WO2020044832A1

WO2020044832A1 - Composition and liquid crystal display element using same

Info

Publication number: WO2020044832A1
Application number: PCT/JP2019/028244
Authority: WO
Inventors: 士朗谷口; 偉呉; 晴己大石
Original assignee: Dic株式会社
Priority date: 2018-08-29
Filing date: 2019-07-18
Publication date: 2020-03-05
Also published as: JPWO2020044832A1; CN112352032A

Abstract

The present invention provides a liquid crystal composition which has a positive ∆ε, a liquid phase over a wide temperature range, a low viscosity, good solubility at low temperatures, a high specific resistance and a high voltage holding ratio, while being stable to heat and light, and which additionally has a high elastic constant and a relatively high ε﬩. The present invention provides a liquid crystal composition which contains a component (A) that is composed of compounds having positive dielectric anisotropy, said compounds including at least one compound that is selected from among those represented by general formula (A1), a component (B) that is composed of compounds having negative dielectric anisotropy, said compounds including at least one compound that is selected from among those represented by general formula (B1), and a component (C) that is composed of dielectrically neutral compounds including at least one compound that is selected from among those represented by general formula (C1), said liquid crystal composition having positive dielectric anisotropy as a whole. The present invention also provides an IPS or FFS display element which uses this composition.

Description

Composition and liquid crystal display device using the same

The present invention relates to a liquid crystal composition suitable for an active matrix device and an active matrix device containing the composition. In particular, the present invention relates to a liquid crystal composition having a positive dielectric anisotropy and devices containing the same, such as an IPS mode, an FFS mode, an ECB mode, a TN mode, an OCB mode, and a PSA mode.

Liquid crystal display elements are used for various measuring instruments, such as watches and calculators, panels for automobiles, printers, computers, televisions, watches, advertising boards, and the like. Typical classifications based on the display method are TN (twisted nematic) type, STN (super twisted nematic) type, VA (vertical ｇalignment) type using TFT, PSA (polymer sustained alignment) type, and IP as horizontal alignment mode. (In-plane switching) type, FFS (fringe field switching) type and the like. The liquid crystal compositions used in these liquid crystal display devices are stable against external stimuli such as moisture, air, heat, and light. And it can be driven at a low voltage.

A liquid crystal composition having a negative dielectric anisotropy (Δε) is mainly used for VA-type and PSA-type displays, and a liquid crystal composition having a positive Δε is mainly used for TN-type, STN-type, IPS-type and FFS-type displays. Is used. These liquid crystal compositions are composed of several to several tens of compounds in order to optimize Δε and refractive index anisotropy (Δn) for each display element. In order to achieve high-speed response, low operating voltage, wide operating temperature range, and high reliability as a device, the liquid crystal composition has a low viscosity (η) while maintaining the absolute value of Δε, the Δn, and the like at optimal values. It must have a high nematic phase-isotropic liquid phase transition temperature (T _NI ), excellent storage stability that does not cause precipitation or phase change at low temperatures, and is resistant to heat, light, moisture, etc. Must also be stable. Further, the IPS type or FFS type of the horizontal alignment type display has a problem that the contrast is inferior to the VA type or the PSA type display in principle, and there is a continuous demand for improvement of the contrast. Since the contrast is represented by the ratio of the ON luminance (maximum transmittance) of the display and the OFF luminance (luminance of black display), in the FFS type and IPS type displays, the characteristics as a liquid crystal composition conventionally required are not satisfied. In addition, there is a demand for a liquid crystal composition capable of realizing high transmittance and / or reduced black luminance when used as a display element.

The OFF luminance (luminance of black display) in an FFS type or IPS type display mainly depends on the element configuration, but is also affected by the physical properties of the liquid crystal composition, and is generally a liquid crystal having a small Δn and a high elastic constant. It is known that the composition is effective in reducing OFF luminance. However, when a liquid crystal composition having an excessively small Δn is used, a thick cell gap is required to keep the product of the cell gap (d) constant, and the response speed is deteriorated. On the other hand, when a liquid crystal composition having a high elastic constant is used, the response speed of the return is increased, and the thickness gap is not required.

It is known that the transmittance of an FFS type or IPS type display can be improved by changing the ratio of two component values (ε // and ε⊥) constituting the dielectric anisotropy of the liquid crystal composition. . In particular, in the case of an FFS type display element using a dielectrically positive liquid crystal composition, the liquid crystal molecules immediately above tilt up due to an electric field in a substantially vertical direction generated on a pixel electrode, so that the transmittance is reduced. There is. As a method for solving this, a method using a dielectrically negative liquid crystal composition, a method using a dielectrically positive liquid crystal composition having a relatively large ε⊥ value, and the like have been proposed. However, when a liquid crystal composition having a negative dielectric constant is used, in addition to the disadvantage that the viscosity of the liquid crystal composition is large, the response speed is reduced, and in addition, there is a problem that a displayed image is generally easily burned. are doing. In the latter, various liquid crystal compositions have been developed in recent years, but the physical and chemical properties of the liquid crystal composition are in a trade-off relationship, and it is still difficult to obtain a composition satisfying all of them. . Especially, in the FFS mode, an unexpected image sticking phenomenon is likely to occur after a short or long time pattern display due to the electric capacity of the TFT substrate itself or an asymmetric electric field, which is solved from the viewpoint of increasing the reliability of the display. Is desired.
That is, the absolute value of Δε, Δn, etc. can be adjusted to optimal values, η is small, has high T _NI , has excellent storage stability in which precipitation and phase change do not occur at low temperatures, and has heat and heat. It is stable against stimuli such as light and moisture, has a high elastic constant, exhibits high contrast when used as an IPS type or FFS type liquid crystal display device, and can suppress the occurrence of image sticking. There are continuously strong demands for specific liquid crystal compositions.

