JPH10158268A - Optically active monomer, liquid crystal polymer and optical element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a new optically active monomer, having a specific polymerizable group and an optically active structure capable of providing a liquid crystalline polymer capable of readily forming a Grandjean oriented film in a good monodomain state, treatable by the orientation in a short time and stably fixable in a glassy state. SOLUTION: This optically active compound is represented by formula I (R<1> is H or methyl; A and B are each an organic group) or formula II, e.g. (4S,8R)-4- 4-[2-(acryloyloxy)ethoxylphenyl}carbonyloxy-8-(4cyanophenyl) carbonyloxy-2,6-dioxabicyclo[3.3.0]octane. The exemplified compound is obtained by esterifying 4-2propenoyloxy)benzoic acid with (4S,8R)-4-hydroxy-8-(4 cyanophenyl)carbonyloxy-2,6-dioxabicyclo[3.3.0]octane.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optically active monomer suitable for forming a liquid crystal display device, a liquid crystal polymer thereof, and a circular dichroic optical element using the same.

[0002]

2. Description of the Related Art In a polarizing plate in which a dichroic dye or the like is adsorbed on a stretched film of polyvinyl alcohol or the like, the intensity of incident light is 5%.
Since 0% or more is absorbed and cannot be used effectively, and it is difficult to achieve high luminance and low power consumption of a liquid crystal display device or the like, a circular dichroic optical element is expected. this is,
The helical axis of the liquid crystal molecules is oriented in the direction of the Grand Jean perpendicular to the optical element, and about half of the light of a certain wavelength in natural light incident parallel to the helical axis (incident angle 0 °) is shifted to the right ( Or left) reflected as circularly polarized light, and about the other half transmitted as left (or right) circularly polarized light, and its wavelength λ is given by the formula: λ = n
Determined by p (where n is the average refractive index of the liquid crystal and p is the helical pitch of the cholesteric phase), and the left and right sides of the reflected circularly polarized light are determined by the helical state of the cholesteric phase and coincide with the helical turning direction. This is because there is a possibility that reflected light may be used in addition to the transmitted light due to the separation.

Conventionally, optical elements of circular dichroism include:
There have been known liquid crystal cholesteric liquid crystals composed of a low-molecular-weight monomer which are sealed between substrates such as glass in an aligned state, and liquid crystal polymers exhibiting a cholesteric liquid crystal phase (JP-A-55-21479, U.S. Pat. Patent Specification No. 5332522). However, the former low molecular weight is thick and heavy due to the use of a substrate, and thus has a problem of hindering the lightness and thinness of the liquid crystal display device. There is also a problem that the alignment state of the liquid crystal, for example, the pitch tends to change with temperature or the like.

On the other hand, in the case of using the latter liquid crystal polymer, it is difficult to obtain a solidified product such as a film having a good alignment state as in the case of a low molecular weight polymer, or a long time such as several hours is required for the alignment treatment. In any case, it is difficult to obtain a solid-state circular dichroic dichroic optical element, particularly for visible light, because the glass transition temperature is low and the durability is inadequate due to insufficient durability. Was.

Various attempts have been made to change the combination of monomers, particularly the cholesteric phase-providing monomer, for the purpose of improving the solidification state, but at present the problems of poor liquid crystal alignment and heat resistance have not been overcome. . Incidentally, in order to obtain a cholesteric liquid crystal polymer having a selective reflection wavelength in the visible light region, the copolymerization ratio of the monomer having a cholesteric phase needs to be about 15% by weight or more. Properties are greatly reduced.

[0006]

The present invention provides a monomer having a large torsion force defined by 10 ⁴ / [selective reflection wavelength (nm) × copolymerization ratio (mol%)], thereby obtaining a film-forming property. Liquid crystal that can easily control the helical pitch of the cholesteric phase, form a good monodomain state of the Grand Jean alignment by short-time alignment treatment such as several minutes, and stably fix it to the glass state Obtaining a polymer, thereby obtaining a thin and light circular dichroic optical element made of a solidified liquid crystal polymer, whose orientation state such as pitch is unlikely to change at a practical temperature and excellent in durability and storage stability. That is the task.

