JPH09255621A - Terphenyl acrylate compound and polymer dispersion type liquid crystal display element using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a terphenyl acrylate compound capable of preparing a reflection type display element having a wider visual angle than that of a display element using a conventional compound, etc. SOLUTION: This terphenyl acrylate compound is represented by the formula [A and B are each H, an acrylate group, etc.; either of A and B is surely the acrylate group; X1 to X3 are each H, F, etc.; n1 to n3 are each an integer of 1-4; the total (n)×X groups are bonded to optional positions of the 2-, 3-, 5- and 6-positions of the phenylene group], e.g. p-terphenyl-4-yl acrylate. The exemplified compound is obtained by reacting 4-methoxyphenyl borate with 4-bromobiphenyl in the presence of tetrakistriphenylphosphinepalladium and sodium carbonate, then converting the resultant compound into a hydroxy compound and subsequently reacting the prepared hydroxy compound with acrylol chloride.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel organic compound, and to form a liquid crystal composition used as an electro-optical display element, a terphenyl acrylate compound, which is one of the materials, and a compound containing the same. The present invention relates to a molecular dispersion type liquid crystal display device.

[0002]

2. Description of the Related Art In recent years, as a bright display element which does not use a polarizing plate, a display element in which a liquid crystal and a polymer are dispersed is drawing attention. The principle of operation of this display element utilizes the difference in the refractive index between the liquid crystal and the polymer.When the refractive index of the liquid crystal and that of the polymer match when an electric field is applied, a transmissive state is shown, and when the electric field is removed, the refractive index differs. In that case, the scattering state is indicated (Tokukaisho Sho 58-501631, which is called NCAP).
In addition, a display element of the opposite mode has been developed, which transmits when no electric field is applied and scatters when an electric field is applied (Mol.Cryst.Liq.Crys
t., 198, 357, (1991), which is called the reverse type).
For these modes, a method of improving visibility by mixing a dye has also been proposed. The polymers used in these display devices have already been used as mesogen groups such as biphenyl derivatives, phenylbenzoate derivatives, benzene rings and benzene rings bonded with a Schiff base, compounds having tolan derivatives, etc. (JP-A-4-22768).
4, JP-A-5-224187, WO 93/08497) are known.

[0003]

However, liquid crystal display devices using these polymers have the drawbacks of poor specific resistance, high driving voltage, insufficient reflectance during scattering, and large viewing angle dependence. was there. Further, there were some kinds of compounds in which the polymer precursor was difficult to dissolve in the liquid crystal composition.

The present invention has responded to the above-mentioned demand in the actual situation, and its purpose is not to reduce the specific resistance value even when irradiated with ultraviolet rays, and the precursor of the polymer may be another type or two. It is an object of the present invention to provide a novel compound which has good compatibility with at least one kind of liquid crystal and can be driven by a low voltage in a display element which is polymerized and phase-dispersed and which is suitable for obtaining a display element which is bright and has excellent reflectance.

[0005]

According to the present invention, there is provided a compound of the general formula

[0006]

Embedded image

(In the above formula, A and B are respectively an acrylate group, a hydrogen atom, a fluorine atom, or a chlorine atom,
Or represents a linear alkyl group having 1 to 10 carbon atoms or a nitrile group, but either A or B is always an acrylate group, and X1 to X3 are each a hydrogen atom, a fluorine atom, a chlorine atom, or A terphenyl acrylate compound represented by a methyl group or a nitrile group, and n1 to n3 each represent an integer of 1 to 4). Further, the display element of the present invention is a display element in which a liquid crystal and a polymer are aligned and dispersed with each other,

[0008]

Embedded image

(In the above formula, X1 to X3 are each a hydrogen atom,
Or a fluorine atom, a chlorine atom, or a methyl group,
Or a nitrile group, and n1 to n3 each represent an integer of 1 to 4), at least a part of which is present in the polymer. In a display element in which liquid crystal and polymer are aligned and dispersed with each other, the phase-separated liquid crystal and polymer may be aligned by shearing. Further, in the display device in which the liquid crystal and the polymer are aligned and dispersed with each other, the liquid crystal and the polymer may be phase-separated in a gel network form. Further, a display device in which a liquid crystal and a polymer are oriented and dispersed to each other is characterized by containing 0.1 to 15% of a terphenyl acrylate compound as a precursor for forming the polymer. A display element in which a liquid crystal and a polymer are aligned and dispersed with each other is characterized by containing a dichroic dye.

