JPWO2020044832A1 - Composition and liquid crystal display device using it - Google Patents

Abstract

Δε is a positive composition, has a liquid crystal phase in a wide temperature range, has low viscosity, has good solubility at low temperatures, has high resistivity and voltage retention, and is stable to heat and light. Also provided is a liquid crystal composition having a high elastic constant and a relatively high ε⊥. A group represented by the general formula (B1) containing a component (A) composed of a compound having positive permittivity anisotropy containing at least one compound selected from the group represented by the general formula (A1). Contains a component (B) composed of a compound having a negative dielectric anisotropy containing at least one compound selected from, and contains at least one compound selected from the group represented by the general formula (C1). Provided is a composition containing a component (C) composed of a dielectrically neutral compound and having a positive dielectric anisotropy as a whole composition. Further, an IPS type or FFS type display element using the composition is provided. [Chemical 1]

Description

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

Liquid crystal display elements have come to be used in various measuring instruments such as clocks and calculators, automobile panels, printers, computers, televisions, clocks, advertisement display boards and the like. Typical classifications based on the display method are TN (twisted nematic) type, STN (super twisted nematic) type, VA (vertical alignment) type using TFT, PSA (polymer sustained alignment) type, and IPS as the horizontal orientation mode. There are (in-plane switching) type, FFS (fringe field switching) type and the like. The liquid crystal composition used for these liquid crystal display elements is stable to external stimuli such as moisture, air, heat, and light, and exhibits a liquid crystal phase in the widest possible temperature range centered on room temperature, and has low viscosity. It is required that it can be driven with a low voltage.

Liquid crystal compositions having a negative dielectric anisotropy (Δε) are mainly used in VA-type and PSA-type displays, and liquid crystal compositions having a positive Δε in 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 as an element, low operating voltage, wide operating temperature range, and high reliability, the liquid crystal composition has a small viscosity (η) while maintaining the absolute value of Δε and Δn at the optimum values. It must have a high nematic phase-isotropic liquid crystal phase transition temperature (T _NI ), excellent storage stability that does not cause precipitation or phase change at low temperatures, and is resistant to stimuli such as heat, light, and moisture. Must also be stable. Further, since the IPS type and FFS type of the horizontally oriented display have a problem that the contrast is inferior to that of the VA type and PSA type display in principle, there is a continuous demand for contrast improvement. Contrast is represented by the ratio of the ON brightness (maximum transmittance) and the OFF brightness (brightness of black display) of the display. Therefore, in the FFS type and IPS type displays, various characteristics as a liquid crystal composition conventionally required have been obtained. In addition, there is a demand for a liquid crystal composition capable of achieving high transmittance and / or reduced black brightness when used as a display element.

The OFF brightness (brightness of black display) in an FFS type or IPS type display is mainly affected by the element configuration, but is also affected by the physical property values of the liquid crystal composition, and generally a liquid crystal having a small Δn and a high elastic constant. It is known that the composition is effective in reducing the OFF brightness. However, if a liquid crystal composition having an excessively small Δn is used, a thick cell gap is required to keep the product with the cell gap (d) constant, which causes deterioration of the response speed, which is not preferable. On the other hand, when a liquid crystal composition having a high elastic constant is used, the return response speed is increased and it is not necessary to increase the thickness gap, which is preferable as a method for reducing black brightness.

It is known that the transmittance of FFS-type and IPS-type displays can be improved by changing the ratio of the values (ε // and ε⊥) of the two components 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, there is a problem that the transmittance is lowered because the liquid crystal molecules directly above tilt up due to the electric field in the substantially vertical direction generated on the pixel electrodes. There is. As a method for solving this, a method using a liquid crystal composition that is dielectrically negative and a method that uses a liquid crystal composition that is dielectrically positive but has a relatively large ε⊥ value have been proposed. However, when a liquid crystal composition having a negative dielectric constant is used, in addition to the disadvantage that the response speed becomes slow due to the high viscosity of the liquid crystal composition, there is a problem that the displayed image is generally easily burned. doing. In the latter case, 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 that satisfies all of them. .. Especially in FFS mode, unexpected seizure phenomenon is likely to occur after short-time or long-time pattern display due to the large electric capacity of the TFT substrate itself and asymmetric electric field, which is solved from the viewpoint of high display reliability. Is desired.
That is adjustable to an optimum value of the absolute value and Δn like of [Delta] [epsilon], eta is small, has a high T _NI, with excellent storage stability does not occur the precipitation or phase change at a low temperature, heat Ya 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 element, and can suppress the occurrence of seizure. There is a continuous strong demand for specific liquid crystal compositions.

