JP2006016586A - Nematic liquid crystal composition and liquid crystal display device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal composition having moderately large resistivity without using any material that markedly decreases resistivity, and also capable of quickly relaxing the abnormal orientation of liquid crystal molecules on the application of an interim voltage caused by electric charge attributable to e.g. static electricity of a liquid crystal display device using the composition. <P>SOLUTION: The nematic liquid crystal composition contains one or more semi-polar organoboron compounds or charge transfer complexes constituted thereof and has a resistivity of 1.0×10<SP>11</SP>to 1.0×10<SP>13</SP>Ωcm. The liquid crystal display device using this composition is also provided. This nematic liquid crystal composition has a moderately high resistivity and is characteristic in quickly relaxing the abnormal orientation of liquid crystal molecules on the application of an interim voltage caused by electric charge attributable to e.g. static electricity, therefore enabling liquid crystal display devices to be efficiently produced through cutting the time of discharging electric charge caused by electrification in their production process. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a nematic liquid crystal composition having improved behavior due to application of a temporary voltage resulting from charging due to static electricity or the like, and a liquid crystal display device using the same.

  In the manufacturing process of liquid crystal display elements such as twisted nematic, super twisted nematic or active matrix, when the protective film affixed to the surface of the liquid crystal display element is peeled off, an electric field (peeling charge) due to static electricity is generated in the element. . This electric field often aligns the liquid crystal composition in the non-lighted portion, i.e., is in a lit state, and the aligned state continues until the electric field is discharged. The time required for this electric field to discharge is not negligible, and the work must be interrupted not only in the manufacturing process but also in the inspection process or the shipping process such as wiping off the dirt on the element surface. (Production time per product) will be worsened.

It has been disclosed that the problem of abnormal alignment due to charging can be alleviated by reducing the specific resistance value of the liquid crystal composition (see Patent Document 1). A liquid crystal composition with a low specific resistance value has a low specific resistance even when a temporary voltage is applied due to charging due to static electricity, etc., so that charges are quickly discharged and the liquid crystal molecules are aligned when no voltage is applied. Can be restored. For example, the specific resistance value of a general liquid crystal composition in a nematic liquid crystal display element is often 1 × 10 ¹¹ Ωcm or more, and the relaxation time of liquid crystal molecules with respect to temporary application of voltage due to charging is considerably long. When the specific resistance is reduced to the 1 × 10 ⁹ Ωcm level by adding a substance that lowers the specific resistance to this composition, the charge is relieved very quickly, and the temporary voltage caused by the electrostatic charge is reduced. Even if applied, almost no change in the alignment state can be confirmed. However, in a liquid crystal display element using a liquid crystal composition having a specific resistance lower than 1 × 10 ¹⁰ Ωcm, the power consumption is often increased, and it may cause defective display such as image burn-in due to an electrical short circuit. is there. Accordingly, a liquid crystal composition having a reasonably large specific resistance value and improved behavior with respect to temporary voltage application caused by charging due to static electricity or the like of the liquid crystal display element, that is, temporary due to charging due to static electricity or the like Development of a liquid crystal composition in which relaxation of liquid crystal molecules is sufficiently fast with respect to application of a large voltage is demanded.

  As a method for alleviating abnormal alignment of liquid crystal molecules due to static electricity or the like in the above liquid crystal composition, for example, a method of adding an ionic substance such as cryptand is disclosed (see Patent Document 2). However, the ionic component in the liquid crystal composition is adsorbed by a polymer film such as polyimide in the liquid crystal display element in a part of the injection port or the like, which often causes display unevenness. .

  Similarly, as a method for relieving abnormal alignment of liquid crystal molecules due to static electricity or the like, a method of adding a nonionic surfactant such as ethylene glycol or a copolymer thereof is disclosed (Patent Document 3). However, the effect of this method is easily affected by the amount of ions in the liquid crystal and the alignment film and the alignment state due to the antistatic mechanism, and there are cases where sufficient antistatic effect cannot be obtained. When added to, the nematic-isotropic phase transition temperature (liquid crystal phase upper limit temperature) of the liquid crystal composition, which is one of the items showing the reliability of the liquid crystal display element, is greatly reduced as the addition ratio increases. Had.

  Alternatively, a method of adding a so-called crown ether such as a cyclic polyether has been disclosed as a method for relaxing abnormal alignment of liquid crystal molecules due to static electricity or the like (Patent Document 4). However, crown ethers have a strong toxicity such as giving significant irritation to human skin or eyes, and have a problem that there is a risk of causing a danger in a working environment in manufacturing a liquid crystal display element.

