KR20170040101A - Liquid crystal composition - Google Patents

Abstract

The present invention relates to a liquid crystal composition comprising specific four types of liquid crystal compounds. The liquid crystal composition comprises liquid crystal compounds having the smectic phase or relatively high recrystalline temperature at an optimal ratio, thereby showing various physical properties such as excellent low temperature stability and high clear point. Accordingly, the liquid crystal composition can be properly used for various liquid crystal display devices such as VA, MVA, PVA, PS-VA, PALC, FFS, PS-FFS, IPS, PS-IPS, and the like.

Description

[0001] LIQUID CRYSTAL COMPOSITION [0002]

The present invention relates to a liquid crystal composition exhibiting excellent physical properties such as excellent low temperature stability and high transparency.

A single liquid crystal compound constituting a liquid crystal preparation is an organic material having a molecular weight of about 200 to 600 g / mol and usually has a long rod-like molecular structure. The molecular structure of a liquid crystal compound can be classified into a core group maintaining linearity, a terminal group having flexibility, and a linkage group for specific use. The end group is made up of a flexible (alkyl, alkoxy, alkenyl, etc.) chain that is flexible in one or both sides, while the other side or the side of the central group is introduced with a polar group (F, CN, OCF _3, etc.) Thereby controlling the physical properties of the liquid crystal such as the dielectric constant.

The liquid crystal display (LCD) may be a twist nematic (TN), a super twisted nematic (STN), an in-plane switching (IPS), a fringe field switching (FFS) (Virtical alignment). In such a variety of liquid crystal display devices, it is impossible to make all the required characteristics of a product such as the temperature of the transparent point, the dielectric anisotropy, the refractive index anisotropy, and the rotational viscosity to one or two liquid crystal compounds, The compound is compounded to prepare a liquid crystal composition. The main characteristics required for such a liquid crystal composition are shown in Table 1 below.

Characteristics of Liquid Crystal Display Related to Liquid Crystal Composition Required properties of liquid crystal compositions Reference value Related Liquid Crystal Display Characteristics Low temperature stability Below -20 ℃ Operating temperature Transparent point (T _c ) 70 ℃ or more Operating temperature The dielectric anisotropy (DELTA epsilon) Positive or negative value Threshold voltage, response time Refractive index anisotropy (? N) 0.07 or more Luminance, cell gap The rotational viscosity (? 1) As low as possible Response time The elastic modulus (K ₁₁ , K ₂₂ , K ₃₃ average value) 8 to 18 pN Response time, threshold voltage, brightness

Low temperature stability is one of the main properties that should be considered as the most basic consideration in the production of a liquid crystal composition satisfying the physical properties as shown in Table 1. The melting point of most single liquid crystal compounds is above 30 ° C and needs to be made into compositions based on share points. Another factor affecting low temperature stability is miscibility between materials with large polarity differences in liquid crystal mixtures. Most of the materials have good compatibility with polarity-like materials, but when the polarity difference is large, the compatibility is deteriorated and the tendency to recrystallize is very strong.

Appropriate physical properties in the liquid crystal composition are obtained by mixing a single liquid crystal compound and a polar single liquid crystal compound having a non-polar and low rotational viscosity. In this case, it can be a weak point for low-temperature stability due to compatibility problems. Therefore, a composition capable of solving such a problem is required in a liquid crystal composition through mixing among specific materials.

Accordingly, there is a continuing demand for the development of a liquid crystal composition that exhibits excellent low-temperature stability and satisfies all other physical properties required for liquid crystals such as highly transparent points.

Accordingly, it is an object of the present invention to provide a liquid crystal composition that satisfies other physical properties required for a liquid crystal such as a high transparent point, together with excellent low temperature stability.

The present invention relates to a composition comprising 5 to 50% by weight of a compound of formula (1); From 1.5 to 25% by weight of the compound of formula (2); From 10 to 55% by weight of the compound of formula (III); And 2 to 25% by weight of the compound of formula (4):

[화학식 1]

[Chemical Formula 1]

[화학식 2]

(2)

[화학식 3]

(3)

[화학식 4]

[Chemical Formula 4]

In the above formula (1), R ₁ is an alkyl group having 1 to 7 carbon atoms, and o is an integer of 0 or 1.

Hereinafter, a liquid crystal composition according to embodiments of the present invention and a liquid crystal display device including the same will be described in detail.

As described above, the liquid crystal composition of one embodiment includes the specific liquid crystal compounds of the formulas (1) to (4).