[0007]

The present invention provides a compound represented by the general formula (a): Wherein R ¹ is hydrogen or a methyl group, and A and B are organic groups, and a cholesteric monomer having a structural unit comprising the optically active monomer. Provided is an optical element characterized by having a side-chain type liquid crystal polymer which may exhibit a liquid crystal phase, and having a solidified layer of a cholesteric liquid crystal phase which is made of the liquid crystal polymer and which is oriented in the form of a Grand Jean and exhibiting circular dichroism. Is what you do.

[0008]

According to the optically active monomer of the present invention, a liquid crystal polymer having excellent orientation and heat resistance can be obtained with a small amount of use due to its large torsional force. In addition, the obtained liquid crystal polymer can easily form a film with good mono-domain state of Grand Jean alignment with good film formability, and the alignment treatment can be achieved in a short time such as several minutes, and is stably fixed to the glass state. Can be As a result, it is possible to efficiently form a circular dichroic optical element that is made of a thin and light liquid crystal polymer solidified, and whose orientation state such as pitch is difficult to change at practical temperature and has excellent durability and storage stability. The control of the phase helical pitch is easy, and an optical element showing circular dichroism in the visible light region can be easily obtained.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The optically active monomer of the present invention is represented by the following general formula (a). (However, R ¹ is hydrogen or a methyl group, and A and B are organic groups.)

Particularly preferred optically active monomers from the viewpoint of torsional force are those represented by the following general formula (b).

Accordingly, the optically active monomer represented by the general formula (b) is a compound in which A in the general formula (a) is represented by the general formula (a1): COO (CH ₂ ) _m R ² Z And B is represented by the following general formula (a2).

In the above general formula (b), m is 1 to 6
R ² is represented by the following chemical formula, and Z is COO— or O—.

Y is OCO- or O-, n is 0 ≦ n ≦
3, R ³ is -C _d H _{2d + 1} when n = 0, and is -OC _d H _{2d + 1} , -CN or -Cl when 1 ≦ n ≦ 3, wherein d is 0 ≦ d ≦ 3.

Particularly preferred are those wherein R ² in the general formula (b) is as follows: And B in the general formula (a) is as follows.

The general formula (b) and therefore the general formula (a)
The optically active monomer represented by can be synthesized by an appropriate method. Incidentally, a synthesis example of the monomer represented by the formula (b1) is shown below.

That is, as shown in the following reaction formula, first, ethylene chlorohydrin and 4-hydroxybenzoic acid are heated and refluxed in an aqueous alkali solution using potassium iodide as a catalyst to obtain 4- (2-hydroxyethoxy) benzoic acid. After
It was reacted with vinyl (meth) acrylate in THF (tetrahydrofuran) to which lipase PS and a small amount of p-methoxyphenol were added to give (meth) acrylate (4).
-(2-propenoyloxyethoxybenzoic acid)
DCC in methylene chloride
The target compound (b1) can be obtained by esterification with an isosorbide derivative in the presence of (dicyclohexylcarbodiimide) and DMAP (dimethylaminopyridine).

In the above, the isosorbide derivative added in the final step is prepared, for example, by adding DHP (3,4-dihydro-2H) in THF in which isosorbide and a small amount of p-toluenesulfonic acid (TsOH) hydrate are dissolved. -Pyran) to protect one hydroxyl group with THP (tetrahydropyranyl), and then react the isosorbide with 4-cyanobenzoic acid in ethyl acetate in the presence of DCC and DMAP. Can be obtained by, for example, separating the THP-protected ester from the filtrate from which the THP-protected group is removed by treating it with hydrochloric acid or the like. The reaction process is illustrated below.

[0018]

Therefore, the other optically active monomer represented by the general formula (a) can be synthesized according to the above method using an appropriate raw material having a target introducing group.

The liquid crystal polymer of the present invention is prepared using at least an optically active monomer represented by the general formula (a). Accordingly, a side chain type liquid crystal polymer having at least a structural unit composed of an optically active monomer represented by the general formula (a), that is, a structural unit represented by the following general formula (c), based on at least such a monomer unit, It is a liquid crystal polymer exhibiting a medium cholesteric liquid crystal phase.

General formula (c): (However, R ¹ , A, and B conform to the case of the general formula (a).)