  Furthermore, when the conventional non-liquid crystal compounds as described above are added, there are problems such as a decrease in compatibility with other liquid crystal compounds and a deterioration in liquid crystal properties. In addition, no additive has been found that can quickly relax the abnormal alignment of liquid crystal molecules with respect to the application of a temporary voltage caused by charging due to static electricity or the like without lowering the specific resistance value and display quality. .

JP 59-4676 (2 pages) JP-A-4-28788 (page 2) JP-A-4-180993 (page 4) Japanese National Patent Publication No. 11-508286 (2 pages)

  An object of the present invention is to provide a temporary voltage that has a reasonably large specific resistance value and is caused by charging of the liquid crystal display element due to static electricity or the like without using a material that significantly reduces the specific resistance and the liquid crystal phase upper limit temperature. It is to provide a liquid crystal composition capable of quickly relaxing abnormal alignment of liquid crystal molecules with respect to application of.

  The inventor of the present application has studied a nematic liquid crystal composition containing a semipolar organoboron compound or a charge transfer complex composed of a semipolar organoboron compound. As a result, the present invention has been completed.

That is, the present invention contains one or more kinds of semipolar organic boron compounds or charge transfer complexes composed of semipolar organic boron compounds, and the number of boron atoms in one molecule of the semipolar organic boron compound is 5 or less. A nematic liquid crystal composition having a specific resistance value of 1.0 × 10 ¹⁰ Ωcm or more and 1.0 × 10 ¹³ Ωcm or less and a liquid crystal display device using the same are provided.

  The nematic liquid crystal composition of the present invention has a reasonably large specific resistance value, and has a feature of quickly relaxing abnormal alignment of liquid crystal molecules with respect to temporary voltage application caused by charging due to static electricity or the like. The discharge time of charges resulting from charging in the process is shortened, and the liquid crystal display element can be efficiently manufactured.

An example of the present invention will be described below.
In the present invention, a semipolar organoboron compound or a charge transfer complex composed of a semipolar organoboron compound is contained in the nematic liquid crystal composition by at least one kind, so that the static electricity of the liquid crystal display element can be compared with the conventional liquid crystal composition. It is possible to improve the time for relaxing the abnormal orientation of the liquid crystal molecules with respect to the application of a temporary voltage caused by charging due to.

  The semipolar organic boron compound generally represents an organic boron compound having a semipolar bond. Since boron is trivalent, boron forms a bond with three oxygen atoms when forming a boric acid derivative. However, a vacant electron orbital exists in the boron atom, and a lone electron pair such as an oxygen atom is coordinated in this orbital, so that the boron atom is stabilized with a special structure bonded to four oxygen atoms. Since this coordination bond is called a semipolar bond, an organic boron compound having a semipolar bond is generally called a semipolar boron compound. The semipolar organoboron compound (term) used in the present invention is also used in this sense.

  Examples of the semipolar organoboron compound added to the liquid crystal composition of the present invention include di (glycerin) borate, di (glycerin) borate monovalent carboxylic acid ester, di (catechol) borate, di (1,2-propylene glycol) Borate, di (2-ethyl-1,3-hexanediol) borate or general formula (I)

で表される骨格を有する化合物が好ましいが、液晶組成物との相溶性を考慮すると、一分子中に含まれるホウ素原子の数は一原子であることが好ましい。さらに具体的には一般式（I-1）又は一般式（I-2）

In view of compatibility with the liquid crystal composition, the number of boron atoms contained in one molecule is preferably one atom. More specifically, general formula (I-1) or general formula (I-2)

(Wherein R ¹ and R ² are each independently a hydrogen atom, a hydroxyl group, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, or 2 carbon atoms) 12 alkenyloxy groups, alkyl groups having 1 to 12 carbon atoms substituted by halogen, alkoxy groups having 1 to 12 carbon atoms substituted by halogen, alkenyl groups having 2 to 12 carbon atoms substituted by halogen, or halogen Represents a substituted alkenyloxy group having 2 to 12 carbon atoms, and A ¹ and A ² each independently represent a single bond, an alkylene group having 1 to 10 carbon atoms, an aryl group having 6 to 18 carbon atoms,-(- _{(CH 2) n O-) m} - (n represents an integer of 1 to 10, m represents an integer of 1 to _{30), -. CH 2 -O} -CO-R 3 -CO- (R Represents a hydrocarbon group having 60 carbon number of 1.) Or ^{_{-CH 2 -O-CO-NH-}} R 3 represents a -NH-CO-, in each p and q independently, integer from 1 to 10 In the case where a plurality of A ¹ and A ² are present, they may be the same or different from each other.