As a liquid crystal composition intended for a lateral electric field type liquid crystal display such as an IPS type or an FFS type, for example, a liquid crystal composition using a dielectrically neutral alkenyl compound represented by the formula (1) or (2) includes It is disclosed (Patent Documents 1 to 3).

(Alkenyl is an alkenyl group, and R is an alkyl group, an alkoxy group, an alkenyl group, an alkenyloxy group, an alkoxyalkyl group, and the like.)
However, these inventions have not sufficiently responded to the current demands for sophistication, and there has been a demand for the development of a liquid crystal composition that can simultaneously solve the above-mentioned problems.

Table 2004-529214 JP 2009-191264A JP 2006-328399A

The problem to be solved by the present invention is a composition having a positive Δε, a liquid crystal phase in a wide temperature range, a small η, good storage stability without causing precipitation or phase change at low temperatures, It is an object of the present invention to provide a liquid crystal composition which has a high specific resistance and a high voltage holding ratio (VHR), is stable against heat and light, and has a high elastic constant and a relatively high ε⊥. It is another object of the present invention to provide an FFS-type or IPS-type liquid crystal display device which is excellent in high-speed response, has a wide operating temperature range, suppresses image sticking, and has excellent contrast.

The present inventors have studied various liquid crystal compounds and various chemical substances, and found that the above-mentioned problems can be solved by combining specific liquid crystal compounds, and have completed the present invention.

That is, the present invention provides a component (A) composed of a compound having a positive dielectric anisotropy, a component (B) composed of a compound having a negative dielectric anisotropy, and a component composed of a dielectrically neutral compound. A composition containing (C), as component (A), at least one compound selected from the group represented by general formula (A1), and as component (B), general formula (B1) And at least one compound selected from the group represented by the general formula (C1) as the component (C), and the composition as a whole has a positive dielectric constant. It is an object to provide a liquid crystal composition having a characteristic anisotropy. It is another object of the present invention to provide an IPS type or FFS type display element using the composition.

(Wherein, R 1 ^~ R ⁵ represents an alkenyl group of an alkyl group, an alkoxy group or a 2 to 5 carbon atoms of 1 to 5 carbon atoms of 1 to 5 carbon atoms independently of one another, Y ¹ ~ Y ¹² independently represents H or F but at least two are F, Y ¹³ and Y ¹⁴ independently represent F or Cl, and X ¹ represents F, Cl, CN, CF ₃ Or OCF ₃ , m represents 0 or 1, n represents 1, 2 or 3, Z represents —C ₂ H ₄ —, —C≡C—, —COO—, —CH ＝ CH—, — CF = CF— or a single bond, and rings A and B are each independently a 1,4-cyclohexylene group, a 1,4-phenylene group, a 2-fluoro-1,4phenylene group or a 3-fluoro- Represents a 1,4-phenylene group, and when n is 2 or 3, even if a plurality of A and Z are the same, There may be.)

The liquid crystal composition of the present invention has a wide liquid crystal temperature range, low viscosity, good storage stability without causing precipitation or phase change at low temperatures, and extremely small changes in specific resistance to heat and light and voltage holding ratio. , The practicality of the product is high. In addition, a liquid crystal display device using the composition has a wide operating temperature range, high-speed response, excellent reliability, and good storage stability. In particular, when used in an FFS type or IPS type display element, the transmittance is high and the black luminance is reduced, so that a high contrast is exhibited. Further, the occurrence of image sticking can be suppressed, which is very useful.

The present invention
It contains a component (A) composed of a compound having a positive dielectric anisotropy, a component (B) composed of a compound having a negative dielectric anisotropy, and a component (C) composed of a dielectrically neutral compound. A composition,
As the component (A), at least one compound selected from the group represented by the general formula (A1) is contained,
As the component (B), at least one compound selected from the group represented by the general formula (B1) is contained,
A liquid crystal composition comprising, as the component (C), at least one compound selected from the group represented by the general formula (C1), and the composition as a whole having a positive dielectric anisotropy. And a liquid crystal display device using the same.

In the present specification, a compound having a positive dielectric anisotropy refers to a compound having a value of Δε larger than 1.5, and a compound having a negative dielectric anisotropy has a value of −1.5. A smaller compound refers to a compound which is dielectrically neutral and has a value of Δε of −1.5 or more and 1.5 or less.

The composition of the present invention contains, as the dielectrically positive component (A), a compound selected from the group represented by the general formula (A1), but the compound represented by the general formula (A1) is one kind. May be used, or two or more kinds may be used in combination.

(Wherein, R ¹ represents an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms or an alkenyl group having 2 to 5 carbon atoms, and Y ¹ to Y ¹² are each independently Represents H or F, but at least two are F and X ¹ represents F, Cl, CN, CF ₃ or OCF ₃ )
The compound represented by the general formula (A1) increases the positive dielectric anisotropy of the liquid crystal composition, appropriately adjusts the refractive index anisotropy, increases compatibility (low-temperature stability), and further increases the composition. It can also be used for the purpose of relatively increasing the value of ε⊥ of the product, and preferred compounds are given by compounds represented by the following general formulas (A1-1) to (A1-7).