Therefore, the liquid crystal polymer of the present invention is a homopolymer or a copolymer using one or more of the optically active monomers represented by the general formula (a), and other monomers, for example, a polymer exhibiting a nematic liquid crystal phase. Or a combination of two or more of optically active monomers or other types of optically active monomers, or a mixed polymer obtained by mixing these polymers in an appropriate combination.

The liquid crystal polymer of the present invention can be preferably used for forming optical elements having various optical functions such as a retardation plate, a notch filter, and a film (polarizing plate) exhibiting circular dichroism. In particular, a compound exhibiting a cholesteric liquid crystal phase can be preferably used for forming a circularly polarized dichroic optical element by subjecting it to a Grandian orientation.

A liquid crystal polymer which can be preferably used for forming a circularly polarized dichroic optical element, particularly one having a selective reflection wavelength in the visible light region, is one of the optically active monomers represented by the above general formula (b). Alternatively, a copolymer containing two or more kinds and one or two or more kinds of monomers forming a polymer exhibiting a nematic liquid crystal phase, in particular, 1 to 40% by weight of the optically active monomer unit and 99% of the nematic monomer
It is a copolymer containing about 60% by weight.

If the content of the optically active monomer unit in the copolymer is too small, the formation of a cholesteric liquid crystal phase will be poor, and if it is too high, the liquid crystallinity will be poor. From this point, the copolymerization ratio of the optically active monomer unit is preferably
It is 2 to 38% by weight, especially 3 to 35% by weight, especially 5 to 30% by weight.

A mixture of a polymer having the optically active monomer represented by the above general formula (b) as a total monomer component and a polymer having a monomer forming a polymer exhibiting a nematic liquid crystal phase as a total monomer component is also a circular dichroism. In particular, it can be preferably used for forming an optical element having a selective reflection wavelength in the visible light region. The mixing ratio can be the same as in the case of the above-mentioned copolymer.

In the above, the monomer forming the polymer exhibiting the nematic liquid crystal phase is not particularly limited.
An appropriate one can be used. Above all, those represented by the following general formula (d) can be preferably used in terms of optical characteristics and the like. (However, R ⁴ is hydrogen or a methyl group, e is an integer of 1 to 6, X is CO ₂ — or OCO—, p and q are 1 or 2, and p + q = 3 is satisfied.)

The monomer represented by the general formula (d) can also be synthesized according to the above-mentioned general formula (a) by using an appropriate raw material having an intended introduction group.

The molecular weight of the liquid crystal polymer which can be preferably used for forming an optical element, particularly, one having a liquid crystal polymer as a solidified layer composed of a cholesteric liquid crystal phase or the like, is preferably 2,000 to 100,000, and more preferably 2.55,000 based on the weight average molecular weight. ~ 50,000. If the molecular weight is too low, the film formability may be poor,
If the amount is excessive, the orientation as a liquid crystal, particularly the monodomain formation via a rubbing orientation film is poor, and it may be difficult to form a uniform orientation state. For the formation of the optical element,
A liquid crystal polymer having a glass transition temperature of 80 ° C. or more can be preferably used from the viewpoints of the durability of the device, the stability of the orientation characteristics such as pitch to temperature change in practical use, and the invariability.

The preparation of a liquid crystal polymer such as a homopolymer or a copolymer can be carried out according to a conventional polymerization method of an acrylic monomer such as a radical polymerization method, a cation polymerization method or an anion polymerization method. When the radical polymerization method is applied, various polymerization initiators can be used, but the decomposition temperature of azobisisobutyronitrile or benzoyl peroxide is not high, and the decomposition is performed at an intermediate temperature which is not low. Those can be preferably used from the viewpoint of stability of synthesis and the like.

In the liquid crystal polymer of the present invention, the pitch of the cholesteric liquid crystal changes based on the content of the monomer unit represented by the general formula (a) in the copolymer or the mixture. Since the wavelength exhibiting circular dichroism is determined by the pitch, the wavelength exhibiting circular dichroism by controlling the content of the monomer unit represented by the general formula (a), particularly the general formula (b). Can be adjusted.

The wavelength range exhibiting circular dichroism can also be adjusted by mixing two or more liquid crystal polymers having different wavelength ranges exhibiting circular dichroism. Therefore, an optical element that exhibits circular dichroism with respect to light in the visible light region can be easily obtained as in the examples described later.