  The content of these semipolar organic boron compounds is preferably in the range of 0.00001 to 1% by mass, and more preferably in the range of 0.0001 to 0.1% by mass.

The liquid crystal composition of the present invention has a specific resistance value of 1.0 × 10 ¹⁰ Ωcm or more and 1.0 × 10 ¹³ Ωcm or less. The lower limit value is preferably 1.0 × 10 ¹¹ Ωcm or more, and the upper limit value is 1. 0 × 10 ¹² Ωcm or less is preferable, and 1.0 × 10 ¹¹ Ωcm or more and 1.0 × 10 ¹² Ωcm or less is more preferable.

  The semipolar organoboron compound described above has the property of easily becoming an electron donor, and forms a charge transfer complex in combination with an appropriate electron acceptor. The charge transfer complex composed of the semipolar organic boron compound also has an action of quickly relaxing the abnormal alignment of the liquid crystal molecules with respect to the temporary application of voltage caused by charging due to static electricity or the like.

  In order to form the charge transfer complex used in the present invention, a semipolar organoboron compound and an electron donor that are electron acceptors are required. As the electron donor, fulvalene derivatives such as tetrathiofulvalene and tetraselenofulvalene, phthalocyanine and derivatives thereof, amine compounds, hydroquinones, and the like are known, but amine compounds are preferable. Amine compounds are classified into aliphatic amine compounds and aromatic amine compounds. For example, ethylenediamine, hexamethylenediamine, dimethylaminopropylamine, phenylenediamine, methyliminobispropylamine, piperazine, polyethyleneimino, and ethylene oxide addition thereof. Products, polyvinyl pyridine, poly (dimethylaminoethyl) acrylate, poly (dimethylaminopropyl) acrylamide, diallylamine-isobutylene alternating copolymer, and the like. These may be used alone or in combination as required.

  The content of the charge transfer complex composed of these semipolar organoboron compounds is preferably in the range of 0.00001 to 1% by mass, and more preferably in the range of 0.0001 to 0.1% by mass.

  The nematic liquid crystal composition of the present invention has the general formula (II)

Wherein R ⁴ represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an alkyl group having 1 to 12 carbon atoms substituted with at least one halogen, an alkenyl group having 2 to 12 carbon atoms, or at least one halogen. Represents an alkenyl group having 2 to 12 carbon atoms substituted by the above, and one or two or more CH ₂ groups present in these groups are each independently an oxygen atom, as O atoms are not directly bonded to each other, May be replaced by a sulfur atom, -CO-, -COO-, -OCO- or -OCO-O-;
B ¹ and B ² are each independently a trans-1,4-cyclohexylene group (one CH ₂ group present in this group or _two non-adjacent CH ₂ groups are oxygen atoms or sulfur). May be substituted with an atom), 1,4-phenylene group (one or more CH groups present in this group may be substituted with a nitrogen atom), 1,4-cyclohexeni Rene group, 1,4-bicyclo [2.2.2] octylene group, piperidine-1,4-diyl group, naphthalene-2,6-diyl group, decahydronaphthalene-2,6-diyl group, or 1,2 , 3,4-tetrahydronaphthalene-2,6-diyl group, a hydrogen atom present in these groups may be substituted with a methyl group, -CN or halogen,
s and t each independently represent 0, 1 or 2, but the sum of s and t is 3 or less,
Z ¹ and Z ² independently represent —CH ₂ CH ₂ —, —CH═CH—, —CH (CH ₃ ) CH ₂ —, —CH ₂ CH (CH ₃ ) —, —CH (CH ₃ ). CH (CH ₃ ) —, —CF ₂ CF ₂ —, —CF═CF—, —CH ₂ O—, —OCH ₂ —, —OCH (CH ₃ ) —, —CH (CH ₃ ) O—, — ( CH ₂ ) ₄ —, — (CH ₂ ) ₃ O—, —O (CH ₂ ) ₃ —, —C≡C—, —CF ₂ O—, —OCF ₂ —, —COO—, —OCO—, — Represents COS-, -SCO- or a single bond,
L ¹ and L ³ each independently represent -H, -F or -Cl, and L ² represents -F, -Cl, -CN, -CF ₃ , -OCH ₂ F, -OCHF ₂ or -OCF. ₃ or —CH ₂ CF ₃ , and when there are a plurality of B ¹ , B ² , Z ¹ and Z ² , they may be the same or different. It is preferable that the compound represented by 1) or 2 or more types is contained, 1 to 20 types are preferable, and 1 to 15 types are more preferable.

