TW202132253A - Liquid crystal composition containing polymerizable compound and application thereof shortening the pre-tilt related response time that can be measured in the test box without obvious damage to other parameters - Google Patents

Abstract

The present invention provides a liquid crystal composition containing a polymerizable compound and its application, comprising one or more of the polymerizable compounds represented by the general formula I, and a nematic liquid crystal composition. In the present invention, by introducing a reactive mesogen (RM) containing three polymerizable groups into the nematic liquid crystal composition, the three polymerizable groups can speed up the reaction speed and time, reduce the process time, improve the alignment effect of the liquid crystal composition, render the polymerization more complete, reduce the residue, and effectively improve the low-temperature miscibility of the liquid crystal composition, thereby reducing the angle-forming time. Especially for the existing PSVA liquid crystal, it can shorten the pre-tilt related response time that can be measured in the test box without obvious damage to other parameters, which has important application value.

Description

Liquid crystal composition containing polymerizable compound and application thereof

The invention relates to the technical field of liquid crystal materials, in particular to a liquid crystal composition containing a polymerizable compound and its application.

The PSVA (Polymer Stable Vertical Alignment Liquid Crystal) type liquid crystal display element forms a structure in which a polymer structure is formed in a liquid crystal cell to control the pretilt angle of liquid crystal molecules, and is used as a liquid crystal display element due to its high-speed response and high contrast. A PSVA-type display element is manufactured by injecting a polymerizable composition containing a liquid crystal compound and a polymerizable compound between the substrates, and polymerizing the polymerizable compound in a state where the liquid crystal molecules are oriented by ultraviolet irradiation. Among them, the polymerizable compound as the main material is of great significance. By matching with a suitable liquid crystal composition, the contrast can be improved, and the problem of display residual image can be solved.

Especially for monitors and TV applications in particular, shortening the process time and optimizing the response time has always been an important issue in the field of research and development. In view of this, the present invention is proposed.

To this end, the present invention provides a liquid crystal composition containing a polymerizable compound and its application. In the present invention, by introducing a reactive mesogen (RM) containing three polymerizable groups into the nematic liquid crystal composition, the three polymerizable groups can speed up the reaction time, reduce the process time, and make the alignment of the liquid crystal composition The effect is better, the polymerization is more complete, the residue is lower, and the low-temperature mutual solubility of the liquid crystal composition can be effectively improved, and the angle-forming time can be reduced. Especially for the existing PSVA liquid crystal, there is no need for other parameters In the case of obvious damage, it can shorten the response time related to the measurable pre-tilt in the test box, which has important application value.

Specifically, the present invention provides a liquid crystal composition containing a polymerizable compound, comprising one or more of the polymerizable compounds represented by the general formula I, and a nematic liquid crystal composition,

Wherein, L ₁ represents H, -F, -C ₁ , -CH ₃ , -C ₂ H ₅ , -OCH ₃ , -OC ₂ H ₅ , -CF ₃ or OCF ₃ ;

P ₁ , P ₂ , and P ₃ independently represent an acrylate group, a methacrylate group, a fluoroacrylate group, a chloroacrylate group, a vinyloxy group, an oxetanyl group, or an epoxy group;

Z ₁ , Z ₂ , and Z ₃ independently represent a single bond, -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, -CH= N-, -N=CH-, -N=N-, C ₁ -C ₁₂ alkylene or C ₂ -C ₁₂ alkenyl; or, the C ₁ -C ₁₂ alkylene or C _{At least one hydrogen atom in the 2-} C ₁₂ alkenyl group is independently substituted by F, Cl or CN; or, one of the C ₁ -C ₁₂ alkylene group or the C ₂ -C ₁₂ alkenyl group -CH ₂ -or at least two non-adjacent -CH ₂ -independently of each other are -O-, -S-, -NH-, -CO-, -CO-O-, -OCO-, -OCOO-, -SCO-, -COS- or -C=C- are replaced by ways that are not directly connected to each other.