As a liquid crystal composition oriented to a transverse 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 formulas (1) and (2) is available. It is disclosed (Patent Documents 1 to 3).

(Alkenyl is an alkenyl group, R is an alkyl group, an alkoxy group, an alkenyl group, an alkenyloxy group, an alkoxyalkyl group, etc.)
However, these inventions do not sufficiently meet the current advanced demands, and the development of a liquid crystal composition capable of simultaneously solving the above-mentioned problems is required.

Special table 2004-522214 JP 2009-191264 JP 2006-328399

The problem to be solved by the present invention is that Δε is a positive composition, it has a liquid crystal phase in a wide temperature range, η is small, it does not cause precipitation or phase change at low temperature, and it has good storage stability. It is an object of the present invention to provide a liquid crystal composition having a high specific resistance and voltage retention (VHR), being stable against heat and light, and having a high elastic constant and a relatively high ε⊥. Further, by using this, it is an object of the present invention to provide an FFS type or IPS type liquid crystal display element having excellent high-speed response, a wide operating temperature range, suppression of seizure, and excellent contrast.

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

That is, the present invention comprises 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), containing at least one compound selected from the group represented by the general formula (A1) as the component (A), and the general formula (B1) as the component (B). It contains at least one compound selected from the group represented by the above, and at least one compound selected from the group represented by the general formula (C1) is contained as the component (C), and the composition as a whole is positive dielectric. An object of the present invention is to provide a liquid crystal composition characterized by having rate anisotropy. A further object of the present invention is to provide an IPS type or FFS type display element using the composition.

(In the formula, R ^{1 to} 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 Y ¹ to 5 Y ¹² represents H or F independently of each other, 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 represents OCF _3, m represents 0 or 1, n represents 1, 2 or 3, Z is _{-C 2 H 4 -, - C≡C} -, - COO -, - CH = CH -, - CF = CF- or single bond, rings A and B are independent of each other, 1,4-cyclohexylene group, 1,4-phenylene group, 2-fluoro-1,4 phenylene group or 3-fluoro- It represents a 1,4-phenylene group, but when n is 2 or 3, the plurality of A and Z may be the same or different, respectively.)

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 very small changes in resistivity and voltage retention with respect to heat and light. , The practicality of the product is high. Further, the liquid crystal display element using the composition has a wide operating temperature range, is excellent in high-speed response and reliability, and has good storage stability. In particular, when it is used for an FFS type or IPS type display element, it is very useful because it has high transmittance and reduced black brightness, so that it can exhibit high contrast and further suppress the occurrence of seizure.

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. It ’s 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.
It is a liquid crystal composition characterized by containing at least one compound selected from the group represented by the general formula (C1) as a component (C) and having a positive dielectric anisotropy as a whole composition. Further, the present invention relates to a liquid crystal display element using this.

In the present specification, a compound having a positive dielectric anisotropy means a compound having a value of Δε greater than 1.5, and a compound having a negative dielectric anisotropy means a compound having a value of Δε of −1.5. A smaller compound, and a dielectrically neutral compound means a compound having a Δε value of −1.5 or more and 1.5 or less.

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

(In the formula, 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 independent of each other. Represents H or F, but at least two are F, and X ¹ represents F, Cl, CN, CF ₃ or OCI _3. )
The compound represented by the general formula (A1) increases the positive permittivity anisotropy of the liquid crystal composition, appropriately adjusts the refractive index anisotropy, enhances compatibility (low temperature stability), and further composes. It can also be used for the purpose of relatively increasing the value of ε⊥ of a substance, and a preferable compound is given by a 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 the general formula (A1).)
The preferable content of the compound represented by the general formula (A1) in the composition is, as the lower limit, 2% by mass, 4% by mass, 6% by mass, 8% by mass, and the upper limit. As a result, it is 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), but one compound represented by the general formula (B1) is used. Alternatively, two or more kinds may be used in combination.