  The content of the compound represented by the general formula (II) is preferably in the range of 1 to 80% by mass, more preferably 1 to 50% by mass, and particularly preferably 1 to 20% by mass.

In the general formula (II), R ⁴ preferably represents an alkyl group having 1 to 12 carbon atoms, an alkoxy group, an alkenyl group having 2 to 12 carbon atoms, or an alkenyloxy group having 2 to 12 carbon atoms. Alkyl groups and straight chain alkenyl groups are more preferred. B ¹ and B ² are each independently formula group 1

Are preferably selected from the structures represented by the formula 2

More preferably, it is selected from the structure represented by:

Z ¹ and Z ² are each independently a single bond, —CH ₂ CH ₂ —, —CH (CH ₃ ) CH ₂ —, —CH ₂ CH (CH ₃ ) —, —CH (CH ₃ ) CH (CH ₃ )-, preferably -C≡C-, -COO- or -OCO-, more preferably a single bond, -CH ₂ CH _2- , -C≡C-, -COO- or -OCO, A bond or —COO— is particularly preferred. L ¹ and L ³ each independently preferably represent —F, —CN, —CF ₃ or —OCF ₃ , and —F or —CN is particularly preferred. As for s and t, it is preferable that s + t represents 1 or 2. Specifically, the compound represented by the general formula (II) includes the general formula (II-1), the general formula (II-2), the general formula (II-3), the general formula (II-4), and the general formula. A compound represented by formula (II-5), general formula (II-6), general formula (II-7), or general formula (II-8) is preferred.

(In the formula, L ¹ and L ³ each independently represent —H, —F or —Cl, and L ² represents —F, —Cl, —CN, —CF ₃ , —OCH ₂ F, —OCHF. ₂ represents -OCF ₃ or _-CH 2 CF _3, ^{X 1} and ^{X 2} are each independently, represent -H or -F.)
The nematic liquid crystal composition further includes a general formula (III)

(In the formula, R ⁵ and R ⁶ represent the same meaning as R ⁴ in the general formula (II), and C ¹ , C ² and C ³ are each independently a trans-1,4-cyclohexylene group ( the two CH ₂ groups not one CH ₂ group or adjacent present in the radical may be substituted by an oxygen atom or a sulfur atom.), 1,4-phenylene group (present in the group 1 or 2 or more CH groups may be substituted with a nitrogen atom.), 1,4-cyclohexenylene group, 1,4-bicyclo [2.2.2] octylene group, piperidine-1, 4-diyl group, naphthalene-2,6-diyl group, decahydronaphthalene-2,6-diyl group or 1,2,3,4-tetrahydronaphthalene-2,6-diyl group, in these groups The hydrogen atom present is replaced by a methyl group, -CN or halogen. May have, u, v and w each independently represent 0 or 1,
Z ³ , Z ⁴ and Z ⁵ are each independently —CH ₂ CH ₂ —, —CH═CH—, —CH (CH ₃ ) CH ₂ —, —CH ₂ CH (CH ₃ ) —, —CH ( CH ₃ ) CH (CH ₃ ) —, —CF ₂ CF ₂ —, —CF═CF—, —CH ₂ O—, —OCH ₂ —, —OCH (CH ₃ ) —, —CH (CH ₃ ) O— , — (CH ₂ ) ₄ —, — (CH ₂ ) ₃ O—, —O (CH ₂ ) ₃ —, —C≡C—, —CF ₂ O—, —OCF ₂ —, —COO—, —OCO -, -COS-, -SCO-, -CH = NN-CH = or a single bond. )
It is preferable to contain 1 type or 2 types or more of the compound represented by this, However, It is preferable to contain 1-20 types, and 1-15 types are more preferable.

  The content of the compound represented by the general formula (III) is in the range of 5 to 95% by mass, preferably 10 to 90% by mass, and more preferably 25 to 90% by mass.

In the general formula (III), R ⁵ and R ⁶ each independently represent an alkyl group having 1 to 12 carbon atoms, an alkoxy group, an alkenyl group having 2 to 12 carbon atoms, or an alkenyloxy group having 2 to 12 carbon atoms. Among them, a linear alkyl group and a linear alkenyl group are more preferable. C ¹ , C ² and C ³ are represented by formula group 3

で表される構造から選ばれることが好ましく、式群４

Is preferably selected from structures represented by formula 4

で表される構造から選ばれることがより好ましい。

More preferably, it is selected from the structure represented by:

Z ³ , Z ⁴ and Z ⁵ are each independently a single bond, —CH ₂ CH ₂ —, —CH═CH—, —CH (CH ₃ ) CH ₂ —, —CH ₂ CH (CH ₃ ) —, It preferably represents —CH (CH ₃ ) CH (CH ₃ ) —, —C≡C—, —COO—, —OCO— or —CH═N—N═CH—, a single bond, —CH ₂ CH ₂ —, —CH═CH—, —C≡C—, —COO—, —OCO— or —CH═N—N═CH— are more preferred. u, v and w are each independently 0 or 1, and the sum of u, v and w is 1 or more, and the sum of u, v and w is preferably 2 or 3. Specifically, general formula (III) includes general formula (III-1), general formula (III-2), general formula (III-3), general formula (III-4), and general formula (III-5). ), General formula (III-6), general formula (III-7), or a compound represented by general formula (III-8) is preferred.

(In the formula, R ⁵ represents the same meaning as R ⁴ in the general formula (II), and Y ¹ , Y ² , Y ³ and Y ⁴ each independently represent —H, —F or a methyl group. , Z ⁷ represents —CH ₂ CH ₂ —, —CH═CH—, —COO—, —OCO—, or a single bond, and Z ⁸ represents —C≡C—, —COO—, —OCO— or -CH = N-N = CH- is represented.)
In General Formula (III-1) to General Formula (III-8), Y ¹ , Y ² , Y ³ and Y ⁴ are preferably —H. Z ⁷ is preferably —CH ₂ CH ₂ —, —CH═CH—, or a single bond. Z ⁸ is preferably —C≡C— or —CH═N—N═CH—.

  The nematic phase upper limit temperature of the liquid crystal composition is preferably 60 ° C. or higher, more preferably 80 ° C. or higher, and particularly preferably 90 ° C. or higher.

  The refractive index anisotropy (Δn) is preferably in the range of 0.06 to 0.30, more preferably in the range of 0.07 to 0.18, but in the case of TN-LCD, 0.07 to 0.16. In the case of STN-LCD, the range of 0.12 to 0.18 is particularly preferable in terms of cell thickness design.

  The dielectric anisotropy (Δε) is preferably from 1 to 20, but more preferably from 1 to 15.

  The liquid crystal composition of the present invention may contain a normal nematic liquid crystal, a smectic liquid crystal, a cholesteric liquid crystal, a dichroic dye, and the like in addition to the above compounds. Further, a chiral agent may be added to prevent the reverse twist domain of the TN-LCD or to induce the helical structure of the STN-LCD. As the chiral agent, a commercially available product can be used. Examples include cholesteryl nonanoate (CN), S-811, R-811, CB-15, and C-15 manufactured by Merck. It is known that the induced helical pitch becomes longer and shorter as the temperature rises, but one of these may be used alone or in combination of two or more, or both may be used in combination of one or more. good. For example, in the TN-LCD, STN-LCD, and TFT-LCD, the quotient d / p between the thickness d between the substrates and the induced spiral pitch p can be selected from the range of 0.001 to 24. Is preferably in the range of 0.1 to 2, more preferably in the range of 0.1 to 1.5, still more preferably in the range of 0.1 to 1, and even more preferably in the range of 0.1 to 0.8. The range of is particularly preferable.

  The nematic liquid crystal composition is useful for TN-LCD, STN-LCD, OCB-LCD, polymer dispersion type liquid crystal display element, phase change type cholesteric liquid crystal display element, but is particularly useful for TN-LCD and STN-LCD. is there. Further, it can be used for a transmissive or reflective liquid crystal display element.

  In the TN liquid crystal display element of the present invention, the twist angle can be selected in the range of 80 ° to 130 ° depending on the purpose, and 85 ° to 110 ° is preferable. In the STN liquid crystal display element of the present invention, the twist angle can be selected in the range of 180 ° to 270 ° according to the purpose, and 220 ° to 260 ° is preferable.

  EXAMPLES Hereinafter, although an Example is given and this invention is further explained in full detail, this invention is not limited to these Examples. Further, “%” in the compositions of the following Examples and Comparative Examples means “% by mass”.