Next, a method for producing the terphenyl acrylate compounds (1-a) and (1-b) of the present invention will be described.

[0011]

[Table 1]

Step A-1) The compound (2) is reacted with magnesium in tetrahydrofuran to form a Grignard reagent, and then reacted with triisopropyl borate to obtain the compound (3).

Step A-2) Compound (3) and compound (4) are reacted in a mixed solvent of benzene and ethanol in the presence of tetrakistriphenylphosphine palladium and sodium carbonate to obtain compound (5).

Step A-3) Compound (5) is reacted with boron tribromide in methylene chloride to obtain compound (6).

Step A-4) Compound (6) is reacted with acryloyl chloride in chloroform in the presence of triethylamine to obtain compound (1-a).

[0016]

[Table 2]

Step B-1) Compound (3) and compound (7) are reacted in a mixed solvent of benzene and ethanol in the presence of tetrakistriphenylphosphine palladium and sodium carbonate to obtain compound (8).

Step B-2) Compound (8) is reacted with boron tribromide in methylene chloride to obtain compound (9).

Step B-3) Compound (9) is reacted with acryloyl chloride in chloroform in the presence of triethylamine to obtain compound (1-b).

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail with reference to Examples.

Example 1 [Synthesis of Compound (1-a)] Production of p-terphenyl-4-yl acrylate.

Step A-1) 2.0 g of magnesium was placed in a flask purged with nitrogen, and a solution of 12.5 g of 4-bromoanisole in 100 ml of tetrahydrofuran was slowly added dropwise while stirring with a magnetic stirrer. After confirming that the reaction proceeded with heat generation, the stirring was continued for 15 hours to prepare a Grignard reagent. The flask newly prepared was replaced with nitrogen, and a solution of 25 g of triisopropyl borate dissolved in 10 ml of tetrahydrofuran was placed therein, and the Grignard reagent was added dropwise thereto, followed by stirring for 20 hours. After the reaction solution was extracted with chloroform and washed three times with water, chloroform was distilled off. The residue was recrystallized from a mixed solvent of methanol and water to obtain 5.8 g of 4-methoxyphenylboronic acid.

Step A-2) 2 in a flask purged with nitrogen
50 ml of an aqueous solution of sodium carbonate M and 70 ml of benzene were added, and further 8.9 g of 4-bromobiphenyl and 1.1 g of tetrakistriphenylphosphine palladium were added. A solution prepared by dissolving 5.8 g of 4-methoxyphenylboric acid in 50 ml of ethanol was added dropwise thereto, and the mixture was refluxed for 5 hours. The reaction solution was extracted with chloroform and washed with water, and then chloroform was distilled off. The residue was recrystallized from a mixed solvent of chloroform and methanol to obtain 3.5 g of 4-methoxy-p-terphenyl.

Step A-3) 3.5 g of 4-methoxy-p-terphenyl, 4.0 g of boron tribromide and 50 ml of methylene chloride were placed in an eggplant-shaped flask, and the mixture was stirred at room temperature for 2 hours. The reaction solution was poured into water and the precipitated crystals were filtered and washed with water. The obtained crystals were dried to obtain 2.4 g of 4-hydroxy-p-terphenyl.

Step A-4) Chloroform 100 ml, 4-hydroxy-p-terphenyl in a nitrogen purged flask.
Add 2.4 g and 2 ml of triethylamine and warm in a 40 ° C water bath to dissolve completely. 1.3 ml of acryloyl chloride purified by distillation is slowly added dropwise thereto, and stirring is continued for 5 hours. The reaction solution is washed with dil.HClaq., Saturated NaHCO3aq. And water, then methanol is added to prevent polymerization and chloroform and methanol are distilled off. When crystals appeared during distillation, they were taken out, and methanol was further added to recrystallize them to obtain the compound of the present invention, p-terphenyl-4-yl acrylate.
Obtained 2.3 g. Since this compound was thermally polymerized at 200 ° C., its melting point could not be measured.

(Example 2) [Synthesis of compound (1-b)] 2'-methyl-p-terphenyl-4,4 "-diyl
Production of diacrylate.