The liquid crystal composition of this embodiment can achieve better low temperature stability in the mixing of a liquid crystal compound having a low rotational viscosity with a material having a dielectric anisotropy close to 0 and a substance having a dielectric anisotropy of 20 or more. As a result of continuous experiments by the present inventors, it has been found that when mixing liquid crystal compounds having the above-described dielectric anisotropy and rotational viscosity, specific liquid crystal compounds having a smectic phase or relatively high recrystallization temperature are selected and mixed at an optimum ratio , It has been found that a liquid crystal composition exhibiting excellent low temperature stability can be provided while satisfying various properties required for liquid crystals such as high transparency, suitable anisotropy and low rotational viscosity, and completed the invention.

Hereinafter, each component of the liquid crystal composition of this embodiment will be described in more detail.

First, the compound represented by the formula (1) is a liquid crystal compound exhibiting a high dielectric anisotropy, and the three-ring liquid crystal compound included therein may exhibit a dielectric anisotropy of 20 or more and the four- In addition, such a component has a low rotational viscosity relative to anisotropy of dielectric anisotropy, so that the response time of the LCD can be reduced and the driving voltage can be lowered.

However, considering the high refractive index anisotropy of 0.2 or more of the above components, the compound of the formula (1) may be contained in an amount of 5 to 50% by weight, more preferably 5 to 40% by weight in the entire liquid crystal composition. Since the compound of Formula 1 is contained in an amount of 5 to 40% by weight, the liquid crystal composition of one embodiment has a more optimized anisotropy of dielectric anisotropy and refractive index and can maintain a low rotational viscosity and contribute to a fast response speed.

From the viewpoints of anisotropy and low rotational viscosity of the compound of formula (1), R ₁ is preferably an ethyl group or a propyl group as the compound of formula (1).

The compound of formula (2) contained in the liquid crystal composition of one embodiment has a low dielectric anisotropy and a low rotational viscosity as compared with a transparent point, and can contribute to anisotropy and fast response speed of the liquid crystal composition. Further, the compound of formula (2) has a clearing point of 150 캜 or higher, which can contribute to keeping the transparent point of the liquid crystal composition and the corresponding operating temperature at 70 캜 or higher.

Considering the high transparency of the liquid crystal composition, low rotational viscosity, and appropriate dielectric anisotropy, the compound of Formula 2 may be contained in an amount of 1.5 to 25% by weight based on the total liquid crystal composition. More preferably, the compound of Formula 2 may be contained in an amount of from 1.5 to 15% by weight, thereby inhibiting recrystallization of the compound of Formula 2 in the liquid crystal composition while contributing to various properties of the liquid crystal composition. In addition, the low-temperature stability and reliability of the liquid crystal composition can be further improved due to the preferable content range of the above-described formula (2).

On the other hand, the compound of the formula (3) has low rotational viscosity of 20 m Pa · s or less and has been used in various liquid crystal compositions. Such a compound is contained in an amount of 10 to 55% by weight, and can contribute to low rotational viscosity and fast response speed of the liquid crystal composition. More preferably, the compound of Formula 3 may be contained in an amount of 10 to 45% by weight, or 25 to 45% by weight, or 30 to 45% by weight, whereby the low temperature stability and reliability of the liquid crystal composition can be further improved.

On the other hand, the liquid crystal composition of one embodiment includes the compound of the formula (4) together with the compounds of the formulas (1) to (3). The anisotropy, the rotational viscosity, and the transparency of the liquid crystal composition can be controlled to some extent by mixing the compounds of the formulas (1) to (3). However, in this case, the polarizability of each component can easily be recrystallized or low temperature stability . However, the composition of one embodiment further contains a certain amount of the compound of the general formula (4), so that it can exhibit better low temperature stability while appropriately controlling all the above physical properties.

In Table 2, the physical properties of the representative examples of the formula (1) are shown in comparison with the formulas (2) to (4).

division rescue Phase transition temperature (° C) Dielectric anisotropy Formula 1

C 74.3 N 122.9 I 31 (2)

C 41.6 S 105.6 N 178.5 I 0.5 (3)

C-15 S 32 N 48 I -0.3 Formula 4

C 92 N 241.4 I 15

In Table 2, "C" in the phase transition temperature item denotes a crystal, "S" denotes a smectic, "N" denotes a nematic, "I" denotes a liquid phase, Is the temperature at which the state of the material changes.