The optical element can be formed by a method according to a conventional alignment treatment. By way of example, an alignment film made of polyimide, polyvinyl alcohol, etc. is formed on a substrate, rubbed with a rayon cloth or the like, and then a liquid crystal polymer is spread on it to obtain a glass transition temperature or higher and an isotropic phase. A method in which the liquid crystal polymer molecules are heated to a temperature lower than the transition temperature and cooled to a temperature lower than the glass transition temperature in a state where the liquid crystal polymer molecules are aligned to form a glassy state, and a solidified layer in which the orientation is fixed is formed. In that case, an optical element exhibiting circular dichroism can be formed by causing liquid crystal polymer molecules to undergo Grand Jean alignment.

As the substrate, for example, an appropriate substrate such as a film made of a plastic such as triacetyl cellulose, polyvinyl alcohol, polyimide, polyarylate, polyester, polycarbonate, polysulfone, polyether sulfone, or epoxy resin, or a glass plate Can be used. The solidified layer of the liquid crystal polymer formed on the substrate can be used as an integral element with the substrate for the optical element as it is, or can be peeled off from the substrate and used as an optical element composed of a film or the like.

The liquid crystal polymer can be developed by a heating and melting system or can be developed as a solution using a solvent. As the solvent, for example, an appropriate solvent such as methylene chloride, cyclohexanone, trichloroethylene, tetrachloroethane, N-methylpyrrolidone, tetrahydrofuran, or the like can be used. The development can be performed by a suitable coating machine such as a bar coater, a spinner, and a roll coater.

The thickness of the solidified layer of the liquid crystal polymer to be formed is
If it is too thin, it will be difficult to show optical functions such as circular dichroism, and if it is too thick, it will not show optical functions such as circular dichroism due to poor uniform alignment, or it will take a long time for the alignment treatment. , 0.1-30 μm, especially 0.3-20 μm,
In particular, 0.5 to 10 μm is preferable. In the formation of the optical element, various additives other than the liquid crystal polymer according to the present invention, such as polymers, stabilizers, plasticizers, and other inorganic or organic materials, or metals, can be added as necessary.

In the optical element exhibiting circular dichroism of the present invention, a single layer of a liquid crystal polymer solidified layer usually has a limit in a wavelength region exhibiting circular dichroism. The limit is usually around 10
Although it is wide in the wavelength range of 0 nm, it is desired to exhibit circular dichroism in the entire visible light region or in a wide region when applied to a liquid crystal display device or the like.

In the present invention, by laminating a solidified layer of a liquid crystal polymer exhibiting circular dichroism with respect to light of different wavelengths, the wavelength region exhibiting circular dichroism can be expanded. Such lamination is advantageous not only for expansion of the wavelength range, but also for addressing wavelength shift of obliquely incident light.
For lamination, two or three or more layers can be laminated in a combination in which the center wavelengths of reflected circularly polarized light are different.

Incidentally, the center wavelength of the reflected circularly polarized light is 300
Combination of liquid crystal polymer solidified layer of ~ 900 nm to reflect circularly polarized light in the same direction, and different central wavelength of selective reflection,
In particular, using different combinations of 50 nm or more,
By stacking up to six types, an optical element exhibiting circular dichroism in a wide wavelength range of the visible light region can be formed. At the time of lamination, it is preferable to reduce surface reflection loss at each interface by using an adhesive or the like.

In the above, the combination of those which reflect circularly polarized light in the same direction is used to prevent the polarization state of the circularly polarized light reflected by each layer from being different in each wavelength region by aligning the phase state of the reflected light. The purpose of the present invention is to improve the efficiency when reusing the reflected circularly polarized light via the method described above.

The optical element exhibiting circular dichroism of the present invention comprises:
Based on the circular dichroism, the incident light is separated into left and right circularly polarized light, supplied as transmitted light and reflected light, and the reflected light is reused through a reflective layer or the like to improve the light use efficiency. Therefore, it can be preferably used as an illumination device such as a polarizing plate or a backlight in various devices such as a direct-view type liquid crystal display device.