Further, in the general formula I, L ₁ represents H, -F, -CH ₃ or -OCH ₃ ;

And/or, P ₁ , P ₂ , and P ₃ independently represent a methacrylate group, an acrylate group, a fluoroacrylate group, or a chloroacrylate group. Preferably, P ₁ , P ₂ , and P ₃ each other Independently represents a methacrylate group or an acrylate group;

And/or, Z ₁ , Z ₂ , and Z ₃ independently represent a single bond, -O-, -S-, -CO-O-, -O-CO-, C ₁ -C ₆ alkylene or C _2- C ₆ alkenyl group; or, _{at least one hydrogen atom in the C 1} -C ₆ alkylene group or C ₂ -C ₆ alkenyl group is substituted by F; or, the C ₁ -C _In the alkylene group of 6 or the alkenyl group of _{C 2} -C _{6 , one -CH 2} -or at least two non-adjacent -CH ₂ -is substituted by -O- in a manner not directly connected to each other; preferably, Z ₁ , Z ₂ , and Z ₃ independently represent a single bond, -O-, C ₁ -C ₆ alkylene;

More preferably, the polymerizable compound represented by the general formula I is selected from one or more of the formulas I1 to I4:

Further, the nematic liquid crystal composition comprises one or more of the compounds represented by the general formula II and one or more of the compounds represented by the general formula III,

Wherein, R ₁ and R ₂ each independently represent a C ₁ -C ₁₂ linear alkyl group, a linear alkoxy group or a C ₂ -C ₁₂ linear alkenyl group, and A ₁ , A ₂ each independently represent a trans 1,4-cyclohexyl or 1,4-phenylene, Z ₄ is a single bond, -CH ₂ CH ₂ -or -CH ₂ O-; a is 0 or 1;

Wherein, R ₃ and R ₄ each independently represent a C _1- C ₁₂ linear alkyl group, a linear alkoxy group or a C ₂ -C ₁₂ linear alkenyl group, and A ₃ , A ₄ each independently represent a trans 1,4-cyclohexyl or 1,4-phenylene.

Further, the compound represented by the general formula II is selected from one or more of IIA~IIF:

Preferably, the compound represented by general formula II is selected from one or more of formula IIA-1~IIF-16:

More preferably, the compound represented by general formula II is selected from formula IIA-9~IIA-24, IIB-19~IIB-38, IIC-9~IIC-24, IID-9~IID-24, IIE-1~IIE -20, one or more of IIF-1~IIF-16;

Most preferably, the compound represented by general formula II is selected from formula IIA-13~IIA-24, IIB-23~IIB-38, IIC-13~IIC-24, IID-13~IID-24, IIE-1, IIE -2, IIE-5, IIE-6, IIE-9, IIE-10, IIE-13, IIE-14, IIE-17, IIE-18, IIF-1, IIF-2, IIF-5, IIF-6 , One or more of IIF-9, IIF-10, IIF-13, IIF-14.

Further, the compound represented by the general formula III is selected from one or more of the formulas IIIA to IIIC:

Preferably, the compound represented by the general formula III is selected from one or more of the formulas IIIA1 to IIIC24:

More preferably, the compound represented by general formula III is selected from one or more of formula IIIA-1~IIIA-22, IIIB-1~IIIB-24, and IIIC-1~IIIC-22;

Most preferably, the compound represented by the general formula III is selected from one or more of the formulae IIIA-1 to IIIA-12, IIIB-17 to IIIB-24, IIIC-1 to IIIC-4, and IIIC-15 to IIIC-18.

Further, the nematic liquid crystal composition further comprises one or more of the compounds represented by the general formula IV:

Wherein, R ₅ and R ₆ each independently represent a C ₁ -C ₁₂ linear alkyl group, a linear alkoxy group or a C ₂ -C ₁₂ linear alkenyl group, and A ₅ represents a trans 1,4-cyclohexyl group Or 1,4-phenylene;

Preferably, the compound represented by the general formula IV is selected from one or more of IVA~IVB:

Wherein, R ₅ and R ₆ each independently represent a C ₁ -C ₇ linear alkyl group, a linear alkoxy group or a C ₂ -C ₇ linear alkenyl group;

More preferably, the compound represented by the general formula IV is selected from one or more of IVA1 to IVB25:

Most preferably, the compound represented by the general formula IV is selected from one or more of IVA-11 to IVA-15, and IVB-11 to IVB-15.