As can be seen from Table 2, the specific examples of the compound of Formula 1 have a dielectric anisotropy of 31, and the compounds of Formula 2 and 3 have a dielectric anisotropy close to zero. However, when a liquid crystal composition is provided with such a substance having a large difference in polarity, the miscibility of each component is rapidly deteriorated, and recrystallization may occur or low temperature stability and reliability of the liquid crystal composition may be significantly deteriorated. In addition, since the liquid crystal composition used in the LCD is usually a nematic phase, the low temperature stability of the liquid crystal composition may be lowered when a material exhibiting a stymatic phase is mixed as shown in the following formulas (2) and (3).

However, when the compounds of the general formula (4) are used together with the compounds of the general formulas (1) to (3), the miscibility of the respective components can be improved. As a result, the liquid crystal composition of one embodiment can have excellent low temperature stability and reliability . For reference, the compound of Formula 4 may be included in an amount of 2 to 25% by weight, and the low temperature stability of the liquid crystal composition can be improved by incorporating the compound in such an amount. The compound of formula (4) may more suitably be contained in an amount of 2 to 15% by weight, thereby improving the low-temperature stability of the liquid crystal composition. However, the compound of formula (4) Can be appropriately suppressed. Further, by controlling the content range of the compound of the formula (4), a liquid crystal composition having a desired transparent point can be obtained. For example, when the content range of the compound of the general formula (4) is increased to 10 wt% or more, a liquid crystal composition having a higher transparent point, for example, a transparent point of 90 DEG C or higher may be obtained.

The liquid crystal composition of one embodiment containing the compounds of the formulas (1) to (4) described above satisfies the dielectric anisotropy of 3 to 14, the transparent point of 70 DEG C or more, the rotational viscosity of 40 to 120 mPa s, , But it can be shown to exhibit improved low temperature stability.

On the other hand, the liquid crystal composition of one embodiment described above may further contain 3 to 20% by weight of the compound of the following formula (5)

[화학식 5]

[Chemical Formula 5]

In Formula 5, R ₂ and R ₃ are each independently an alkyl group having 1 to 5 carbon atoms.

By further using the compound of the formula (5), it is possible to more effectively control the transparent point of the liquid crystal composition to an appropriate range. For example, for a liquid crystal composition exhibiting a predetermined dielectric anisotropy (for example, 8.3 to 9.9) as supported by the following embodiments, a liquid crystal composition having a high transparency point can be obtained by using the compound of the formula (5) Can be obtained. In view of such control of the clearing point, compounds of the above formula (5) include those wherein R ₂ and R ₃ are each an alkyl group having 2 to 5 carbon atoms, more specifically, R ₂ is an alkyl group having 3 to 5 carbon atoms, and R ₃ is an ethyl group Can be suitably used. Also, considering the aspect of the above-mentioned transparent point control and the compound of the formula (5) has a strong smectic tendency, the compound of the formula (5) may be contained in an amount of 3 to 20% by weight.

In addition, the liquid crystal composition of one embodiment may further include at least one compound selected from the group consisting of the following formulas (6) to (9) to further control the required properties, for example, anisotropy, have:

[화학식 6]

[Chemical Formula 6]

[화학식 7]

(7)

[화학식 8]

[Chemical Formula 8]

[화학식 9]

[Chemical Formula 9]

In the general formulas (6) to (9), R ₄ to R ₈ are each independently an alkyl group having 1 to 7 carbon atoms, or 1 to 3 H groups contained in the alkyl group are substituted with halogen or one or more -CH ₂ - Is a radical substituted with -C≡C-, -CF ₂ O-, -CH = CH-, -O-, -CO-O-, -O-CO- or -O-CO-O- ,

Y ₁ is an alkyl group having 1 to 7 carbon atoms, F, or -OCF ₃ ,

Y ₂ and Y ₃ are each independently F, -OCF ₃ or -CF ₃ ,

Ring A, ring B, ring C, ring E and ring G are each independently cyclohexylene or phenylene,

Ring D, ring F and ring H are each independently cyclohexylene, phenylene or fluorophenylene,

(F) may be substituted or unsubstituted with fluorine.

In this additional liquid crystal compound, Formula (6) has a structure different from Formula (3), Formula (7) has a structure different from Formula (2) and Formula (5), and Formula (9) may have a structure different from Formula (4). That is, the liquid crystal compounds of the formulas (6) to (9) may have a chemical structure different from those of the above formulas (1) to (5) as components to be added for further controlling the physical properties of the liquid crystal composition separately from the compounds .