(In the formula, 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 represents F or Cl independently of each other, and m represents 0 or 1).
The compound represented by the general formula (B1) is not only used for the purpose of increasing ε⊥ of the liquid crystal composition, but at the same time, it can provide high reliability, a wide nematic temperature range, low viscosity and high elastic constant. Possible and preferred compounds are given by the compounds represented by the following general formulas (B1-1) to (B1-4).

(In the formula, R ³ has the same meaning as R ³ in the general 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. Represents an alkenyl group.)
The preferable content of the compound of the general formula (B1) in the composition is, as a lower limit, 2% by mass, 4% by mass, 5% by mass, 7% by mass, and 8% by mass. 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.

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). As the compound represented by the general formula (C1), one kind may be used, or two or more kinds may be used in combination.

(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, and n is 1. It represents 2 or 3, Z is _{-C 2 H 4 -, - C≡C} -, - COO -, - CH = CH -, - CF = CF- or a single bond, rings a and B are mutually Independently, it 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, but when n is 2 or 3. , A plurality of A and Z may be the same or different.)
The preferred compound represented by the general formula (C1) is given by the 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 the upper limit is 90% by mass, 85% by mass, 80% by mass, 75% by mass, 70% by mass, 66% by mass, 63. It is 60% by mass, it is 57% by mass, and it is 55% by mass.

The composition of the present invention optionally contains, as the component (A) having 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 kind may be used, or two or more kinds may be used in combination.

(Wherein, R ^M is a linear alkyl group of 1 to 5 carbon atoms, a cyclic alkyl group having 3 to 5 carbon atoms, C2-5 straight-chain alkoxy group or a carbon atom of 1 to 5 carbon atoms Represents the linear alkenyl group of, nm ^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- (B) 1,4-phenylene group (one -CH = existing in this group or two or more -CH = not adjacent to each other may be replaced with -N =. Good.)
Represents a group selected from the group consisting of, and the hydrogen atoms on the above groups (a) and (b) may be independently substituted with cyano groups, fluorine atoms or chlorine atoms, respectively.
Z ^M represents −CH ₂ CH _2- , −CF ₂ O−, −COO−, −C≡C− or a single bond.
If G ^M and Z ^M there are a plurality may be the same or different,
Y ^M1 and Y ^M2 represent fluorine or hydrogen atoms independently of each other.
X ^M 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 preferred compound represented by the general formula (M) is given by the 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 the general formulas (M1) to (M16) can be used for the purpose of lowering the driving voltage of the liquid crystal display element. The preferable content of the compound of the general formula (M) is 2% by mass, 4% by mass, 6% by mass, 8% by mass as the lower limit value, and 40% by mass as the upper limit value. , 35% by mass, 30% by mass, 26% by mass, 22% by mass, 18% by mass, and 14% by mass.

Further, 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 determined. 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 a compound represented by the following general formula (K) in addition to the compound represented by the general formula (B1) as the component (B) having a negative dielectric anisotropy. can do. As the compound represented by the general formula (K), one kind may be used, or two or more kinds may be used in combination.

(In the formula, R ^K1 and R ^K2 are independent of each other, a linear alkyl group having 1 to 5 carbon atoms, a cyclic alkyl group having 3 to 5 carbon atoms, and a linear alkoxy having 1 to 5 carbon atoms. It represents a group or a linear alkenyl group having 2 to 5 carbon atoms, and n ^K1 and n ^K2 represent 0, 1 or 2 independently of each other, whereas n ^K1 + n ^K2 is 1 or 2 and Y ^K1. And Y ^K2 represent fluorine or chlorine atoms independently of each other, and G ^K1 and G ^K2 are independent of each other.

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

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

Further, 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 determined. 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 of the preferable content of the total 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%. It is 99% and 100%. The preferred upper limit of the content is 100%, 99%, 98% and 95%.

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 the reliability and long-term stability of the composition are emphasized, 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 preferably 1% or less, and most preferably not substantially contained.

When the stability by UV irradiation is emphasized, the content of the compound substituted with chlorine atoms is preferably 15% or less, preferably 10% or less, based on the total mass of the composition. % Or less, more preferably 5% or less, more preferably 3% or less, and even more preferably substantially no content.

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

In order to suppress deterioration of the composition due to oxidation, 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 added to the total mass of the composition. On the other hand, it is preferably 10% or less, preferably 8% or less, more preferably 5% or less, preferably 3% or less, and further preferably substantially not contained.