Further, the nematic liquid crystal composition includes the following components by mass percentage:

(1) 1~80% of the compound represented by general formula II;

(2) 1~70% of the compound represented by general formula III;

(3) 0-40% of the compound represented by general formula IV;

Preferably, the nematic liquid crystal composition contains the following components by mass percentage:

(1), 5~70% of the compound represented by general formula II;

(2) 20-60% of the compound represented by general formula III;

(3) 0~35% of the compound represented by general formula IV;

More preferably, the nematic liquid crystal composition contains the following components by mass percentage:

(1) 10~70% of the compound represented by general formula II;

(2) 25-60% of the compound represented by general formula III;

(3) 0~30% of the compound represented by general formula IV;

Further preferably, the nematic liquid crystal composition contains the following components by mass percentage:

(1) 20~70% of the compound represented by general formula II;

(2) 25-50% of the compound represented by general formula III;

(3) 0-20% of the compound represented by general formula IV.

Further, the liquid crystal composition further includes an antioxidant, and the antioxidant includes one or more of the compounds represented by the general formula V:

Wherein, R ₇ represents a C ₁ -C ₇ linear alkyl group, a linear alkoxy group or a C ₂ -C ₇ linear alkenyl group, and A ₆ represents a trans 1,4-cyclohexyl group or 1,4-ylidene group Phenyl; b is 0 or 1;

Preferably, the compound represented by the general formula V is selected from one or two of V-1 to V-2:

And/or, based on the weight of the nematic liquid crystal composition, the compound represented by the general formula V is 0.005 to 1%, preferably 0.005 to 0.1%, and more preferably 0.005 to 0.05%.

Further, based on the weight of the nematic liquid crystal composition, the polymerizable compound represented by the general formula I is 0.01 to 5%, preferably 0.05 to 1%, more preferably 0.1 to 0.5%, more preferably 0.25 to 0.37 %.

The present invention also provides the application of the above-mentioned polymerizable compound-containing liquid crystal composition in a PSVA liquid crystal display device. The liquid crystal composition can shorten the pre-tilt correlation that can be measured in the test box without significant damage to other parameters. The response time has important application value.

The preparation method of the liquid crystal composition of the present invention is not particularly limited. Conventional methods can be used to mix two or more compounds for production, such as by mixing different components at a high temperature and dissolving each other Method of preparation.

The following examples are used to illustrate the present invention, but not to limit the scope of the present invention.

Unless otherwise specified, the percentages in the present invention are percentages by weight; temperature units are degrees Celsius; △n represents optical anisotropy (25°C); ε∥ and ε⊥ represent parallel and perpendicular dielectric constants (25°C, 1000Hz), respectively; △ε represents the dielectric anisotropy (25℃, 1000Hz); γ1 represents the rotational viscosity (mPa.s, 25℃); Cp represents the clearing point (℃) of the liquid crystal composition; K ₁₁ , K ₂₂ , and K ₃₃ represent respectively Spreading, twisting and bending elastic constants (pN, 25°C). ρ represents the resistivity (Ω·cm), and the test condition is 25±2°C.

In the following examples, the group structure in the liquid crystal compound is represented by the code shown in Table 1.

Take the following compound structure as an example:

Expressed as: 3PWO2

Expressed as: 3CCWO2

In the following embodiments, the preparation of the liquid crystal composition adopts the thermal dissolution method, which includes the following steps: weigh the liquid crystal compound by weight percentage with a balance, wherein the order of weighing and addition is not specified, and the melting point of the liquid crystal compound is usually from high to low. Weigh and mix in sequence, heat and stir at 60~100°C to make the components melt uniformly, filter, rotatory steam, and finally encapsulate to obtain the target sample.

The weight percentage of each component in the nematic liquid crystal composition and the performance parameters of the liquid crystal composition are shown in the following table.