The compounds of the formulas (6) to (9) can be selected and added by those skilled in the art depending on the type and degree of the liquid crystal properties to be controlled, and the content ranges thereof are also the same as those of the above- By a person skilled in the art. For example, the compounds of the formulas (6) to (9) may be appropriately selected and added by those skilled in the art within a range of 5 to 80% by weight of the total liquid crystal composition.

In order to more appropriately control the required properties of the liquid crystal composition of one embodiment, in the above formula (6), R ₄ and R ₅ each independently represent an alkyl group having 2 to 5 carbon atoms, for example, a propyl group or a butyl group, have.

As the compound of Formula 7, ring C is phenylene, ring D is fluorophenylene, R ₆ is an alkyl group having 1 to 7 carbon atoms, Y ₁ is an alkyl group having 1 to 7 carbon atoms or F, And / or ring C and ring D are cyclohexylene, R ₆ is an alkyl group having 1 to 7 carbon atoms, and Y ₁ is -OCF ₃ .

As the compound of Formula 8, it is preferable that the ring E is cyclohexylene, the ring F is cyclohexylene or phenylene, R ₇ is an alkyl group having 1 to 7 carbon atoms, and Y ₂ is F have.

In addition to the liquid crystal compounds described above, the liquid crystal composition may further include various additives conventionally used in the art to which the present invention belongs. Specifically, the liquid crystal composition may further include an antioxidant or a UV stabilizer. As such a UV stabilizer, Hals (Hindered amine light stabilizer) series can be used. However, the kind of the additive usable in the liquid crystal composition is not particularly limited, and the kind thereof is known to a person skilled in the art, and a further explanation thereof will be omitted.

The liquid crystal composition described above can be used for AM-LCD (Active Matrix-LCD) or PM-LCD (Passive Matrix-LCD) and can be used for VA, MVA, PVA, PS-VA, PALC, FFS, PS- Or a liquid crystal display of various modes such as PS-IPS.

According to another embodiment of the present invention, there is provided a liquid crystal display comprising the liquid crystal composition described above. The liquid crystal composition can be applied to a liquid crystal display device through various methods known in the art. Also, the liquid crystal display device may be manufactured by a liquid crystal display device having various modes as described above.

The present invention can provide a liquid crystal composition exhibiting improved low-temperature stability and reliability while satisfying appropriate properties as liquid crystal such as high transparency, low rotational viscosity and suitable anisotropy. Such a liquid crystal composition can be suitably used in various liquid crystal display devices.

Hereinafter, preferred embodiments of the present invention will be described in order to facilitate understanding of the present invention. However, the following examples are provided only for the purpose of easier understanding of the present invention, and the present invention is not limited thereto. In the following Examples and Comparative Examples, the notation of the liquid crystal compound is shown in Table 3 below.

Example  And Comparative Example

The physical properties of the liquid crystal compositions prepared in Examples and Comparative Examples were evaluated according to the methods described below. Unless otherwise specified, the properties of the liquid crystal compositions were measured without adding other additives to the liquid crystal compositions prepared in Examples and Comparative Examples.

(1) Transparent point (Tni)

The liquid crystal composition for which the transparent point was to be measured was dropped with a drop on the slide glass with a sphere and covered with a cover glass to prepare a sample for measurement of the transparent point.

The sample was placed in an instrument equipped with a METTLER TOLEDO FP90 temperature regulator and the change in sample was monitored by raising the temperature at a rate of 3 ° C / min with an FP82HT hot stage. The temperature at the point where the hole was formed in the sample was recorded, and this operation was repeated three times to derive an average value. This value was defined as the transparent point of the liquid crystal composition.

(2) Refractive Index Anisotropy (n)

The refractive index anisotropy (n) of the liquid crystal composition was measured with an Abbe refractometer equipped with a polarizing plate on an eyepiece using light having a wavelength of 589 nm at 20 ° C. After the surface of the main prism was rubbed in one direction, the liquid crystal composition to be measured was dropped on the main prism. Thereafter, the refractive index (n∥) when the direction of the polarized light was parallel to the liquid crystal long axis and the refractive index (n⊥) when the polarizing direction was perpendicular to the liquid crystal short axis direction were measured. Then, the refractive index anisotropy (n) was measured by substituting the refractive index value into the equation (1).

