8 composition and performance parameters for Host 4

To 100 parts by weightTo the above Host 4 of (2), a polymerizable compound of the type and weight part shown in Table 9 below was added, and Ra, ΔPTA and t were carried out _-20℃ The results of the equal performance test are as follows:

TABLE 9

As can be seen from table 9 above, the liquid crystal composition of the present invention containing the polymerizable compound of formula I has significantly lower roughness (i.e., higher uniformity) after polymerization reaction occurs, and its pretilt angle is less changed (i.e., higher stability) by irradiation with ultraviolet light and long-term energization, and also has better low-temperature stability and wider application range, as compared with the liquid crystal composition containing the polymerizable compound C-2 commonly used in the prior art.

In summary, the liquid crystal composition containing the polymerizable compound of the general formula I has the advantages of low roughness (namely, high uniformity) of the polymerized polymer, small change of the pre-tilt angle caused by ultraviolet irradiation and long-time energization (namely, high stability) and good low-temperature stability, can meet the requirement of a large-size PSA type liquid crystal display device on display uniformity, can effectively avoid the occurrence of poor display phenomena such as broken bright spots, and has good application value, and the problem of irregular display caused by the influence of external environment is not easy to occur.

The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the present invention and to implement it, but not limit the scope of the present invention, and all equivalent changes or modifications made according to the spirit of the present invention should be included in the scope of the present invention.

Claims

1. A polymerizable compound of formula I:

the polymerizable compound of formula I is selected from the group consisting of:

and

X ₂ -X ₄ and X ₇ -X ₈ Each independently represents a straight chain alkyl or alkoxy group containing 1 to 5 carbon atoms;

P ₁ and P ₂ Each independently represents

Sp ₁ And Sp ₂ Each independently represents- (CH) ₂ ) _p1 -、-(CH ₂ ) _p1 -O-、-(CH ₂ ) _p1 -O-CO-、-(CH ₂ ) _p1 -CO-O-、-(CH ₂ ) _p1 -O-CO-O-or-CR ⁰ R ⁰⁰ -(CH ₂ ) _p1 -or a single bond, wherein p1 represents an integer from 1 to 12, R ⁰ And R is ⁰⁰ Each independently represents-H, or a linear, branched or cyclic alkyl group containing 1 to 12 carbon atoms;

Z ₁ represents-CH ₂ O-、-OCH ₂ -、-CH ₂ S-、-SCH ₂ -、-CF ₂ O-、-OCF ₂ -、-CF ₂ S-、-SCF ₂ -or a single bond.

2. The polymerizable compound of claim 1 wherein Z ₁ Representing a single bond.

3. A polymerizable compound of formula I selected from the group consisting of:

and

4. A liquid crystal composition comprising one or more polymerizable compounds of the general formula I according to any one of claims 1 to 3.

5. The liquid crystal composition according to claim 4, wherein,

the compound of the general formula I accounts for 0.01-2% of the total weight of the liquid crystal composition.

6. The liquid crystal composition according to claim 4, further comprising one or more compounds of formula M

/>

ring(s)

Ring->

And (C) a ring->

Each independently represents->

Wherein->

One or more of-CH ₂ -can be replaced by-O->

At most one-H of (c) may be substituted by halogen;

n _M1 Represents 0, 1, 2 or 3, wherein when n _M1 When=2 or 3, the ring

Z, which may be the same or different _M2 May be the same or different.

7. The liquid crystal composition according to claim 4, further comprising one or more compounds of formula N

1 or non-adjacent more than 2-CH in the straight-chain or branched alkyl group containing 1-12 carbon atoms ₂ -may each independently be replaced by-ch=ch-, -c≡c-, -O-, -CO-O-, or-O-CO-, and one or more-H present in these groups may each independently be substituted by-F or-Cl;

ring(s)

And (C) a ring->

Each independently represents->

Wherein the method comprises the steps of

One or more of-CH ₂ Can be replaced by-O-andand one or at most two single bonds in the ring may be replaced by double bonds, wherein +.>

Z, which may be the same or different _N1 May be the same or different. />

8. A liquid crystal display device comprising a compound of formula I as defined in any one of claims 1 to 3.

9. A liquid crystal display device comprising the liquid crystal composition of any one of claims 4 to 7.

10. The liquid crystal display device according to claim 8 or 9, wherein the liquid crystal display device is a PSA type liquid crystal display device.