(In the formula, R ¹ has the same meaning as R ¹ in formula (A1).)
The preferred content of the compound represented by the general formula (A1) in the composition is, as a lower limit, 2% by mass, 4% by mass, 6% by mass, 8% by mass, and an upper limit. Are 30% by mass, 26% by mass, 22% by mass, 18% by mass, and 14% by mass.

The composition of the present invention contains a compound represented by the general formula (B1) as a dielectrically negative component (B). Or two or more of them may be used in combination.

(Wherein R ² and R ³ independently represent an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms or an alkenyl group having 2 to 5 carbon atoms, and Y ¹³ and Y ¹⁴ independently represents F or Cl, and m represents 0 or 1.)
The compound represented by the general formula (B1) is used not only for the purpose of increasing ε⊥ of the liquid crystal composition, but also for imparting high reliability, a wide nematic temperature range, low viscosity and a high elastic constant. Preferred compounds are given by compounds represented by the following formulas (B1-1) to (B1-4).

(Wherein, R ³ has the same meaning as R ³ in formula (B1), Alkyl represents a linear alkyl group having 1 to 5 carbon atoms, and Alkenyl represents a linear alkyl group having 2 to 5 carbon atoms. Alkenyl group.)
The preferable content of the compound of the general formula (B1) in the composition is 2% by mass, 4% by mass, 5% by mass, 7% by mass, 8% by mass as a lower limit, The upper limit is 25% by mass, 20% by mass, 18% by mass, 16% by mass, 15% by mass, 14% by mass, 12% by mass, and 10% by mass. is there.

組成 The composition of the present invention contains, as the dielectrically neutral component (C), a dielectrically neutral compound selected from the group represented by the general formula (C1). The compound represented by the general formula (C1) may be used singly or in combination of two or more.

(Wherein R ⁴ and R ⁵ independently represent an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms or an alkenyl group having 2 to 5 carbon atoms, and n is 1 , 2 or 3, Z represents —C ₂ H ₄ —, —C≡C—, —COO—, —CH ＝ CH—, —CF ＝ CF— or a single bond, and rings A and B Independently represents a 1,4-cyclohexylene group, a 1,4-phenylene group, a 2-fluoro-1,4-phenylene group or a 3-fluoro-1,4-phenylene group, wherein n is 2 or 3 , A plurality of A and Z may be the same or different.)
Preferred compounds represented by the general formula (C1) are given by compounds represented by the following formulas (C1-1) to (C1-11).

(In the formula, R ⁴ and R ⁵ independently represent an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or an alkenyl group having 2 to 5 carbon atoms.)
The preferable content of the compound of the general formula (C1) is, as a lower limit, 10% by mass, 14% by mass, 18% by mass, 22% by mass, 25% by mass, and 28% by mass. , 30% by mass, and as an upper limit, 90% by mass, 85% by mass, 80% by mass, 75% by mass, 70% by mass, 66% by mass, 63% % By mass, 60% by mass, 57% by mass, and 55% by mass.

The composition of the present invention optionally contains, as a component (A) having a positive dielectric anisotropy, a compound represented by the following general formula (M) in addition to the compound represented by the general formula (A1). can do. As the compound represented by the general formula (M), one type may be used, or two or more types may be used in combination.

(Wherein, ^RM is a linear alkyl group having 1 to 5 carbon atoms, a cyclic alkyl group having 3 to 5 carbon atoms, a linear alkoxy group having 1 to 5 carbon atoms, or 2 to 5 carbon atoms. And n ^M represents 1, 2 or 3,
G ^M is (a) 1,4-cyclohexylene group (this is present in the group one -CH ₂ - or nonadjacent two or more -CH ₂ - is replaced by -O- or -S- And (b) a 1,4-phenylene group (one -CH = or two or more non-adjacent -CH = present in the group may be replaced by -N = Good.)
A hydrogen atom on the group (a) and the group (b) may be each independently substituted with a cyano group, a fluorine atom or a chlorine atom;
Z ^M represents —CH ₂ CH ₂ —, —CF ₂ O—, —COO—, —C≡C— or a single bond;
When a plurality of G ^M and Z ^M are present, they may be the same or different,
Y ^M1 and Y ^M2 independently represent a fluorine atom or a hydrogen atom,
^XM represents a fluorine atom, a chlorine atom, a trifluoromethyl group, a trifluoromethoxy group or a cyano group. However, the compound represented by the general formula (A1) is excluded. )
Preferred compounds represented by the general formula (M) are given by compounds represented by the following general formulas (M1) to (M16).

(Wherein, ^{R M} represents the same meaning as ^{R M} in the general formula (M).)
Any of the compounds represented by formulas (M1) to (M16) can be used for the purpose of lowering the driving voltage of a liquid crystal display device. The preferable content of the compound of the general formula (M) is 2% by mass as a lower limit, 4% by mass, 6% by mass, 8% by mass, and 40% by mass as an upper limit. , 35% by mass, 30% by mass, 26% by mass, 22% by mass, 18% by mass and 14% by mass.

The total content of the compound represented by the general formula (A1) and the compound represented by the general formula (M) in the composition (that is, the content of the component (A) in the composition) is as follows: The lower limit is preferably 2% by mass, 4% by mass, 6% by mass, and 8% by mass, and preferably the upper limit is 30% by mass, 26% by mass, and 22% by mass. %, 18% by mass, and 14% by mass.

The composition of the present invention optionally contains, as a component (B) having negative dielectric anisotropy, a compound represented by the following general formula (K) in addition to the compound represented by the general formula (B1). can do. One of the compounds represented by the general formula (K) may be used, or two or more of them may be used in combination.