[Formula 1]

n = n? - n?

(3) Dielectric constant anisotropy (??)

The dielectric anisotropy (?) Of the liquid crystal composition was calculated by substituting the values of?

[Formula 2]

Δε = ε∥ - ε⊥

(1) Measurement of dielectric constant??: A vertical alignment agent was applied to the surface of the two glass substrates on which the ITO pattern was formed to form a vertical alignment film. Subsequently, the spacers were coated on one of the two glass substrates so that the vertical alignment films faced each other and the interval (cell gap) between the two glass substrates was 4 占 퐉, and then the two glass substrates were bonded together. Then, the liquid crystal composition to be measured was poured into the device and sealed with an adhesive which is cured by ultraviolet rays. The dielectric constant ([epsilon]) of the device at 1 kHz, 0.3 V and 20 [deg.] C was then measured using a 4294A instrument manufactured by Agilent.

(2) Measurement of dielectric constant??: A horizontal alignment agent was applied to the surface of the two glass substrates on which the ITO pattern was formed to form a horizontal alignment film. Subsequently, the spacers were coated on one of the two glass substrates so that the horizontal alignment films faced each other and the interval (cell gap) between the two glass substrates was 4 占 퐉, and then the two glass substrates were bonded together. Then, the liquid crystal composition to be measured was poured into the device and sealed with an adhesive which is cured by ultraviolet rays. Thereafter, the dielectric constant (ε⊥) of the device at 1 kHz, 0.3 V, and 20 ° C was measured using a 4294A instrument manufactured by Agilent.

(4) Rotational viscosity (?)

A horizontal alignment agent was applied to the surface of the two glass substrates on which the ITO pattern was formed to form a horizontal alignment film. Then, the spacers were coated on any one of the two glass substrates so that the horizontal alignment films faced each other and the interval (cell gap) between the two glass substrates was 20 占 퐉, and then the two glass substrates were bonded together. Then, a liquid crystal composition was injected into the device, and the device was sealed with an adhesive that cures by ultraviolet rays. The rotational viscosity of the device was then measured at 20 ° C using a Model 6254 instrument from Toyo Corp. equipped with a temperature controller (Model SU-241) manufactured by ESPEC Corp.

(5) Low temperature stability

2 g of the liquid crystal was placed in a 10 mL vial and allowed to stand in a freezer at -30 캜 for one day to determine whether it was crystalline or smectic for 5 days. "NG" for the number of days observed and "7 days OK" for the case of maintaining the nematic phase for 7 days were recorded when crystals or smectic were generated several days later.

According to the compositions of Tables 4 to 7, liquid crystal compositions of Examples 1 to 25 and Comparative Examples 1 to 8 were prepared. The physical properties of each liquid crystal composition were evaluated by the above-described method and are shown in Tables 4 to 7 together. For reference, in the following Tables 4 to 7, the content of each component is expressed in "% by weight ".

division Item Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 The
One AEXE1-3.F 0.0 0.0 0.0 0.0 11.0 7.0 10.0 10.0 0.0 10.0 ACEXE1-2.F 0.0 2.0 7.8 7.3 0.0 0.0 0.0 0.0 0.0 0.0 ACEXE1-3.F 0.0 0.0 7.8 6.8 0.0 0.0 0.0 0.0 7.0 0.0 The
2 BBA-3.1 0.0 4.0 2.0 9.6 8.0 7.0 6.0 6.0 6.0 6.0 The
3 BB-3.V 22.0 25.0 58.8 43.5 40.0 35.0 40.0 40.0 45.0 45.0 The
4 BBCE-3.F 0.0 0.0 1.5 0.0 3.0 3.0 3.0 5.0 3.0 5.0 The
5 BAA-3.1 0.0 0.0 0.0 5.1 0.0 0.0 0.0 0.0 0.0 0.0 BAA-3.2 0.0 0.0 4.9 5.1 0.0 5.0 5.0 5.0 3.0 0.0 BB-3.U1 0.0 0.0 4.9 9.9 0.0 5.0 5.0 6.0 8.0 5.0 Other BBA-V.1 0.0 0.0 0.0 3.6 0.0 6.0 5.0 5.0 3.0 3.0 BB-3.4 12.0 11.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 ACA-3.F 12.0 10.0 0.0 0.0 5.0 4.0 4.0 4.0 4.0 4.0 ACA-5.F 0.0 0.0 0.0 0.0 0.0 3.0 3.0 3.0 3.0 3.0 BAC-3.F 11.0 11.0 0.0 0.0 5.0 0.0 0.0 0.0 0.0 0.0 BAE-3.F 6.0 6.0 0.0 0.0 5.0 8.0 5.0 5.0 5.0 5.0 BBE-3.F 15.0 10.0 0.0 4.8 5.0 5.0 5.0 5.0 5.0 3.0 BBE-2.F 6.0 6.0 0.0 0.0 0.0 7.0 4.0 4.0 4.0 4.0 BBA-3.OCF3 8.0 7.5 0.0 4.3 9.0 5.0 5.0 0.0 4.0 4.0 BBA-5.OCF3 8.0 7.5 0.0 0.0 9.0 0.0 0.0 0.0 0.0 0.0 BCAB-3.3 0.0 0.0 7.4 0.0 0.0 0.0 0.0 2.0 0.0 3.0 Properties Low temperature stability 1 day
NG 1 day
NG 5 days
NG 2 days
NG 7 days
OK 7 days
OK 7 days
OK 7 days
OK 7 days
OK 7 days
OK Clear point (℃) 77.0 86.3 85.7 90.6 82.4 82.2 77.0 80.6 81.5 76.7 Refractive index anisotropy 0.098 0.099 0.095 0.095 0.092 0.097 0.094 0.097 0.093 0.090 Dielectric anisotropy 5.4 5.4 4.4 4.7 5.8 5.1 5.0 5.1 4.7 5.0 Rotational viscosity
(m Pa s) 80 84 70 73 65 69 56 57 60 60