Nematic liquid crystal composition LC1

Nematic liquid crystal composition LC2:

Nematic liquid crystal composition LC3

Nematic liquid crystal composition LC4

Nematic liquid crystal composition LC5

Nematic liquid crystal composition LC6

Nematic liquid crystal composition LC7

Nematic liquid crystal composition LC8

Nematic liquid crystal composition LC9

Nematic liquid crystal composition LC10

In the following embodiments, the weight% of RM monomer I and antioxidant are based on the weight of the nematic liquid crystal composition, and are added separately in addition to the mass percentage of the nematic liquid crystal composition.

Examples are shown in Table 12.

The liquid crystal composition containing the polymerizable compound was injected into a PSVA test cell with a cell gap of 3.2 μm by a vacuum injection method. Then, a fluorescent lamp is used to irradiate the liquid crystal cell with ultraviolet rays through a color filter that filters out ultraviolet rays below 310 nm. At this time, the illuminance measured under the condition of the center wavelength of 365 nm was adjusted to be 100 mW/cm2, and ultraviolet rays with a cumulative light amount of 30 J/cm2 were irradiated (irradiation condition 1). Next, using a fluorescent UV lamp, the illuminance measured under the condition of the center wavelength of 313 nm was adjusted to be 3 mW/cm2, and the cumulative amount of light was irradiated to 10 J/cm2 (ultraviolet irradiation condition 2). UV1 is the process of UV irradiation after irradiation condition 1, and UV2 is the process of irradiation condition 1 and irradiation condition 2.

Comparative example 1

To 100 parts by mass of the nematic liquid crystal composition LC1, 0.3 parts by mass of the compound represented by the formula RM-1 and 0.01 parts by mass of the compound represented by the formula V-2 were added to obtain a liquid crystal composition containing a polymerizable compound as Comparative Example 1. .

The liquid crystal composition containing the polymerizable compound was injected into a PSVA test cell with a cell gap of 3.2 μm by a vacuum injection method. Then, a fluorescent lamp is used to irradiate the liquid crystal cell with ultraviolet rays through a color filter that filters out ultraviolet rays below 310 nm. At this time, the illuminance measured under the condition of a center wavelength of 365 nm was adjusted to be 100 mW/cm ² , and ultraviolet rays with a cumulative light amount of 30 J/cm ² were irradiated (irradiation condition 1). Next, using a fluorescent UV lamp, the illuminance measured under the condition of the center wavelength of 313 nm was adjusted to be 3 mW/cm ² , and the cumulative amount of light was irradiated to 10 J/cm ² (ultraviolet irradiation condition 2). UV1 is the process of UV irradiation after irradiation condition 1, and UV2 is the process of irradiation condition 1 and irradiation condition 2.

Effect test

1. Conversion rate of polymerizable compound

A polymerizable compound is added to the composition, and the polymerizable compound is consumed due to polymerization to form a polymer. The conversion rate of this reaction is preferably a large conversion rate.

This is because the residual amount of the polymer compound (the amount of unreacted polymerizable compound) is preferably small from the viewpoint of the residual image of the image.

2. Response time

The response time Toff test, the addition of the trifunctional RM monomer, and the reduction of the response time related to the measurable pre-tilt in the test box can be achieved without significant damage to other parameters, thereby increasing the response speed and reducing the response time .

The test results are shown in Table 13-18.

Compared with Comparative Example 1, the present invention adds RM monomers containing three polymerizable groups. The three polymerizable groups can speed up the reaction time, reduce the process time, increase the response speed, and reduce the response time. Comparative Example 1 The response time is 5.7ms, the maximum response time of the example is 5.5ms, and the minimum is 5.1ms. Compared with Comparative Example 1, the response time is increased by 4%-10% after adding RM monomer containing three polymerizable groups. Time has improved significantly.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: The technical solutions recorded in the foregoing embodiments are modified, or some of the technical features thereof are equivalently replaced; these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims (10)