When the improvement of viscosity and the improvement of _TNI are emphasized, the content of the compound having a 2-methylbenzene-1,4-diyl group in which the hydrogen atom may be substituted with halogen should be reduced. The content of the compound having a 2-methylbenzene-1,4-diyl group in the molecule is preferably 10% or less, preferably 8% or less, based on the total mass of the composition. It is preferably 5% or less, more preferably 3% or less, and even more preferably substantially absent.

In the present application, substantially not contained means that it is not contained except for an unintentionally contained substance.

The composition in the present invention can further contain a compound having a terminal group represented by the general formula (Q) and / or the general formula (R). By appropriately selecting the structure of these compounds, it is possible to improve the compatibility of the liquid crystal composition, the stability against heat and light, and the reliability represented by the seizure phenomenon when used as a display element. ..

(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 the 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 (Q-e).

In the formula, ^RQ1 represents a linear alkyl group or a branched alkyl group having 1 to 10 carbon atoms, and ^RQ2 represents a linear alkyl group or a branched alkyl group having 1 to 20 carbon atoms. , ^RQ3 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 ^RQ4 is 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 chain alkylene group having 1 to 8 carbon atoms, and W ¹ and W ² represent -CH _2- or O atoms, which are exclusively -CH _2- or. Alternatively, it is preferably an O atom exclusively. Among the compounds represented by the general formulas (Qa) to (Qe), the compounds represented by the general formulas (Qa), (Qc) and the general formula (Qe) are further added. preferable. Above all, when the compound represented by the general formula (Q-e) is used, the liquid crystal composition containing the general formula (A1), the general formula (B1) and the general formula (C1) at the same time has excellent low temperature stability. It is particularly preferable because it exerts a synergistic effect in terms of reliability and reliability.

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), a commercially available compound such as (Tinuvin770, BASF) can be diverted, and paragraphs [0036] to [0037] of WO17 / 154590 can be used. The described compounds that can be suitably used for liquid crystal compositions can also be used.

In the composition of the present invention, it is preferable to contain one kind of compound having a terminal group represented by the general formula (R), and 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%.

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

The 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, preferably 0.08 to 0.14. It is more preferable, and it is particularly preferable that it is 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 and ε⊥. The value of ε⊥ / Δε is preferably 0.8 or more, more preferably 1.0 or more, even more preferably 1.3 or more, and particularly preferably 1.5 or more.

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 in which polymerization proceeds by an energy ray such as light, and as a structure, for example, it has a liquid crystal skeleton in which a plurality of six-membered rings such as a biphenyl derivative and a terphenyl derivative are linked. Polymerizable compounds and the like can be mentioned. More specifically, the general formula (XX)

(In the formula, X ²⁰¹ and X ²⁰² each independently represent a hydrogen atom or a methyl group.
Sp ²⁰¹ and Sp ²⁰² are independent, single bond, alkylene group having 1 to 8 carbon atoms or -O- (CH ₂ ) _s- (in the formula, s represents an integer of 2 to 7, and the oxygen atom is It shall be attached to the aromatic ring.) Is preferable.
Z ²⁰¹ is -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- (In the equation, Y ¹ and Y ² 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 an arbitrary hydrogen atom as a fluorine atom or 1 carbon atom. It may be substituted with an alkyl group or an alkoxy group of ~ 5. ) Is preferable.

Both X ²⁰¹ and X ²⁰² are preferably a diacrylate derivative representing a hydrogen atom and a dimethacrylate derivative having a methyl group, and a compound in which one represents a hydrogen atom and the other represents a methyl group is also preferable. As for the polymerization rate of these compounds, the diacrylate derivative is the fastest, the dimethacrylate derivative is the slowest, and the asymmetric compound is in the middle, and a preferred embodiment can be used depending on the application. Dimethacrylate derivatives are particularly preferred in PSA display devices.

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− , but at least one of them is a single bond in the PSA display element. Is preferable, and a compound that both represent a single bond or an embodiment in which one represents a single bond and the other represents an alkylene group having 1 to 8 carbon atoms or −O− (CH ₂ ) _s− is preferred. In this case, an alkyl group having 1 to 4 carbon atoms is preferable, and s is preferably 1 to 4.