(Wherein, R ^K1 and R ^K2 each independently represent a linear alkyl group having 1 to 5 carbon atoms, a cyclic alkyl group having 3 to 5 carbon atoms, a linear alkoxy group having 1 to 5 carbon atoms) N ^K1 and n ^K2 independently represent 0, 1 or 2; n ^K1 + n ^K2 is 1 or 2; and Y ^K1 represents a linear alkenyl group having 2 to 5 carbon atoms. And Y ^K2 independently represent a fluorine atom or a chlorine atom, and G ^K1 and G ^K2 independently represent

Represents When n ^K1 and n ^K2 are 2, the plurality of G ^K1 and G ^K2 may be the same or different. )
Preferred compounds represented by the general formula (K) are given by compounds represented by the following general formulas (K1) to (K6).

(In the formula, R ^K1 and R ^K2 represent the same meaning as R ^K1 and R ^K2 in the general formula (K).)
Any of the compounds represented by formulas (K1) to (K6) can be used for the purpose of increasing the transmittance of a liquid crystal display device. The preferred content of the compound of the general formula (K) is 3% by mass as a lower limit, 4% by mass, 6% by mass, 8% by mass, and 20% by mass as an upper limit. , 17% by mass, 15% by mass, 13% by mass, and 10% by mass.

The total content of the compound represented by the general formula (B1) and the compound represented by the general formula (K) in the composition (that is, the content of the component (B) in the composition) is as follows: The lower limit is preferably 2% by mass, 4% by mass, 6% by mass, and 8% by mass, and preferably the upper limit is 30% by mass, 26% by mass, and 22% by mass. %, 18% by mass, and 14% by mass.

The lower limit value of the preferable total content of the compounds represented by the general formulas (A1), (B1), (C1), (M) and (K) with respect to the total amount of the composition of the present invention is 80%. , 85%, 88%, 90%, 92%, 93%, 94%, 95%, 96%, 97%, 98% , 99% and 100%. The upper limit of the preferred content is 100%, 99%, 98%, and 95%.

組成 The composition of the present invention preferably does not contain a compound having a structure in which oxygen atoms are bonded to each other, such as a peracid (—CO—OO—) structure in the molecule.

When importance is placed on the reliability and long-term stability of the composition, the content of the compound having a carbonyl group is preferably 5% or less, more preferably 3% or less based on the total mass of the composition. It is more preferably set to 1% or less, and most preferably substantially not contained.

When importance is placed on the stability due to UV irradiation, the content of the compound substituted with a chlorine atom is preferably 15% or less, more preferably 10% or less, based on the total mass of the composition. %, Preferably 5% or less, more preferably 3% or less, even more preferably substantially not contained.

It is preferable to increase the content of the compound in which all the ring structures in the molecule are 6-membered rings, and the content of the compound in which the ring structure in the molecule is all 6-membered rings is 80 to the total mass of the composition. % Or more, more preferably 90% or more, and even more preferably 95% or more, and the composition is composed of only a compound having substantially all six-membered ring structures in the molecule. Is most preferred.

In order to suppress deterioration due to oxidation of the composition, it is preferable to reduce the content of the compound having a cyclohexenylene group as a ring structure, and the content of the compound having a cyclohexenylene group is determined based on the total mass of the composition. On the other hand, it is preferably at most 10%, more preferably at most 8%, more preferably at most 5%, more preferably at most 3%, even more preferably substantially free of.

When emphasis is placed on improving the viscosity and the _TNI , reduce the content of a compound having a 2-methylbenzene-1,4-diyl group in which a hydrogen atom may be substituted with a halogen in the molecule. The content of the compound having a 2-methylbenzene-1,4-diyl group in the molecule is preferably 10% or less, and more preferably 8% or less based on the total mass of the composition. The content is preferably set to 5% or less, more preferably 3% or less, and further preferably substantially not contained.

において Substantially not contained in the present application means that it is not contained except for those that are unintentionally contained.

組成 The composition of the present invention can further contain a compound having a terminal group represented by the general formula (Q) and / or the general formula (R). These compounds can improve the compatibility of the liquid crystal composition, the stability against heat and light, and the reliability typified by the image sticking phenomenon when used as a display element, by appropriately selecting the structure. .

(The wavy line in the formula means a bond)

(In the formula, R represents H, O. or an alkyl group or an alkoxy group having 1 to 5 carbon atoms, and a wavy line means a bond.)
Specifically, the compound having a terminal group represented by the general formula (Q) is preferably a compound represented by the following general formulas (Qa) to (Qe).

In the formula, R ^Q1 represents a linear alkyl group or a branched alkyl group having 1 to 10 carbon atoms, and R ^Q2 represents a linear alkyl group or a branched alkyl group having 1 to 20 carbon atoms. , R ^Q3 represents a linear alkyl group having 1 to 8 carbon atoms, a branched alkyl group, a linear alkoxy group or a branched alkoxy group, and R ^Q4 represents a linear alkyl group having 1 to 16 carbon atoms. an alkylene group or branched alkylene group, one -CH 2 in the alkylene group _- or nonadjacent two or more -CH 2 _- may be substituted by -O-, L ^Q represents a linear alkylene group or a branched alkylene group having 1 to 8 carbon atoms, W ¹ and W ² represent —CH ₂ — or an O atom, and are exclusively —CH ₂ — Alternatively, it is preferably exclusively an O atom. Among the compounds represented by the general formulas (Qa) to (Qe), the compounds represented by the general formulas (Qa), (Qc) and (Qe) further include: preferable. Among them, when the compound represented by the general formula (Qe) is used, the liquid crystal composition containing the general formulas (A1), (B1) and (C1) at the same time has excellent low-temperature stability. It is particularly preferable in that it exhibits a synergistic effect in terms of reliability and reliability.