In the examples, the measured characteristics are as follows.
T _NI : Nematic phase-isotropic liquid phase transition temperature (° C)
Δε: Dielectric anisotropy (25 ° C)
Δn: Birefringence (25 ° C)
ρ: Specific resistance (Ω · cm)
Charging time: Liquid crystal composition was injected into the cell and turned on using an electrostatic gun.
After that, it takes time (seconds) to return to the original no voltage application state.
The following abbreviations are used in compound descriptions.
-n Number: -C _n H _{2n + 1} (Alkyl side chain is a number, R is used for representation)
-On: -OC _n H _{2n + 1
-ndm :-( C n H 2n + 1} -CH = CH- (CH 2) m-1)
ndm-: C _n H _{2n + 1} -CH = CH- (CH ₂ ) _m-1-
-Od (m) n: -O ( C n H 2n + 1 -CH = CH- (CH 2) m-2)
_{d (m) nO-: C n} H 2n + 1 -CH = CH- (CH 2) m-2 O-
Linking group
-VO-: -COO- T-: -C≡C- -2-: -CH 2 CH 2 -
Substituent
-CN: -C≡N -F: -F
ring
Ph: 1,4-phenylene group Ph1: 3-fluoro-1,4-phenylene group
Ph2: 3,5-difluoro-1,4-phenylene group
Ma: Pyrimidine-2,5-diyl group Cy: 1,4-cyclohexylene group
(Example 1, Comparative Example 1)
The nematic liquid crystal composition (H1) shown below was prepared, its physical properties were measured, and the results are shown in Table 1.

  The obtained liquid crystal composition H1 has a characteristic that the charging time of the liquid crystal molecules with respect to the temporary application of voltage is relatively long, and abnormal alignment continues for a long time of 300 seconds when effective measures are not taken. ing.

  Liquid crystal compositions (LC1, LC2 and LC3) obtained by adding Emmalbon S-83 or T-20 (manufactured by Toho Chemical Industry Co., Ltd.) as a semipolar organic boron compound to this H1 as Examples 1-2 to 1-4 ) Was prepared. For comparison, as comparative examples 1-1 and 1-2, tetraethylene glycol dimethyl ether (TEG) which is a nonionic surfactant represented by the following general formula in the nematic liquid crystal composition H1.

A liquid crystal composition (R1 and R2) to which was added was prepared. Their specific resistance values and charging characteristics when injected into a 6.0 μm TN cell were measured, and the results are shown in Table 2.

  The nematic liquid crystal composition LC1 shortens the charging time without lowering the specific resistance and the upper limit temperature of the liquid crystal phase as compared with H1 to which no semipolar organic boron compound is added.

  LC2 and LC3 further shorten the charging time without lowering the specific resistance and the liquid crystal phase upper limit temperature. On the other hand, in the case of R1 to which TEG is added, even if 0.1% of 10 times the amount of LC1 is added, the specific resistance is lowered and the liquid crystal phase upper limit temperature is lowered, but there is no effect. R2 to which 20% of 0.2% was added exhibited an effect of shortening the charging time, but the effect was not sufficient, and a decrease in the liquid crystal phase upper limit temperature was observed.

  When TEG is used in this way, the effect cannot be obtained unless the addition amount is further increased, and the resistance value and the liquid crystal phase upper limit temperature are expected to be greatly reduced as compared with the LC1 to LC3 compositions. It could not be used as a composition.

  A nematic liquid crystal composition (H2) shown below was prepared and measured for physical properties, and the results are shown in Table 3.

  In the obtained liquid crystal composition H2, the relaxation time of the liquid crystal molecules with respect to temporary application of voltage is shorter than that of H2, and the charging time in the case of no countermeasure is about 30 seconds. Liquid crystal compositions (LC4 and LC5) in which Hiboron EB-6 (manufactured by Boron International) was added to H2 as a charge transfer complex containing a semipolar organic boron compound were used as Examples 2-1 and 2-2. Prepared. For comparison, as Comparative Examples 2-1 and 2-2, a liquid crystal composition obtained by adding tetraethylene glycol dimethyl ether, which is the same nonionic surfactant as in Example 1, to nematic liquid crystal composition H2 (R3 and R4) was prepared. Their specific resistance values and charging characteristics when injected into a 6.0 μm TN cell were measured, and the results are shown in Table 4.

When the liquid crystal composition H2 having a relatively short charging time is used, the charging time can be shortened to 0.1 seconds or less in LC4 to which 0.01% of EB-6 is added, and the liquid crystal phase temperature range is reduced. I couldn't see it. When 0.1% of EB-6 is added, the upper limit temperature of the liquid crystal phase is lowered. However, as described above, the addition of 0.01% of EB-6 can sufficiently shorten the charging time practically. it can. In contrast, R3 with 0.1% TEG can minimize the decrease in specific resistance, but there is no effect of shortening the charging time, and R4 with 0.2% addition does not decrease the specific resistance. The shortening of the charging time is still insufficient, and addition beyond this level cannot be used as a practical liquid crystal composition because a drastic decrease in the liquid crystal phase upper limit temperature is expected.