division Item Comparative Example 5 Comparative Example 6 Example 7 Example 8 Example 9 Example 10 Example 11 Example 12 Formula 1 AEXE1-3.F 0.0 0.0 7.0 10.0 10.0 11.0 7.0 8.0 ACEXE1-2.F 0.0 0.0 4.0 10.0 10.0 5.0 6.0 9.0 ACEXE1-3.F 0.0 8.0 8.0 0.0 0.0 6.0 10.0 8.0 (2) BBA-3.1 0.0 8.0 8.0 5.0 10.0 9.0 7.0 5.0 (3) BB-3.V 12.0 18.0 35.0 30.0 25.0 28.0 37.0 42.0 Formula 4 BBCE-3.F 0.0 0.0 5.0 4.0 5.0 5.0 5.0 3.0 Formula 5 BAA-3.2 0.0 0.0 0.0 5.0 5.0 4.0 4.0 6.0 BAA-5.2 0.0 0.0 0.0 0.0 0.0 0.0 4.0 0.0 Other BB-3.U1 0.0 0.0 0.0 5.0 7.0 6.0 0.0 0.0 BBA-V.1 0.0 0.0 0.0 0.0 0.0 4.0 4.0 4.0 ACA-3.F 7.0 6.0 6.0 5.0 5.0 0.0 0.0 0.0 BAC-3.F 10.0 4.0 3.0 3.0 3.0 3.0 0.0 0.0 BAE-3.F 15.0 15.0 9.0 10.0 10.0 10.0 7.0 0.0 BBE-3.F 15.0 15.0 9.0 5.0 5.0 5.0 5.0 3.0 BBE-2.F 15.0 15.0 0.0 0.0 0.0 0.0 0.0 3.0 ACE-5.F 8.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 BBA-3.OCF3 5.0 3.0 3.0 5.0 5.0 4.0 4.0 6.0 BBA-5.OCF3 13.0 8.0 3.0 0.0 0.0 0.0 0.0 0.0 BCAB-3.3 0.0 0.0 0.0 3.0 0.0 0.0 0.0 3.0 Properties Low temperature stability 1 day
NG 1 day
NG 7 days
OK 7 days
OK 7 days
OK 7 days
OK 7 days
OK 7 days
OK Clear point (℃) 82.6 85.4 79.3 88.2 85.9 88.7 89.2 87.2 Refractive index
Anisotropy 0.110 0.106 0.109 0.114 0.115 0.108 0.109 0.104 permittivity
Anisotropy 8.6 8.9 9.1 9.0 9.3 9.2 9.9 8.3 Rotational viscosity
(m Pa s) 122 114 83 92 100 90 112 82