において The composition of the present invention preferably contains one compound represented by the general formula (Q), but may contain two or more compounds. The content is preferably 0.001% to 1%, more preferably 0.001% to 0.1%, and particularly preferably 0.001% to 0.08%.

As the compound having a terminal group represented by the general formula (R), for example, a commercially available compound such as (Tinuvin 770, BASF) can be diverted or described in paragraphs [0036] to [0037] of WO 17/154590. The compounds described above that can be suitably used for the liquid crystal composition can also be used.

において In the composition of the present invention, the compound having a terminal group represented by the general formula (R) preferably contains one kind, more preferably one to three kinds. The content is preferably 0.001% to 0.5%, more preferably 0.001% to 0.2%, and particularly preferably 0.001% to 0.1%.

組成 The composition of the present invention may further contain an ultraviolet absorber. Usable ultraviolet absorbers are not particularly limited, but commercially available ultraviolet absorbers such as benzophenone-based, benzotriazole-based, cyanoacrylate-based, and triazine-based can also be used. It is preferable that one ultraviolet absorber is contained, but two or more ultraviolet absorbers may be contained. The content is preferably from 0.001% to 1%, more preferably from 0.001% to 0.1%, and particularly preferably from 0.001% to 0.05%.

T _NI of the liquid crystal composition of the present invention is preferably 70 ° C. or higher, more preferably 75 ° C. or higher, and particularly preferably 80 ° C. or higher.

The Δn of the liquid crystal composition of the present invention can be appropriately selected according to the optical design of the display, but is preferably in the range of 0.07 to 0.16, and more preferably 0.08 to 0.14. More preferably, it is particularly preferably in the range of 0.09 to 0.12.

{The preferred mode of the dielectric anisotropy of the liquid crystal composition of the present invention can be specified by the ratio of Δε to ε⊥. The value of ε⊥ / Δε is preferably 0.8 or more, more preferably 1.0 or more, still more preferably 1.3 or more, and particularly preferably 1.5 or more.

組成 The composition of the present invention can contain a polymerizable compound in order to produce a polymer-stabilized liquid crystal display device. Examples of the polymerizable compound that can be used include a photopolymerizable monomer that undergoes polymerization by energy rays such as light, and have a liquid crystal skeleton in which a plurality of six-membered rings such as biphenyl derivatives and terphenyl derivatives are connected. And polymerizable compounds. More specifically, the general formula (XX)

(Wherein X ²⁰¹ and X ²⁰² each independently represent a hydrogen atom or a methyl group;
Sp ²⁰¹ and Sp ²⁰² are each independently a single bond, an alkylene group having 1 to 8 carbon atoms or —O— (CH ₂ ) _s — (wherein _s represents an integer of 2 to 7, and an oxygen atom is Is preferably bonded to an aromatic ring).
Z ²⁰¹ represents —OCH ₂ —, —CH ₂ O—, —COO—, —OCO—, —CF ₂ O—, —OCF ₂ —, —CH ₂ CH ₂ —, —CF ₂ CF ₂ —, —CH = CH-COO-, -CH = CH-OCO-, -COO-CH = CH-, -OCO-CH = CH-, -COO-CH ₂ CH _2- , -OCO-CH ₂ CH _2- , -CH ₂ CH ₂ —COO—, —CH ₂ CH ₂ —OCO—, —COO—CH ₂ —, —OCO—CH ₂ —, —CH ₂ —COO—, —CH ₂ —OCO—, —CY ¹ = CY ² — (Wherein Y ¹ and Y ² each independently represent a fluorine atom or a hydrogen atom), —C≡C— or a single bond;
M ²⁰¹ represents a 1,4-phenylene group, a trans-1,4-cyclohexylene group or a single bond, and all 1,4-phenylene groups in the formula have any hydrogen atom represented by a fluorine atom or one carbon atom. It may be substituted by up to 5 alkyl groups or alkoxy groups. )) Are preferred.

Each of X ²⁰¹ and X ²⁰² is preferably a diacrylate derivative each representing a hydrogen atom, or both a dimethacrylate derivative having a methyl group, and a compound wherein one represents a hydrogen atom and the other represents a methyl group is also preferred. The polymerization rate of these compounds is the fastest for the diacrylate derivative, the slowest for the dimethacrylate derivative, and the middle for the asymmetric compound, and a preferred embodiment can be used depending on the application. In PSA display elements, dimethacrylate derivatives are particularly preferred.

Sp ²⁰¹ and Sp ²⁰² each independently represent a single bond, an alkylene group having 1 to 8 carbon atoms, or —O— (CH ₂ ) _s —. In a PSA display element, at least one of them is a single bond. Preferred are compounds in which both represent a single bond or one represents a single bond and the other represents an alkylene group having 1 to 8 carbon atoms or —O— (CH ₂ ) _s —. In this case, an alkyl group having 1 to 4 carbon atoms is preferable, and s is preferably 1 to 4.

Z ²⁰¹ represents —OCH ₂ —, —CH ₂ O—, —COO—, —OCO—, —CF ₂ O—, —OCF ₂ —, —CH ₂ CH ₂ —, —CF ₂ CF ₂ — or a single bond. Is preferable, -COO-, -OCO- or a single bond is more preferable, and a single bond is particularly preferable.