Step B-1) 2 in a flask purged with nitrogen
60 ml of an aqueous solution of sodium carbonate M and 70 ml of benzene are added, and further 5 g of 2,5-dibromotoluene and 0.44 g of tetrakistriphenylphosphine palladium are added. A solution prepared by dissolving 6.7 g of 4-methoxyphenylboric acid in 45 ml of ethanol was added dropwise thereto, and the mixture was refluxed for 5 hours. After cooling the reaction solution, the precipitate was taken out by filtration, washed with water and then recrystallized from a mixed solvent of acetone and methanol to give 2'-methyl-
2.3 g of 4,4 "-dimethoxy-p-terphenyl was obtained.
This compound exhibited a liquid crystal phase, and the C-N point was 128.6 ° C and the NI point was 158.7 ° C.

Step B-2) 2.3 g of 2'-methyl-4,4 "-dimethoxy-p-terphenyl, 4.7 g of boron tribromide and 40 ml of methylene chloride were placed in an eggplant-shaped flask and stirred at room temperature for 2 hours. The reaction solution was poured into water, the precipitated crystals were filtered and washed with water, and the obtained crystals were recrystallized from a mixed solvent of acetone and water to give 2'-methyl-4,4 "-dihydroxy-p-ter. 1.9 g of phenyl was obtained.

Step B-3) Chloroform (17 ml), 2'-methyl-4,4 "-dihydroxy-p-terphenyl (1.8 g) and triethylamine (2.7 ml) were placed in a flask purged with nitrogen, and the mixture was in a water bath at 40 ° C. 1.4 g of acryloyl chloride distilled and purified was slowly added dropwise thereto, and the reaction was continued for 3 hours with stirring.The reaction solution was washed with dil.HClaq., Saturated NaHCO3aq., And then methanol to prevent polymerization. Chloroform and methanol are distilled off, and if crystals appear during distillation, they are taken out, recrystallized by adding methanol, and the product is purified by a silica gel column using chloroform as a developing solvent to give the compound of the present invention. 2 '
1.5 g of -methyl-p-terphenyl-4,4 "-diyl diacrylate was obtained. This compound had a liquid crystal layer and had a melting point of 119.0 ° C.

Example 3 [Display Element] As shown in FIG. 1, an electrode 3 made of a transparent electrode film (for example, an ITO film) is formed on glass substrates 1 and 2, and an alignment made of polyimide or the like is formed thereon. Apply the film. Next, rubbing is performed to form the orientation control layer 4, and the glass substrates 1 and 2 are further formed.
Were opposed to each other with the sealant 5 interposed therebetween, and the following composition was injected between the glass substrates to prepare a liquid crystal display cell. The cell gap was 5 μm.

In this embodiment, TL202 and MJ91261 are used as the liquid crystal.
(Both manufactured by Merck), S-1011 (manufactured by Merck) as a chiral component, S-344 (manufactured by Mitsui Toatsu Dye Co.) as a dichroic dye, and Compound 2 of Example 2 of the present invention as a polymer precursor. '-Methyl-p-terphenyl-4,4 "-diyl
Diacrylate and 2'-methyl-p-of existing compounds
Terphenyl-4,4 "-diyl dimethacrylate was used.

The ratio of the composition used is that of TL202 and MJ91261.
A mixture of 90.9% of the mixture of 8: 2, 0.5% of S-1011 and 3.6% of S-344 was used as a base liquid crystal, and the base liquid crystal was further used as a polymer precursor to prepare a compound 2 of Example 2 of the present invention. '-
Liquid crystal composition a mixed with methyl-p-terphenyl-4,4 "-diyl diacrylate 5% and 2'of existing compound
A liquid crystal composition b containing 5% of -methyl-p-terphenyl-4,4 "-diyl dimethacrylate was prepared.

The liquid crystal compositions a and b were enclosed in the above-mentioned empty panel, and the polymer precursor was photopolymerized by ultraviolet irradiation to phase-separate the liquid crystal and the polymer, and the liquid crystal composition a was used. A display element A and a display element B using the liquid crystal composition b were prepared.