A liquid crystal composition containing a polymerizable compound, which contains one or more of the polymerizable compounds represented by the general formula I, and a nematic liquid crystal composition,

Wherein, L ₁ represents H, -F, -Cl, -CH ₃ , -C ₂ H ₅ , -OCH ₃ , -OC ₂ H ₅ , -CF ₃ or OCF ₃ ; P ₁ , P ₂ , and P ₃ independently represent an acrylate group, a methacrylate group, a fluoroacrylate group, a chloroacrylate group, a vinyloxy group, an oxetanyl group, or an epoxy group; Z ₁ , Z ₂ , and Z ₃ independently represent a single bond, -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, -CH= N-, -N=CH-, -N=N-, C ₁ -C ₁₂ alkylene or C ₂ -C ₁₂ alkenyl; or, the C ₁ -C ₁₂ alkylene or C _{At least one hydrogen atom in the 2-} C ₁₂ alkenyl group is independently substituted by F, Cl or CN; or, one of the C ₁ -C ₁₂ alkylene group or the C ₂ -C ₁₂ alkenyl group -CH ₂ -or at least two non-adjacent -CH ₂ -independently of each other are -O-, -S-, -NH-, -CO-, -CO-O-, -OCO-, -OCOO-, -SCO-, -COS- or -C=C- are replaced by ways that are not directly connected to each other. The polymerizable compound-containing liquid crystal composition according to claim 1, wherein, in the general formula I, L ₁ represents H, -F, -CH ₃ or -OCH ₃ ; And/or, P ₁ , P ₂ , and P ₃ independently represent a methacrylate group, an acrylate group, a fluoroacrylate group, or a chloroacrylate group. Preferably, P ₁ , P ₂ , and P ₃ each other Independently represents a methacrylate group or an acrylate group; And/or, Z ₁ , Z ₂ , and Z ₃ independently represent a single bond, -O-, -S-, -CO-O-, -O-CO-, C ₁ -C ₆ alkylene or C _2- C ₆ alkenyl group; or, _{at least one hydrogen atom in the C 1} -C ₆ alkylene group or C ₂ -C ₆ alkenyl group is substituted by F; or, the C ₁ -C _In the alkylene group of 6 or the alkenyl group of _{C 2} -C _{6 , one -CH 2} -or at least two non-adjacent -CH ₂ -is substituted by -O- in a manner that is not directly connected to each other; preferably, Z ₁ , Z ₂ , and Z ₃ independently represent a single bond, -O-, C ₁ -C ₆ alkylene; More preferably, the polymerizable compound represented by the general formula I is selected from one or more of the formulas I1 to I4:

The polymerizable compound-containing liquid crystal composition according to claim 1 or 2, wherein the nematic liquid crystal composition contains one or more of the compounds represented by the general formula II, and the compounds represented by the general formula III One or more of

Wherein, R1 and R2 each independently represent a C1-C12 linear alkyl group, a linear alkoxy group or a C2-C12 linear alkenyl group, and A1 and A2 each independently represent a trans 1,4-cyclohexyl group or 1 , 4-phenylene, Z4 is a single bond, -CH2CH2- or -CH2O-; a is 0 or 1;

Wherein, R3 and R4 each independently represent a C1-C12 linear alkyl group, a linear alkoxy group or a C2-C12 linear alkenyl group, and A3 and A4 each independently represent a trans 1,4-cyclohexyl group or 1 , 4-phenylene. The liquid crystal composition containing a polymerizable compound according to claim 3, wherein the compound represented by the general formula II is selected from one or more of IIA to IIF:

Preferably, the compound represented by general formula II is selected from one or more of formula IIA-1~IIF-16:

More preferably, the compound represented by general formula II is selected from formula IIA-9~IIA-24, IIB-19~IIB-38, IIC-9~IIC-24, IID-9~IID-24, IIE-1~IIE -20, one or more of IIF-1~IIF-16; Most preferably, the compound represented by general formula II is selected from formula IIA-13~IIA-24, IIB-23~IIB-38, IIC-13~IIC-24, IID-13~IID-24, IIE-1, IIE -2, IIE-5, IIE-6, IIE-9, IIE-10, IIE-13, IIE-14, IIE-17, IIE-18, IIF-1, IIF-2, IIF-5, IIF-6 , One or more of IIF-9, IIF-10, IIF-13, IIF-14. The liquid crystal composition containing a polymerizable compound according to claim 3 or 4, wherein the compound represented by the general formula III is selected from one or more of the formulas IIIA to IIIC:

Preferably, the compound represented by the general formula III is selected from one or more of the formulas IIIA1 to IIIC24:

More preferably, the compound represented by general formula III is selected from one or more of formula IIIA-1~IIIA-22, IIIB-1~IIIB-24, and IIIC-1~IIIC-22; Most preferably, the compound represented by the general formula III is selected from one or more of the formulae IIIA-1 to IIIA-12, IIIB-17 to IIIB-24, IIIC-1 to IIIC-4, and IIIC-15 to IIIC-18. The polymerizable compound-containing liquid crystal composition according to any one of claims 1-5, wherein the nematic liquid crystal composition further comprises one or more of the compounds represented by the general formula IV:

Wherein, R ₅ and R ₆ each independently represent a C ₁ -C ₁₂ linear alkyl group, a linear alkoxy group or a C ₂ -C ₁₂ linear alkenyl group, and A ₅ represents a trans 1,4-cyclohexyl group Or 1,4-phenylene; Preferably, the compound represented by the general formula IV is selected from one or more of IVA~IVB:

Wherein, R ₅ and R ₆ each independently represent a C ₁ -C ₇ linear alkyl group, a linear alkoxy group or a C ₂ -C ₇ linear alkenyl group; More preferably, the compound represented by the general formula IV is selected from one or more of IVA1 to IVB25:

Most preferably, the compound represented by the general formula IV is selected from one or more of IVA-11 to IVA-15, and IVB-11 to IVB-15. The polymerizable compound-containing liquid crystal composition according to any one of claims 3-6, wherein the nematic liquid crystal composition comprises the following components by mass percentage: (1) 1~80% of the compound represented by general formula II; (2) 1~70% of the compound represented by general formula III; (3) 0-40% of the compound represented by general formula IV; Preferably, the nematic liquid crystal composition contains the following components by mass percentage: (1), 5~70% of the compound represented by general formula II; (2) 20-60% of the compound represented by general formula III; (3) 0~35% of the compound represented by general formula IV; More preferably, the nematic liquid crystal composition contains the following components by mass percentage: (1) 10~70% of the compound represented by general formula II; (2) 25-60% of the compound represented by general formula III; (3) 0~30% of the compound represented by general formula IV; Further preferably, the nematic liquid crystal composition contains the following components by mass percentage: (1) 20~70% of the compound represented by general formula II; (2) 25-50% of the compound represented by general formula III; (3) 0-20% of the compound represented by general formula IV. The liquid crystal composition containing a polymerizable compound according to any one of claims 1-7, wherein the liquid crystal composition further includes an antioxidant, and the antioxidant includes one or more of the compounds represented by the general formula V:

Wherein, R ₇ represents a C ₁ -C ₇ linear alkyl group, a linear alkoxy group or a C ₂ -C ₇ linear alkenyl group, and A ₆ represents a trans 1,4-cyclohexyl group or 1,4-ylidene group Phenyl; b is 0 or 1; Preferably, the compound represented by the general formula V is selected from one or two of V-1 to V-2:

And/or, based on the weight of the nematic liquid crystal composition, the compound represented by the general formula V is 0.005 to 1%, preferably 0.005 to 0.1%, and more preferably 0.005 to 0.05%. The polymerizable compound-containing liquid crystal composition according to any one of claims 1-8, wherein, based on the weight of the nematic liquid crystal composition, the polymerizable compound represented by the general formula I is 0.01-5 %, preferably 0.05 to 1%, more preferably 0.1 to 0.5%, more preferably 0.25 to 0.37%. An application of the polymerizable compound-containing liquid crystal composition according to any one of claims 1-9 in a PSVA type liquid crystal display device.