  A nematic liquid crystal composition (H3) shown below was prepared to prepare a liquid crystal composition (LC6) composed of 99.99% of H3 and 0.01% of Emalbon S-83 as a semipolar organic boron compound. Further, a liquid crystal composition (LC7) comprising 99.997% of H3 and 0.003% of T-20 was prepared.

  The liquid crystal compositions LC6 and LC7 were also found to have the effect of shortening the charging time.

Example of structure of electro-optical element of the present invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Polarizing plate 2 Substrate 3 Transparent electrode or transparent electrode with active element 4 Alignment film 5 Liquid crystal

Claims (12)

It contains at least one kind of semipolar organic boron compound or a charge transfer complex composed of a semipolar organic boron compound, the number of boron atoms in one molecule of the semipolar organic boron compound is 5 or less, and the specific resistance value is A nematic liquid crystal composition, which is 1.0 × 10 ¹⁰ Ωcm or more and 1.0 × 10 ¹³ Ωcm or less. General formula (I) as a semipolar organoboron compound

The nematic liquid crystal composition of Claim 1 containing the compound which has frame | skeleton represented by these. The nematic liquid crystal composition according to claim 2, comprising a compound having a skeleton represented by general formula (I) and a charge transfer complex composed of an amine compound as the charge transfer complex composed of a semipolar organic boron compound. . General formula (I-1) or general formula (I-2) as a semipolar organic boron compound

(Wherein R ¹ and R ² are each independently a hydrogen atom, a hydroxyl group, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, or 2 carbon atoms) 12 alkenyloxy groups, alkyl groups having 1 to 12 carbon atoms substituted by halogen, alkoxy groups having 1 to 12 carbon atoms substituted by halogen, alkenyl groups having 2 to 12 carbon atoms substituted by halogen, or halogen Represents a substituted alkenyloxy group having 2 to 12 carbon atoms, and A ¹ and A ² each independently represent a single bond, an alkylene group having 1 to 10 carbon atoms, an aryl group having 6 to 18 carbon atoms,-(- _{(CH 2) n O-) m} - (n represents an integer of 1 to 10, m represents an integer of 1 to _{30), -. CH 2 -O} -CO-R 3 -CO- (R Represents a hydrocarbon group having 60 carbon number of 1.) Or ^{_{-CH 2 -O-CO-NH-}} R 3 represents a -NH-CO-, in each p and q independently, integer from 1 to 10 Wherein a plurality of A ¹ and A ² are present, they may be the same or different.) The nematic liquid crystal composition according to claim 2, comprising a compound represented by: A charge transfer complex composed of a semipolar organoboron compound, comprising a charge transfer complex composed of a compound represented by general formula (I-1) or general formula (I-2) and an amine compound 4. The nematic liquid crystal composition according to 4. 6. The nematic liquid crystal composition according to claim 5, wherein the amine compound is a tertiary amine. Formula (II)

Wherein R ⁴ represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an alkyl group having 1 to 12 carbon atoms substituted with at least one halogen, an alkenyl group having 2 to 12 carbon atoms, or at least one halogen. Represents an alkenyl group having 2 to 12 carbon atoms substituted by the above, and one or two or more CH ₂ groups present in these groups are each independently an oxygen atom, as O atoms are not directly bonded to each other, It may be replaced by a sulfur atom, -CO-, -COO-, -OCO- or -OCO-O-, and B ¹ and B ² are each independently a trans-1,4-cyclohexylene group (this two CH ₂ groups not one CH ₂ group or adjacent present in the radical may be substituted by an oxygen atom or a sulfur atom.), there 1,4-phenylene group (in this group 1 Or two or more CH groups may be substituted with nitrogen atoms), 1,4-cyclohexenylene group, 1,4-bicyclo [2.2.2] octylene group, piperidine-1,4-diyl Group, naphthalene-2,6-diyl group, decahydronaphthalene-2,6-diyl group or 1,2,3,4-tetrahydronaphthalene-2,6-diyl group, hydrogen present in these groups The atom may be substituted with -CN or halogen,
s and t each independently represent 0, 1 or 2, but the sum of s and t is 3 or less,
Z ¹ and Z ² independently represent —CH ₂ CH ₂ —, —CH═CH—, —CH (CH ₃ ) CH ₂ —, —CH ₂ CH (CH ₃ ) —, —CH (CH ₃ ). CH (CH ₃ ) —, —CF ₂ CF ₂ —, —CF═CF—, —CH ₂ O—, —OCH ₂ —, —OCH (CH ₃ ) —, —CH (CH ₃ ) O—, — ( CH ₂ ) ₄ —, — (CH ₂ ) ₃ O—, —O (CH ₂ ) ₃ —, —C≡C—, —CF ₂ O—, —OCF ₂ —, —COO—, —OCO—, — Represents COS-, -SCO- or a single bond,
L ¹ and L ³ each independently represent -H, -F or -Cl, and L ² represents -F, -Cl, -CN, -CF ₃ , -OCH ₂ F, -OCHF ₂ or -OCF. ₃ or —CH ₂ CF ₃ , and when there are a plurality of B ¹ , B ² , Z ¹ and Z ² , they may be the same or different. )
Containing one or more compounds represented by
General formula (III)