The display element thus manufactured is arranged in an optical system as shown in FIG. 2, a signal with a peak value changed by a 1 KHz rectangular wave is applied, and the reflectance is measured while changing the voltage. , Minimum reflectance, maximum reflectance, threshold voltage (voltage value when 5% change from minimum reflectance to maximum reflectance, hereinafter referred to as Vth), saturation voltage (from minimum reflectance to maximum reflectance)
The voltage value when 95% changed, hereinafter referred to as Vsat) was measured. The reflectance was 100% when white fine paper was placed instead of the element. By the way, it has already been investigated that the reflectance of the element has a viewing angle dependency due to the rotation of the element that the value of the reflectance changes depending on the incident direction of light even if the incident angle to the panel is constant. Therefore, in order to match the measurement conditions, the reflectance shown here is a value obtained when the panel is fixed at an incident angle at which the reflectance becomes the largest. Further, in order to express the difference in reflectance depending on the incident direction of light, the value obtained by changing the incident direction of light and dividing the value at which the reflectance becomes the largest by the value at which the reflectance becomes the smallest was defined as the viewing angle dependency. The closer this value is to 1, the smaller the viewing angle dependency. In this way, the display element measurement results shown in the following table were obtained. The measurement was carried out at a cell temperature of 20 ° C.

[0035]

[Table 3]

From the results of this measurement, it can be seen that the use of the compound of the present invention shows that Vth and Vsa are higher than those of the existing compounds.
While the t, the maximum reflectance, and the minimum reflectance have almost the same characteristics, the viewing angle dependence can be greatly improved. The improvement of the viewing angle dependency is an important characteristic when producing a display element, and the significant improvement of this is significant.

As described above, by using the liquid crystal composition of the present invention, the viewing angle dependency is smaller than that of the conventional display element,
A liquid crystal display device in which the display is easy to see was obtained. Further, although the compound of the present invention is compatible with the liquid crystal, it was found that there is no problem in formulating the compositions of Examples, and that the compound has sufficient solubility in the content of the practical polymer precursor. It was Furthermore, the specific resistance of the liquid crystal composition containing the polymer precursor as a display element was 1.0 × 10 11 Ωcm or more, and the voltage holding ratio was 97% or more, which was a value that causes no problem in operation.

Although the TN type liquid crystal display cell is used in the above-mentioned embodiment, the same effect can be obtained when the MIM element, the TFT element and the like are used.

Here, the mixing ratio of the liquid crystal is not limited to the above example. Even if this liquid crystal composition is mixed with another liquid crystal at an arbitrary ratio, it functions as a display element.

The chiral component can be used without being limited to those shown here. As the chiral component, a polymer precursor having a chiral center can also be used. Also, the mixing ratio is not limited to the amount shown here, but if too much is added, the hysteresis tends to increase.

The dichroic dye can be used without being limited to the ones shown here, but if possible, those having little absorption in the ultraviolet region are preferable. Of course, it is more preferable if the two-color ratio is high. The color of the dye can be arbitrarily selected according to the application. The content of the dye is not limited to the amount shown here, but if it is too large, the dye crystallizes or the display becomes dark.

Although the polymerization initiator was not used here, a photosensitizer can also be used. However,
Use with caution because the specific resistance tends to decrease.

The polymer precursor used may be a mixture of other photopolymerizable polymer precursors. The content of the polymer precursor may not be the amount shown here, but if it is too small, the scattering degree becomes weak, and if it is too large, the driving voltage becomes high.

As for the polymerization conditions, ultraviolet rays having a length of 300 nm or longer were used here, but the polymerization can be performed using light shorter than this. However, the specific resistance is likely to decrease, so care must be taken in polymerization. The light intensity was set to 3 mW / cm2, but the light intensity is not limited to this. If the light intensity is weak, the polymerization time is lengthened, and if the light intensity is strong, the polymerization time is shortened. However, if the light intensity is too high, the specific resistance tends to decrease. Slight heating during photopolymerization (20-50
Polymerization is easy when (° C.).

For the reflective electrode, aluminum, silver,
Any electrode that reflects light, such as nickel or chromium, can be used. Alternatively, the electrodes may be transparent and a reflective background plate may be used on the back side of the device.

Any method may be used for the alignment treatment as long as the liquid crystal is aligned.

[0047]

As described above, by using the compound of the present invention, it becomes possible to manufacture a reflection type display device having a wider viewing angle than a display device using conventional compounds and compositions. Further, the compound of the present invention had good compatibility when mixed with any conventional liquid crystal composition. By using the compound of the present invention, a bright power-saving man-machine interface such as a large-capacity display can be easily manufactured at low cost.

[Brief description of drawings]

FIG. 1 is a diagram showing a cross section of a display element according to Example 3 of the present invention.

FIG. 2 is a diagram showing an optical system when measuring electro-optical characteristics of a display element in Example 3 of the present invention.