division Item Comparative Example 7 Comparative Example 8 Example 13 Example 14 Example 15 Example 16 Example 17 Example 18 Formula 1 AEXE1-3.F 3.0 3.0 2.9 2.9 2.8 2.7 2.6 2.5 ACEXE1-3.F 7.0 6.9 6.9 6.7 6.5 6.3 6.2 6.0 (2) BBA-3.1 1.0 1.0 2.0 1.9 1.9 1.8 1.8 1.7 (3) BB-3.V 39.0 38.6 38.2 37.0 36.0 35.1 34.3 33.1 Formula 4 BBCE-3.F 0.0 1.0 2.0 4.8 7.4 10.0 12.0 15.1 Formula 5 BAA-3.2 7.0 6.9 5.9 5.7 5.6 5.4 5.3 5.1 BAA-5.2 3.0 3.0 2.9 2.9 2.8 2.7 2.6 2.5 Other BB-3.4 8.0 7.9 7.8 7.6 7.4 7.2 7.0 6.8 ACA-3.F 6.0 5.9 5.9 5.7 5.6 5.4 5.3 5.1 ACA-5.F 6.0 5.9 5.9 5.7 5.6 5.4 5.3 5.1 BBA-3.OCF3 3.0 3.0 2.9 2.9 2.8 2.7 2.6 2.5 BAE-3.F 5.0 5.0 4.9 4.8 4.6 4.5 4.4 4.3 BAC-3.F 12.0 11.9 11.8 11.4 11.0 10.8 10.6 10.2 Properties Low temperature stability 1 day
NG 2 days
NG 7 days
OK 7 days
OK 7 days
OK 7 days
OK 7 days
OK 7 days
OK Clear point (℃) 79 80.2 81.4 84.4 87.5 90.7 92.1 95.2 Refractive index anisotropy 0.113 0.114 0.114 0.116 0.117 0.118 0.118 0.119 Dielectric anisotropy 5.3 5.4 5.4 5.8 6.1 6.4 6.4 6.5 Rotational viscosity
(m Pa s) 52 55 51 64 69 75 77 80

division Item Example 19 Example 20 Example 21 Example 22 Example 23 Example 24 Example 25 Formula 1 AEXE1-3.F 5.6 5.4 5.2 5.0 5.7 5.7 5.7 ACEXE1-2.F 16.4 15.9 15.2 14.7 16.7 16.7 16.7 ACEXE1-3.F 2.0 1.9 1.8 1.8 2.0 2.0 2.0 (2) BBA-3.1 4.9 4.8 4.5 4.4 5.0 5.0 5.0 (3) BB-3.V 36.2 35.2 33.7 32.5 37.1 37.1 37.1 Formula 4 BBCE-3.F 2.0 4.8 9.2 12.0 2.0 5.0 10.0 Formula 5 BAA-3.2 4.9 4.8 4.5 4.4 5.0 5.0 5.0 Other ingredients ACA-2.3 2.0 1.9 1.8 1.8 2.0 2.0 2.0 ACA-2.F 2.0 1.9 1.8 1.8 2.0 2.0 2.0 BBA-3.OCF3 9.0 8.8 8.4 8.1 9.2 9.2 9.2 BBE-2.F 2.8 2.8 2.6 2.6 1.5 BBE-3.F 7.5 7.2 6.9 6.7 7.0 7.0 2.0 BAE-3.F 4.7 4.6 4.4 4.2 4.8 3.3 3.3 Properties Low temperature stability 7 days
OK 7 days
OK 7 days
OK 7 days
OK 7 days
OK 7 days
OK 7 days
OK Clear point (℃) 82.9 86.6 92.5 96.3 84.0 88.3 94.2 Refractive index anisotropy 0.1148 0.1161 0.1178 0.1195 0.1154 0.1175 0.1215 Dielectric anisotropy 7.7 7.8 10.1 11.1 11.0 10.8 11.1 Rotational viscosity
(m Pa s) 58 61 83 109 100 97 101

In Table 4, the liquid crystal compositions of the comparative examples in which one or more of the compounds represented by the general formulas (1) to (4) are not present, or the content range thereof is insufficient, and the compounds of the general formulas (1) to (4) In the comparative examples of these liquid crystal compositions, the compositions were compared on the basis of a composition having a dielectric anisotropy of 4.4 to 5.8. The results of the experiment of Table 4 indicate that the compounds of the formulas (1) to (4) can be used in an appropriate content range (for example, at least 5% by weight of the formula 1, at least 30% by weight of the formula 3, , It was confirmed that they exhibited a similar lower dielectric constant anisotropy and lower rotational viscosity than the comparative example. In addition, in Comparative Example 3, the liquid crystal compositions of Examples were found to exhibit excellent low-temperature stability, while showing poor low-temperature stability as the content range of the compounds of Formulas 2 to 4 was out of an appropriate range.