In the illuminating device, for example, an optical element exhibiting circular dichroism is arranged on a light emitting side of a side light type light guide plate for emitting incident light from a side surface from one of upper and lower surfaces. It can be obtained by a method or the like.
In addition, by disposing a reflection layer on the back surface of the light guide plate, the circularly polarized light reflected via the optical element can be reflected via the reflection layer on the back surface and incident on the optical element again.

On the other hand, when it is used as a polarizing plate for obtaining linearly polarized light, it is an optical element in which circularly polarized light via an optical element having circular dichroism is combined with a retardation layer for linearly polarizing the circularly polarized light. The retardation layer may be provided on either the transmission side or the reflection side of the optical element exhibiting circular dichroism, but is provided on the transmission side in the above-described illumination device.

The phase difference layer for converting circularly polarized light into linearly polarized light changes the phase of circularly polarized light emitted from the optical element,
The purpose is to convert to a state having a large amount of linearly polarized light components. By converting the light into a state having a large amount of linearly polarized light components, a bright display by direct incidence on the liquid crystal cell and a bright display through incidence on a polarizing plate attached to the liquid crystal cell can be realized.

Therefore, as the retardation layer, circularly polarized light passing through the optical element can be formed into a large amount of linearly polarized light corresponding to a phase difference of 波長 wavelength, and light of another wavelength can be used as the linearly polarized light. Those having a major axis direction as parallel as possible and capable of converting into flat elliptically polarized light as close to linearly polarized light as possible can be preferably used.

The retardation layer can be formed of an appropriate material, and preferably provides a transparent and uniform retardation. In general, a retardation plate made of a stretched film of a plastic such as polycarbonate, a unidirectionally oriented or twisted oriented nematic liquid crystal polymer, and the like are used. The retardation of the retardation layer can be appropriately determined according to the wavelength range of circularly polarized light by the optical element. By the way, in the visible light region, from the viewpoint of wavelength characteristics and practicality, the fact that most retardation plates show wavelength dispersion of positive birefringence than their material characteristics, and the retardation is small, In particular, those giving a phase difference of 100 to 200 nm can be preferably used in many cases.

The retardation layer can be formed as one layer or two or more layers. In the case of a single-layer retardation layer, the smaller the wavelength dispersion of birefringence, the better the polarization state can be made uniform for each wavelength, which is preferable. On the other hand, the formation of a superposed layer of the retardation layer is effective for improving the wavelength characteristics in the wavelength range, and the combination thereof may be appropriately determined according to the wavelength range or the like.

In the case where two or more retardation layers are formed in the visible light region, a layer having a phase difference of 100 to 200 nm is included as one or more odd-numbered layers as described above, so that the linear polarization component is large. It is more preferable to obtain light. 100-20
Layers other than the layer giving a phase difference of 0 nm are usually 200 to 40
It is preferable to form a layer having a phase difference of 0 nm from the viewpoint of improving wavelength characteristics, but the present invention is not limited to this.

[0049]

【Example】

Example 1 300 parts (by weight, the same applies hereinafter) of potassium hydroxide was dissolved in a mixed solution of 700 ml of ethanol and 300 ml of water, and 276 parts of 4-hydroxybenzoic acid and a catalytic amount of potassium iodide were dissolved in the solution. In a heated state, 177 parts of ethylene chlorohydrin were gradually added, and the mixture was refluxed for about 15 hours.
Ethanol was distilled off from the obtained reaction solution, and the residue was taken into 2 liters of water. The aqueous solution was washed twice with diethyl ether, hydrochloric acid was added to make an acidic solution, and the precipitate was separated by filtration, dried and re-used with ethanol. Crystallization gave 298 parts of 4- (2-hydroxyethoxy) benzoic acid (82% yield).

Next, after dissolving 18.2 parts of the above 4- (2-hydroxyethoxy) benzoic acid in 300 ml of THF, 19.5 parts of vinyl acrylate and lipase PS were added thereto.
After adding 18 parts and a small amount of p-methoxyphenol,
Stirred at C for 3 hours. From the obtained reaction solution, lipase PS
After filtration, the filtrate was evaporated under reduced pressure, and the resulting solid was recrystallized from a 2-butanone / hexane: 2/1 mixture to obtain (4).
-(2-propenoyloxyethoxybenzoic acid) 17.
5 parts (74% yield) were obtained.