Z ²⁰¹ is -OCH _2- , -CH ₂ O-, -COO-, -OCO-, -CF ₂ O-, -OCF _2- , -CH ₂ CH _2- , -CF ₂ CF _2- or single bond. Is preferable, -COO-, -OCO- or a single bond is more preferable, and a single bond is particularly preferable.

M ²⁰¹ has a 1,4-phenylene group, a trans-1,4-cyclohexylene group or a single bond in which any hydrogen atom may be substituted with a fluorine atom or an alkyl group or an alkoxy group having 1 to 5 carbon atoms. As represented, 1,4-phenylene group or single bond which may be substituted is preferable. When M ²⁰¹ represents a ring structure other than a single bond, Z ²⁰¹ is 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 preferably the structure described below.

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

(In the equation, both ends shall be coupled to Sp ²⁰¹ or Sp ^202. )
Since the polymerizable compound containing these skeletons has the optimum orientation regulating force after polymerization for the PSA type liquid crystal display element and a good orientation state can be obtained, display unevenness is suppressed or does not occur at all.

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

(In the formula, benzene may be substituted with a fluorine atom, and SP ²⁰ represents an alkylene group having 2 to 5 carbon atoms.)
When the monomer is added to the composition of the present invention, the polymerization proceeds even in the absence of the polymerization initiator, but the polymerization initiator may be contained in order 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 imparted with a liquid crystal orientation ability by polymerizing the polymerizable compound contained therein by irradiation with ultraviolet rays, and the amount of transmitted light is controlled by utilizing the birefringence of the composition. Used for liquid crystal display elements. As liquid crystal display elements, AM-LCD (active matrix liquid crystal display element), TN (nematic liquid crystal display element), STN-LCD (super twisted nematic liquid crystal display element), OCB-LCD and IPS-LCD (inplane switching liquid crystal display element) ), But it is particularly useful for AM-LCDs, and can be used for transmissive or reflective liquid crystal display elements.

The liquid crystal display element using the composition of the present invention is excellent in high-speed response and reliability, is useful for realizing a wide operating temperature range, and can be suitably used for an active matrix driving liquid crystal display element. Further, it is particularly suitable as a liquid crystal composition for IPS type and FFS type display elements because it can realize excellent contrast due to high transmittance and reduced black brightness when used for FFS type or IPS type display elements.

The present invention will be described in more detail with reference to Examples below, but the present invention is not limited to these Examples. In addition, "%" in the compositions of the following Examples and Comparative Examples means "mass%".

The characteristics measured in the examples are as follows.

T _NI : Transition temperature from nematic phase to isotropic phase (° C)
_TN : Transition temperature (° C) from smectic phase (or solid layer) to nematic phase
[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: Permittivity anisotropy at 25 ° C and 1kHz ε⊥: Permittivity in the vertical direction at 25 ° C and 1kHz Two types of cells with different orientation treatment (homeotropic orientation, homogeneous orientation, substrate thickness 10 microns) It was sealed, an AC electric field of 1 KHz was applied, the capacitance was measured, εll and ε⊥ were obtained, 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 enclosed in a TN cell having a thickness of 6 microns, and a voltage at 25 ° C. under which the transmittance changed by 10% was measured.

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

K ₂₂ : The change in the electric capacity (C) at 25 ° C. obtained by applying a voltage (V) of 1 KHz to a TN cell having a thickness of 20 microns from 0 to 30 V was measured, and the obtained CV curve From the threshold voltage (Vc), K ₂₂ was calculated according to the following formula.
K ₂₂ = [K ₃₃ -4 [(Vc / π) ² × ε ₀・ Δε-K ₁₁ ]] / 2
(In the formula, Vc represents the threshold voltage (V) in the TN cell, Π represents the pi, and ε0 represents the permittivity of the vacuum.)
Transmittance (T): FFS cell (cell gap 3.5 microns, electrode width 3 microns, distance between electrodes 4 microns, SiN _x insulating layer thickness 4000 Å, alignment film tilted 5 ° from the electrode longitudinal direction) containing the liquid crystal composition. The maximum transmittance was determined by measuring the VT curve when a rectangular voltage of 60 Hz was applied under a cross Nicol polarizing plate at 25 ° C. to the rubbing process. An LED surface light source of about 5,000 candelas / square mail was used as the backlight.