M ²⁰¹ represents a hydrogen atom, a fluorine atom, or a 1,4-phenylene group, a trans-1,4-cyclohexylene group or a single bond which may be substituted by an alkyl group or an alkoxy group having 1 to 5 carbon atoms. However, an optionally substituted 1,4-phenylene group or a single bond is preferable. When M ²⁰¹ represents a ring structure other than a single bond, Z ²⁰¹ is also preferably a linking group other than a single bond, and when M ²⁰¹ is a single bond, Z ²⁰¹ is preferably a single bond.

From these points, in the general formula (XX), the ring structure between Sp ²⁰¹ and Sp ²⁰² is specifically preferably the following structure.

In formula (XX), when M ²⁰¹ represents a single bond and the ring structure is formed of two rings, the ring structure between Sp ²⁰¹ and Sp ²⁰² is represented by the following formula (XXa-1) to formula (XXa-1). XXa-5), more preferably formulas (XXa-1) to (XXa-3), and particularly preferably formula (XXa-1).

(In the formula, both ends are bonded to Sp ²⁰¹ or Sp ^202. )
The polymerizable compound containing such a skeleton has an alignment regulating force after polymerization that is optimal for a PSA-type liquid crystal display element, and a good alignment state is obtained, so that display unevenness is suppressed or does not occur at all.

From the above, as the polymerizable monomer, general formulas (XX-1) to (XX-4) are particularly preferable, and among them, general formula (XX-2) is most preferable.

(In the formula, benzene may be substituted by a fluorine atom, and SP ²⁰ represents an alkylene group having 2 to 5 carbon atoms.)
When a monomer is added to the composition of the present invention, the polymerization proceeds even in the absence of a polymerization initiator, but the composition may contain a polymerization initiator to promote the polymerization. Examples of the polymerization initiator include benzoin ethers, benzophenones, acetophenones, benzyl ketals, acylphosphine oxides, and the like.

The composition containing the polymerizable compound of the present invention is provided with a liquid crystal alignment ability by polymerizing the polymerizable compound contained therein by irradiation with ultraviolet light, and controls the amount of transmitted light using the birefringence of the composition. Used in liquid crystal display devices. As liquid crystal display devices, AM-LCD (active matrix liquid crystal display device), TN (nematic liquid crystal display device), STN-LCD (super twisted nematic liquid crystal display device), OCB-LCD and IPS-LCD (in-plane switching liquid crystal display device) ), But particularly useful for AM-LCDs, and can be used for transmissive or reflective liquid crystal display devices.

(4) The liquid crystal display device using the composition of the present invention is excellent in high-speed response and reliability, is useful in realizing a wide operating temperature range, and can be suitably used for a liquid crystal display device for driving an active matrix. In addition, when used for an FFS or IPS display device, it can realize excellent contrast due to high transmittance and reduced black luminance, and thus is particularly suitable as a liquid crystal composition for IPS and FFS display devices.

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. Further, “%” in the compositions of the following Examples and Comparative Examples means “% by mass”.

特性 The characteristics measured in the examples are as follows.

T _NI : transition temperature from nematic phase to isotropic phase (° C)
T _-N : transition temperature from the smectic phase (or solid layer) to the nematic phase (° C)
[Delta] n: 25 refractive index anisotropy n at ° C. _o: using ordinary refractive index Abbe refractometer at 25 ° C., the refractive index was measured for the 589nm light source.

Δε: dielectric anisotropy at 25 ° C., 1 kHz ε⊥: vertical dielectric constant at 25 ° C., 1 kHz The cell was sealed, an AC electric field of 1 KHz was applied, and the capacitance was measured to obtain ｌll and ⊥⊥, and Δε was determined from the difference.

η: Bulk viscosity at 20 ° C. (mPa · s)
γ ₁ : rotational viscosity coefficient at 25 ° C. (mPa · s)
Vth: A liquid crystal was sealed in a TN cell having a thickness of 6 μm, and a voltage at which the transmittance changed 10% under a crossed Nicol polarizing plate was measured at 25 ° C.

K ₁₁ , K ₃₃ : A liquid crystal is sealed in a homogeneous alignment cell having a thickness of 30 μm, a voltage (V) of 1 KHz is applied from 0 to 30 V, and a change in capacitance (C) at 25 ° C. is measured. from C-V curve fitting was sought _{K 11} and _{K 33.}

K ₂₂ : A change in electric capacity (C) at 25 ° C. obtained by applying a voltage (V) of 1 KHz from 0 to 30 V to a TN cell having a thickness of 20 μm and measuring a CV curve obtained. from the threshold voltage (Vc), it was determined _{K 22} according to the following equation.
K ₂₂ = [K ₃₃ -4 [(Vc / π) ² × ε ₀・ Δε-K ₁₁ ]] / 2
(In the formula, Vc represents a threshold voltage (V) in the TN cell, Π represents a pi, and ε0 represents a dielectric constant of a vacuum.)
Transmittance (T): FFS cell enclosing a liquid crystal composition (cell gap: 3.5 μm, electrode width: 3 μm, distance between electrodes: 4 μm, SiN _x insulating layer thickness: 4000 °, alignment film inclined at 5 ° from the electrode longitudinal direction) Rubbing treatment), a VT curve was measured at 25 ° C. when a rectangular voltage of 60 Hz was applied under a crossed Nicol polarizing plate, and the maximum transmittance was determined. As the backlight, an LED surface light source of about 5,000 candela / square mail was used.