[Explanation of symbols]

 1, 2 Glass substrate 3 Electrode 4 Alignment control layer 5 Sealant 6 Dye 7 Liquid crystal 8 Polymer (9 Reflective background plate when not using reflective electrode) 10 Display element 11 Light source 12 Imaging lens 13 Photoelectron multiplication tube

Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location G02F 1/13 500 G02F 1/13 500 1/1333 1/1333

Claims (9)

[Claims] 1. A compound of the general formula (In the above formula, A and B each represent an acrylate group, a hydrogen atom, a fluorine atom, a chlorine atom, or a linear alkyl group having 1 to 10 carbon atoms, or a nitrile group, but either A or B Is always an acrylate group, and X1 to X3 are each a hydrogen atom or a fluorine atom,
Alternatively, it represents a chlorine atom, a methyl group, or a nitrile group, and n1 to n3 each represent an integer of 1 to 4. In the formula, Is a total of n at 2,3,5,6 arbitrary positions of the phenylene group.
Represents that each X is bonded). 2. The terphenyl acrylate compound according to claim 1, which is represented by: (3) The terphenyl acrylate compound according to claim 1, which is represented by: 4. In a display device in which a liquid crystal and a polymer are aligned and dispersed with each other, a compound represented by the general formula: (In the above formula, A and B each represent an acrylate group, a hydrogen atom, a fluorine atom, a chlorine atom, or a linear alkyl group having 1 to 10 carbon atoms, or a nitrile group, but either A or B Is always an acrylate group, and X1 to X3 are each a hydrogen atom or a fluorine atom,
Or a chlorine atom, a methyl group, or a nitrile group, and n1 to n3 each represent an integer of 1 to 4), by using at least one component of a terphenyl acrylate compound represented by the general formula: (In the above formula, X1 to X3 each represent a hydrogen atom, a fluorine atom, a chlorine atom, a methyl group, or a nitrile group, and n1 to n3 each represent an integer of 1 to 4)
A polymer-dispersed liquid crystal display device using a terphenyl acrylate compound, characterized in that at least a part of the component represented by the formula (3) is present in the polymer. 5. In a display device in which a liquid crystal and a polymer are aligned and dispersed with each other, as a precursor for forming a polymer, By using a terphenyl acrylate compound represented by: The polymer-dispersed liquid crystal display device using the terphenyl acrylate compound according to claim 4, wherein the component represented by the formula (1) is present at least partially in the polymer. 6. A display device in which a liquid crystal and a polymer are aligned and dispersed with each other, as a precursor for forming a polymer. By using a terphenyl acrylate compound represented by: The polymer-dispersed liquid crystal display device using the terphenyl acrylate compound according to claim 4, wherein the component represented by the formula (1) is present at least partially in the polymer. 7. A display device having a liquid crystal and a polymer aligned and dispersed with each other as a precursor for forming a polymer, represented by the general formula: (In the above formula, A and B each represent an acrylate group, a hydrogen atom, a fluorine atom, a chlorine atom, or a linear alkyl group having 1 to 10 carbon atoms, or a nitrile group, but either A or B Is always an acrylate group, and X1 to X3 are each a hydrogen atom or a fluorine atom,
Or a chlorine atom, a methyl group, or a nitrile group, and n1 to n3 each represent an integer of 1 to 4), and a composition containing 0.1 to 15% of at least one component of the terphenyl acrylate compound A polymer-dispersed liquid crystal display device using the terphenyl acrylate compound according to claim 4. 8. A display device in which a liquid crystal and a polymer are aligned and dispersed with each other, wherein the liquid crystal contains a dichroic dye, and the compound represented by the general formula: (In the above formula, X1 to X3 each represent a hydrogen atom, a fluorine atom, a chlorine atom, a methyl group, or a nitrile group, and n1 to n3 each represent an integer of 1 to 4)
The polymer-dispersed liquid crystal display device using the terphenyl acrylate compound according to claim 4, wherein the component represented by the formula (1) is present at least partially in the polymer. 9. A display device in which a liquid crystal and a polymer are oriented and dispersed to each other, wherein at least one of the liquid crystal and the polymer contains or exists a chiral component, and a compound represented by the general formula: (In the above formula, X1 to X3 each represent a hydrogen atom, a fluorine atom, a chlorine atom, a methyl group, or a nitrile group, and n1 to n3 each represent an integer of 1 to 4)
The polymer-dispersed liquid crystal display device using the terphenyl acrylate compound according to claim 4, wherein the component represented by the formula (1) is present at least partially in the polymer.