VHR: A glass cell with an alignment film containing a liquid crystal composition (cell gap 3.5 microns, antiparallel, SE-7492 manufactured by Nissan Chemical Industries, Ltd. is used for the alignment film), frequency 3 Hz, applied voltage 1 V, applied pulse 64 μs, Voltage retention rate (%) when measured under the condition of 60 ° C.

After heat resistance test VHR: Voltage retention rate (%) when the above-mentioned liquid crystal cell is held in a constant temperature bath at 120 ° C. for 1 hour and then measured in the same manner as in the above method.

After light resistance test VHR: Voltage retention rate (%) when the above-mentioned liquid crystal cell is placed directly above an LED backlight of about 30,000 candelas / square meter and the LED is irradiated for 100 hours.

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

Cryopreservation (LTS): For evaluation of shelf life at low temperature, after preparing the composition, the composition is enclosed in an FFS cell having a thickness of 3.5 microns, and this is subjected to a temperature control formula of -30 ° C or -40 ° C. It was stored in a test chamber, and the phase change of the composition or the generation of precipitates was regularly visually observed. For example, "> 480 hr" means that no phase change or precipitation was confirmed after 480 hours.
(Ring structure)

(Side chain structure and connecting 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 it is described that the composition can be suitably used for an IPS type liquid crystal display element. As for the physical property values, the values described in the document were transcribed as they were, and ε⊥ / Δε was newly calculated. The content in the table represents mass% with respect to the composition.

(Examples 1 to 4)
The composition satisfying the constituent requirements of the present application was adjusted below, and its effect was confirmed. The content in the table represents mass% with respect to the composition.

The liquid crystal compositions shown in the above table were prepared, and their physical property values were measured. Compositions broad liquid crystal temperature range in the first embodiment, a large .epsilon..perp / [Delta] [epsilon], had a very small gamma _1, high K _avg. In addition, VHR and VHR after the heat resistance test showed almost no change and showed high values. When the FFS cell containing the liquid crystal composition was measured using an electro-optical characteristic measuring device (Syntec, OPTIPRO), it showed high transmittance and high contrast, and the response speed was sufficiently high. In addition, as a result of conducting an LTS test on the cell, no precipitation or the like was observed even after 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 element.

The liquid crystal compositions of Examples 2 to 4 were prepared in the same manner, and their physical property values were measured.

The compositions of Examples 2-4 also had a wide liquid crystal temperature range, large ε⊥ / Δε, extremely small γ ₁ , and high _Avg , similar to Example 1. In addition, VHR and VHR after the heat resistance test showed almost no change and showed high values. When the FFS cell containing the liquid crystal composition was measured using an electro-optical characteristic measuring device (Syntec, OPTIPRO), it showed high transmittance and high contrast, and the response speed was sufficiently high. In addition, as a result of conducting an LTS test on the cell, no precipitation or the like was observed until the lapse of 720 hours at both −30 ° C. and −40 ° C.

The measurement results of the maximum transmittance and the contrast of the FFS cell in which the liquid crystal compositions of Example 1 and Comparative Examples 1 and 2 are enclosed are shown. The maximum transmittance was standardized with the transmittance of Comparative Example 2 as 100%. The contrast was calculated as the ratio of the maximum transmittance to the transmittance when the voltage was off (displayed in black). The liquid crystal composition of Example 1 was found to exhibit high transmittance and high contrast.

When the transmittance and contrast of the FFS cell were measured in the same manner for the liquid crystal compositions of Examples 2 to 4, it was confirmed that they showed significantly higher transmittance and higher contrast 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 (Q-e-1) as a component represented by the general formula (Q-e) to the compositions of Examples 1 to 4 (each). Examples 5-8). The physical property values of the obtained composition and the transmittance and contrast in the FFS cell were the same as those of the liquid crystal composition before the addition of the compound of the formula (Q-e-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.

The compositions of Examples 1 to 4 showed higher VHR than Comparative Examples 1 and 2 after the heat resistance test and the light resistance test. In addition, the seizure characteristic also shows a smaller value than that of the comparative example, and it can be seen that the change in the VT curve is small before and after stress, and seizure is unlikely to occur. In addition, the compositions of Examples 5 to 8 to which the formula (Q-e-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. doing. Further, the seizure characteristic is 1.0, and it can be seen that the seizure phenomenon due to stress did not occur at all.