VHR: A glass cell with an alignment film enclosing a liquid crystal composition (cell gap 3.5 micron, anti-parallel, alignment film using SE-7492 manufactured by Nissan Chemical Industries, Ltd.) was used at a frequency of 3 Hz, an applied voltage of 1 V, an applied pulse of 64 μs, Voltage holding ratio (%) measured at 60 ° C.

後 VHR after heat resistance test: The voltage holding ratio (%) when the above-mentioned liquid crystal cell was held in a thermostat at 120 ° C for 1 hour and then measured in the same manner as described above.

(4) VHR after light resistance test: The voltage holding ratio (%) when the above-mentioned liquid crystal cell was placed directly above an LED backlight of about 30,000 candela / square meter and irradiated with the LED for 100 hours.

Seizure characteristics: The initial VT curve was measured in the same manner as the transmittance (T) measurement. From the obtained curves, a voltage (V98) at which the transmittance (T) became 98% and a voltage (V23) at which the transmittance (T) became 23% were determined. Subsequently, V98 was applied at 25 ° C. for 48 hours under backlight irradiation. Then, V23 was applied to measure the post-stress transmittance (T _st ), and the ratio of transmittance (T _st / T) before and after the stress when V23 was applied was determined.

Low temperature storage (LTS): The evaluation of the storage at low temperature was performed by preparing the composition, enclosing the composition in a 3.5-μm-thick FFS cell, and then heating the composition at -30 ° C or -40 ° C. The composition was stored in a test tank, and the composition was periodically visually observed for phase change or generation of a precipitate. For example, “> 480 hr” means that no phase change and no precipitation were observed after 480 hours.
(Ring structure)

(Side chain structure and connection structure)

(Comparative Examples 1-2)
The liquid crystal composition described in Example 2 of JP-A-2009-191264 and the liquid crystal composition described in Example 33 of JP-A-2006-328399 were prepared. The reason for selecting these is that the composition is described as being suitable for use in IPS-type liquid crystal display devices. The physical property values were transcribed as they were in the literature, and ε⊥ / Δε was newly calculated. In addition, the content rate in a table represents the mass% with respect to a composition.

(Examples 1 to 4)
Hereinafter, a composition satisfying the constitutional requirements of the present application was prepared, and its effect was confirmed. In addition, the content rate in a table represents the mass% with respect to a composition.

The liquid crystal compositions described in the above table were prepared, and the physical properties thereof were measured. The composition of Example 1 had a wide liquid crystal temperature range, a large ε⊥ / Δε, an extremely small γ ₁ , and a high K _avg . Further, VHR and VHR after the heat resistance test showed almost no change and high values. When the FFS cell in which the liquid crystal composition was sealed was measured using an electro-optical property measuring device (Shintech, OPTIPRO), high transmittance and high contrast were exhibited, and the response speed was sufficiently high. Further, as a result of performing an LTS test on the cell, no occurrence of precipitation or the like was observed even after lapse of 720 hours at both -30 ° C and -40 ° C. The liquid crystal composition of Example 1 can be suitably used for an IPS type or FFS type liquid crystal display device.

液晶 Similarly, the liquid crystal compositions of Examples 2 to 4 were prepared, and the physical properties thereof were measured.

The composition of Examples 2-4 is similarly broad liquid crystal temperature range as in Example 1, a large .epsilon..perp / [Delta] [epsilon], had a very small gamma _1, high K _avg. Further, VHR and VHR after the heat resistance test showed almost no change and high values. When the FFS cell in which the liquid crystal composition was sealed was measured using an electro-optical property measuring device (Shintech, OPTIPRO), high transmittance and high contrast were exhibited, and the response speed was sufficiently high. In addition, as a result of an LTS test of the cell, no precipitation or the like was observed at -30 ° C. and -40 ° C. until the elapse of 720 hours.

(4) The measurement results of the maximum transmittance and the contrast of the FFS cells in which the liquid crystal compositions of Example 1 and Comparative Examples 1 and 2 are respectively enclosed are shown. Note that the maximum transmittance was standardized by setting the transmittance of Comparative Example 2 to 100%. The contrast was calculated as a ratio of the maximum transmittance to the transmittance when the voltage was off (black display). It was found that the liquid crystal composition of Example 1 exhibited high transmittance and high contrast.

When the transmittance and contrast of the FFS cells of the liquid crystal compositions of Examples 2 to 4 were measured in the same manner, it was confirmed that the transmittance and the contrast were significantly higher than those of Comparative Examples 1 and 2, as in Example 1. Was done.
(Examples 5 to 8)
Liquid crystal compositions were prepared by adding 500 ppm of a compound represented by the following formula (Qe-1) as a component represented by the general formula (Qe) to the compositions of Examples 1 to 4, respectively ( Examples 5 to 8). The physical properties of the obtained composition, and the transmittance and contrast in the FFS cell were equivalent to those of the liquid crystal composition before the addition of the compound of the formula (Qe-1).

Next, the results of evaluating the LTS, VHR and seizure characteristics of the compositions of Examples 1 to 8 and Comparative Examples 1 and 2 are shown in the table below.

組成 The compositions of Examples 1 to 4 showed higher VHR than those of Comparative Examples 1 and 2 after the heat resistance test and the light resistance test. In addition, the seizure characteristics are smaller than those of the comparative example, indicating that the change in the VT curve before and after the stress is small, and seizure hardly occurs. Further, the compositions of Examples 5 to 8 to which the formula (Qe-1) was added had a longer LTS retention time than Examples 1 to 4, and the heat resistance and light resistance test VHR were significantly improved. are doing. In addition, the seizure characteristic was 1.0, which indicates that the seizure phenomenon due to the stress did not occur at all.