(In the formula, R ⁵ and R ⁶ each independently represent the same meaning as R ⁴ in the general formula (II), and C ¹ , C ² and C ³ each independently represent trans-1,4-cyclo hexylene group (two CH ₂ groups not one CH ₂ group or adjacent present in this group may be substituted by an oxygen atom or a sulfur atom.), 1,4-phenylene group (the 1 or 2 or more CH groups present in the group may be substituted with a nitrogen atom), 1,4-cyclohexenylene group, 1,4-bicyclo [2.2.2] octylene group, Represents a piperidine-1,4-diyl group, naphthalene-2,6-diyl group, decahydronaphthalene-2,6-diyl group or 1,2,3,4-tetrahydronaphthalene-2,6-diyl group, these The hydrogen atom present in the group is a methyl group, -CN or It may be substituted by Gen,
u, v and w each independently represent 0 or 1;
Z ³ , Z ⁴ and Z ⁵ are each independently —CH ₂ CH ₂ —, —CH═CH—, —CH (CH ₃ ) CH ₂ —, —CH ₂ CH (CH ₃ ) —, —CH ( _{CH 3) CH (CH 3)} -, - CF 2 CF 2 -, - CF = CF -, - CH 2 O -, - OCH 2 -, - OCH (CH 3) -, - CH (CH 3) O- , — (CH ₂ ) ₄ —, — (CH ₂ ) ₃ O—, —O (CH ₂ ) ₃ —, —C≡C—, —CF ₂ O—, —OCF ₂ —, —COO—, —OCO —, —COS—, —SCO—, —CH═N—N═CH— or a single bond is represented. The nematic liquid crystal composition according to claim 1, which comprises one or more compounds represented by formula (1): General formula (II-1), general formula (II-2), general formula (II-3), general formula (II-4), general formula (II-5), general formula (II-6), general formula (II-7) and general formula (II-8)

(Wherein R ⁴ represents an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, or an alkenyloxy group having 2 to 12 carbon atoms, X ¹ and X ² independently represents a hydrogen atom or a fluorine atom, L ¹ and L ³ each independently represent —H or —F, and L ² represents —F, —CN, —CF ₃ , —OCH ₂ F, The nematic liquid crystal composition according to claim 7, comprising at least one compound selected from the group consisting of compounds represented by the formula: —OCHF ₂ , —OCF ₃ or —CH ₂ CF ₃ . General formula (III-1), general formula (III-2), general formula (III-3), general formula (III-4), general formula (III-5), general formula (III-6), general formula (III-7) and general formula (III-8)

Wherein R ⁵ and R ⁶ are each independently an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, or an alkenyloxy group having 2 to 12 carbon atoms. , An alkyl group having 1 to 12 carbon atoms substituted by halogen, an alkoxy group having 1 to 12 carbon atoms substituted by halogen, an alkenyl group having 2 to 12 carbon atoms substituted by halogen, or a carbon number substituted by halogen 2 to 12 alkenyloxy groups, Y ¹ , Y ² , Y ³ and Y ⁴ each independently represent —H, —F or a methyl group, and Z ⁷ represents —CH ₂ CH ₂ —, —CH. ═CH—, —COO—, —OCO—, or a single bond, and Z ⁸ represents —C≡C—, —COO—, —OCO—, or —CH═N—N═CH—. Compound to be Nematic liquid crystal composition according to claim 7, wherein a compound selected from the group containing one or more composed. The nematic liquid crystal composition according to any one of claims 1 to 9, wherein the content of the semipolar organic boron compound or the charge transfer complex composed of the semipolar organic boron compound is in the range of 0.0001 to 1% by mass. The dielectric anisotropy (Δε) is in the range of 1 to 20, and the refractive index anisotropy (Δn) is in the range of 0.06 to 0.16. Nematic liquid crystal composition. The liquid crystal display element which uses the liquid-crystal composition of Claim 11 as a structural member.

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