Based on the above, the composition of the present invention has a liquid crystal phase in a wide temperature range, has low viscosity, has good solubility at low temperatures, has high specific resistance and voltage retention, and is stable against 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 element, it has excellent high-speed response and reliability, a wide operating temperature range, and transmittance. It can be suitably used as a liquid crystal composition for an FFS type or IPS type liquid crystal display element because of its excellent contrast.

Claims (9)

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. It ’s 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 characterized by containing at least one compound selected from the group represented by the general formula (C1) as a component (C) and having a positive dielectric anisotropy as a whole composition.

(In the formula, R ^{1 to} 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 Y ¹ to 5 Y ¹² represents H or F independently of each other, 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 represents OCF _3, m represents 0 or 1, n represents 1, 2 or 3, Z is _{-C 2 H 4 -, - C≡C} -, - COO -, - CH = CH -, - CF = CF- or single bond, rings A and B are independent of each other, 1,4-cyclohexylene group, 1,4-phenylene group, 2-fluoro-1,4 phenylene group or 3-fluoro- It represents a 1,4-phenylene group, but when n is 2 or 3, the plurality of A and Z may be the same or different, respectively.) The liquid crystal composition according to claim 1, which contains at least one compound represented by the following general formulas (A1-1) to (A1-7) as the compound represented by the general formula (A1).

(In the formula, R ¹ has the same meaning as R ¹ in the general formula (A1).) Claim 1 or 2 containing one or more compounds selected from the compounds represented by the general formulas (B1-1) to (B1-4) as the compound represented by the general formula (B1). The liquid crystal composition according to.

(In the formula, R ³ has the same meaning as R ³ in the general 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. Represents an alkenyl group.) The liquid crystal composition according to any one of claims 1 to 3, further containing at least one compound having a positive dielectric anisotropy represented by the general formula (M) as the component (A).

(Wherein, R ^M is a linear alkyl group of 1 to 5 carbon atoms, a cyclic alkyl group having 3 to 5 carbon atoms, C2-5 straight-chain alkoxy group or a carbon atom of 1 to 5 carbon atoms Represents the linear alkenyl group of, nm ^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- (B) 1,4-phenylene group (one -CH = existing in this group or two or more -CH = not adjacent to each other may be replaced with -N =. Good.)
Represents a group selected from the group consisting of, and the hydrogen atoms on the above groups (a) and (b) may be independently substituted with cyano groups, fluorine atoms or chlorine atoms, respectively.
Z ^M represents −CH ₂ CH _2- , −CF ₂ O−, −COO−, −C≡C− or a single bond.
If G ^M and Z ^M there are a plurality may be the same or different,
Y ^M1 and Y ^M2 represent fluorine or hydrogen atoms independently of each other.
X ^M 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 containing at least one compound having a negative dielectric anisotropy represented by the general formula (K) as the component (B).

(In the formula, R ^K1 and R ^K2 are independent of each other, a linear alkyl group having 1 to 5 carbon atoms, a cyclic alkyl group having 3 to 5 carbon atoms, and a linear alkoxy having 1 to 5 carbon atoms. It represents a group or a linear alkenyl group having 2 to 5 carbon atoms, and n ^K1 and n ^K2 represent 0, 1 or 2 independently of each other, whereas n ^K1 + n ^K2 is 1 or 2 and Y ^K1. And Y ^K2 represent fluorine or chlorine atoms independently of each other, and G ^K1 and G ^K2 are independent of each other.

Represents. When n ^K1 and n ^K2 are 2, the plurality of G ^K1 and G ^K2 may be the same or different. ) Any one of claims 1 to 5 containing at least one compound selected from the group represented by the general formulas (C1-1) to (C1-11) as the compound represented by the general formula (C1). The liquid crystal composition according to.

(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 liquid crystal composition according to claim 6, which contains at least one compound selected from the group represented by the general formulas (C1-1) to (C1-5) as the compound represented by the general formula (C1). .. The liquid crystal composition according to any one of claims 1 to 7, wherein the average value of the elastic constants K ₁₁ and K ₃₃ at 25 ° C. is 12 pN or more. An IPS-type or FFS-type liquid crystal display element using the liquid crystal composition according to any one of claims 1 to 8.