As described above, the composition of the present invention has a liquid crystal phase in a wide temperature range, low viscosity, good solubility at low temperature, high specific resistance and voltage holding ratio, stable to heat and light. In addition, it has a high elastic constant and relatively high ε⊥ and ε⊥ / Δε, and when used as a liquid crystal display device, has excellent high-speed response and reliability, has a wide operating temperature range, and has a high transmittance. Because of its excellent contrast and contrast, it can be suitably used as a liquid crystal composition for an FFS or IPS liquid crystal display device.

Claims

It contains a component (A) composed of a compound having a positive dielectric anisotropy, a component (B) composed of a compound having a negative dielectric anisotropy, and a component (C) composed of a dielectrically neutral compound. A composition,
As the component (A), at least one compound selected from the group represented by the general formula (A1) is contained,
As the component (B), at least one compound selected from the group represented by the general formula (B1) is contained,
A liquid crystal composition comprising, as the component (C), at least one compound selected from the group represented by the general formula (C1), and the composition as a whole having a positive dielectric anisotropy.

(Wherein, R 1 ~ R 5 represents an alkenyl group of an alkyl group, an alkoxy group or a 2 to 5 carbon atoms of 1 to 5 carbon atoms of 1 to 5 carbon atoms independently of one another, Y 1 ~ Y 12 independently represents H or F but at least two are F, Y 13 and Y 14 independently represent F or Cl, and X 1 represents F, Cl, CN, CF 3 Or OCF 3 , m represents 0 or 1, n represents 1, 2 or 3, Z represents —C 2 H 4 —, —C≡C—, —COO—, —CH ＝ CH—, — CF = CF— or a single bond, and rings A and B independently of one another are 1,4-cyclohexylene, 1,4-phenylene, 2-fluoro-1,4phenylene or 3-fluoro- Represents a 1,4-phenylene group, and when n is 2 or 3, even if a plurality of A and Z are the same, There may be.)
2. The liquid crystal composition according to claim 1, wherein the compound represented by the general formula (A1) contains at least one compound represented by the following general formulas (A1-1) to (A1-7).

(In the formula, R 1 has the same meaning as R 1 in formula (A1).)
3. The compound according to claim 1, wherein the compound represented by the general formula (B1) contains one or more compounds selected from the compounds represented by the general formulas (B1-1) to (B1-4). 3. The liquid crystal composition according to item 1.

(Wherein, R 3 has the same meaning as R 3 in formula (B1), Alkyl represents a linear alkyl group having 1 to 5 carbon atoms, and Alkenyl represents a linear alkyl group having 2 to 5 carbon atoms. Alkenyl group.)
The liquid crystal composition according to any one of claims 1 to 3, further comprising at least one compound having a positive dielectric anisotropy represented by the general formula (M) as the component (A).

(Wherein, RM is a linear alkyl group having 1 to 5 carbon atoms, a cyclic alkyl group having 3 to 5 carbon atoms, a linear alkoxy group having 1 to 5 carbon atoms, or 2 to 5 carbon atoms. And n M represents 1, 2 or 3,
G M is (a) 1,4-cyclohexylene group (this is present in the group one -CH 2 - or nonadjacent two or more -CH 2 - is replaced by -O- or -S- And (b) a 1,4-phenylene group (one -CH = or two or more non-adjacent -CH = present in the group may be replaced by -N = Good.)
A hydrogen atom on the group (a) and the group (b) may be each independently substituted with a cyano group, a fluorine atom or a chlorine atom;
Z M represents —CH 2 CH 2 —, —CF 2 O—, —COO—, —C≡C— or a single bond;
When a plurality of G M and Z M are present, they may be the same or different,
Y M1 and Y M2 independently represent a fluorine atom or a hydrogen atom,
XM represents a fluorine atom, a chlorine atom, a trifluoromethyl group, a trifluoromethoxy group or a cyano group. However, the compound represented by the general formula (A1) is excluded. )
The liquid crystal composition according to any one of claims 1 to 4, further comprising, as the component (B), at least one compound having a negative dielectric anisotropy represented by the general formula (K).

(Wherein, R K1 and R K2 each independently represent a linear alkyl group having 1 to 5 carbon atoms, a cyclic alkyl group having 3 to 5 carbon atoms, a linear alkoxy group having 1 to 5 carbon atoms) N K1 and n K2 independently represent 0, 1 or 2; n K1 + n K2 is 1 or 2; and Y K1 represents a linear alkenyl group having 2 to 5 carbon atoms. And Y K2 independently represent a fluorine atom or a chlorine atom, and G K1 and G K2 independently represent

Represents When n K1 and n K2 are 2, the plurality of G K1 and G K2 may be the same or different. )
6. The compound according to claim 1, wherein the compound represented by the general formula (C1) contains at least one compound selected from the group represented by the general formulas (C1-1) to (C1-11). 3. The liquid crystal composition according to item 1.

(In the formula, R 4 and R 5 independently represent an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or an alkenyl group having 2 to 5 carbon atoms.)
7. The liquid crystal composition according to claim 6, wherein the compound represented by the general formula (C1) contains at least one compound selected from the group represented by the general formulas (C1-1) to (C1-5). .
The liquid crystal composition according to any one of claims 1 to 7 mean value of elastic constant K 11 and K 33 is not less than 12pN at 25 ° C..
ＩＰ An IPS-type or FFS-type liquid crystal display device using the liquid crystal composition according to any one of claims 1 to 8.