In Table 5, the compositions were compared based on compositions having a dielectric anisotropy of 8.3 to 9.9. Referring to the experimental results of Table 5, it was confirmed that the rotational viscosities of Examples 7 to 12 were lower than those of Comparative Examples 5 and 6, and the low temperature stability was improved. Further, in Examples 8 to 12, the temperature of the transparent point was 85 ° C. or higher, compared with Example 7. It can be seen that the compound of formula (5) can be further adjusted for the high-temperature transparent point.

Table 6 compares the low temperature stability according to the presence or the content of the compound of the formula (4). In Comparative Example 7 8 in which the content of the compound of Formula 4 was less than 2% by weight, it was confirmed that the low-temperature stability was poor for 2 days or less. However, in Examples 13 to 18 in which the compound of Formula 4 was used in an amount of 2 wt% or more, it was confirmed that it exhibited improved low temperature resistance. It was confirmed that the liquid crystal compositions of Examples 16 to 18 in which the compound of the formula (4) was used in an amount of 10% by weight or more could have a transparent point of 90 ° C or higher.

Table 7 shows liquid crystal compositions having various dielectric anisotropy. It has been confirmed that the liquid crystal compositions of the Examples which contain the compounds of the formulas (1) to (4) as essential components in the appropriate content range are excellent in low temperature stability and exhibit a low rotational viscosity.

Claims (7)

From 5 to 50% by weight of the compound of formula (1);
From 1.5 to 25% by weight of the compound of formula (2);
From 10 to 55% by weight of the compound of formula (III); And
A liquid crystal composition comprising 2 to 25% by weight of a compound of formula (4)

[Chemical Formula 1]

(2)

(3)

[Chemical Formula 4]
In the above formula (1), R ₁ is an alkyl group having 1 to 7 carbon atoms, and o is an integer of 0 or 1.
The liquid crystal composition according to claim 1, wherein R ₁ is an ethyl group or a propyl group.
The liquid crystal composition according to claim 1, further comprising 3 to 20% by weight of the compound of the formula (5)

[Chemical Formula 5]
In Formula 5, R ₂ and R ₃ are each independently an alkyl group having 1 to 5 carbon atoms.
The liquid crystal composition according to any one of claims 1 to 3, further comprising at least one compound selected from the group consisting of formulas (6) to (9)

[Chemical Formula 6]

(7)

[Chemical Formula 8]

[Chemical Formula 9]

In the general formulas (6) to (9), R ₄ to R ₈ are each independently an alkyl group having 1 to 7 carbon atoms, or 1 to 3 H groups contained in the alkyl group are substituted with halogen or one or more -CH ₂ - Is a radical substituted with -C≡C-, -CF ₂ O-, -CH = CH-, -O-, -CO-O-, -O-CO- or -O-CO-O- ,
Y ₁ is an alkyl group having 1 to 7 carbon atoms, F, or -OCF ₃ ,
Y ₂ and Y ₃ are each independently F, -OCF ₃ or -CF ₃ ,
Ring A, ring B, ring C, ring E and ring G are each independently cyclohexylene or phenylene,
Ring D, ring F and ring H are each independently cyclohexylene, phenylene or fluorophenylene,
(F) can be substituted or unsubstituted with fluorine,
Formula (6) has a structure different from Formula (3), Formula (7) has a structure different from Formulas (2) and (5), and Formula (9) has a structure different from Formula (4).
5. The liquid crystal composition according to claim 4, wherein in Formula 6, R ₄ and R ₅ are each independently an alkyl group having 2 to 5 carbon atoms.
5. The compound according to claim 4, wherein in formula (7)
Ring C is phenylene, ring D is fluorophenylene, R ₆ is an alkyl group having 1 to 7 carbon atoms, Y ₁ is an alkyl group having 1 to 7 carbon atoms or F,
Ring C and ring D are cyclohexylene, R ₆ is an alkyl group having 1 to 7 carbon atoms, and Y ₁ is -OCF ₃ .
The liquid crystal composition according to claim 4, wherein in the formula (8), the ring E is cyclohexylene, the ring F is cyclohexylene or phenylene, R ₇ is an alkyl group having 1 to 7 carbon atoms, and Y ₂ is F.