On the other hand, 10.0 parts of isosorbide was dissolved by stirring at room temperature with 0.5 part of p-toluenesulfonic acid hydrate and 100 ml of THF, and THF 50 was added to the solution.
5.76 parts of DHP diluted in 1 ml were added dropwise over 90 minutes, then stirred at room temperature for 90 minutes, the solvent was distilled off from the resulting reaction solution, and it was dissolved in 250 ml of methylene chloride. After washing successively with a saline solution, a 1N-HCl aqueous solution, a saturated saline solution, a saturated sodium hydrogen carbonate aqueous solution, and a saturated saline solution, the organic layer is dried over magnesium sulfate, and the solvent is distilled off, followed by silica gel column chromatography purification (methylene chloride / diethyl chloride). Ether: 1/1), and isosorbide 4.7 in which the hydroxyl group on one side is protected with THP.
9 parts were obtained.

Next, 4.21 parts of the above-mentioned THP one-side protected isosorbide, 2.96 parts of 4-cyanobenzoic acid, DCC
4.52 parts, DMAP 0.28 part and ethyl acetate 110
After stirring at room temperature for about 2 hours, the precipitated DCC urea was separated by filtration, and ethyl acetate was added so that the filtrate became 150 ml. Then, each of 150 ml of a saturated aqueous solution of sodium hydrogencarbonate, a saturated aqueous solution of sodium chloride, and an aqueous solution of 1N HCl were added. Then, the extract was washed successively with saturated saline and dried over magnesium sulfate, and the solvent was distilled off to obtain 7.81 parts of a THP protected ester. Its purity by liquid chromatography was 83%.

In a 300 ml eggplant type flask, 7.44 parts of the unpurified THP-protected ester obtained above was added to THF
Dissolve in 75 ml and reflux and add 12N HCl 3
After refluxing for 15 minutes, THF was distilled off and the residue was dissolved in 200 ml of methylene chloride, washed twice with 200 ml of saturated saline, dried over magnesium sulfate, and the solvent was distilled off, followed by column chromatography purification (methylene chloride / methylene chloride). Diethyl ether: 6
/ 1 to 0/1) to obtain 4.63 parts (purity 97%, yield 91%) of the above terminal cyanated isosorbide derivative.

Finally, 2.55 parts of the above-obtained 4- (2-propenoyloxyethoxybenzoic acid), 2.83 parts of a terminal cyanated isosorbide derivative, 2.33 parts of DCC and 0.138 part of DMAP were combined with methylene chloride. After stirring at room temperature for 4.5 hours in 70 ml, the precipitated DCC urea was separated by filtration, methylene chloride was added so that the filtrate became 200 ml, and then 200 ml of 1N-HCl aqueous solution, saturated saline, and saturated carbonate were added. The extract was washed successively with an aqueous sodium hydrogen solution and a saturated saline solution, dried over magnesium sulfate, and the solvent was distilled off to purify the residue by column chromatography (methylene chloride / diethyl ether:
6/1) to obtain 1.39 parts of an optically active monomer represented by the above formula (b1) (purity: 90%, yield: 23%).

The proton N of the optically active monomer obtained above
The analysis results by MR and IR are shown in FIGS.

Embodiment 2 0.168 parts (0.31 mmol) of the optically active monomer represented by the formula (b1) and 1.56 parts (3.78 mmol) of the monomer represented by the above formula (d1) are dissolved by heating in 16.5 ml of tetrahydrofuran. After stabilizing at 55 to 60 ° C., the inside of the reactor was replaced with nitrogen gas, and 0.5 ml of a tetrahydrofuran solution in which 0.5 part of azobisisobutyronitrile was dissolved in the absence of oxygen was added dropwise for polymerization treatment for 3 hours. The reaction solution was gradually poured into 150 ml of diethyl ether with stirring to obtain a white polymer precipitate, which was separated by filtration and dried to obtain a copolymer (yield: 58%). This copolymer has a glass transition temperature of 90 ° C. and an isotropic phase transition temperature of 26.
It showed a cholesteric structure at 0 ° C.

Example 3 According to Example 2, 0.15 part (0.28 mmol) of the optically active monomer represented by the formula (b1) and 1.64 parts (3.98 mmol) of the monomer represented by the formula (d1) ), The glass transition temperature is 92 ° C and the isotropic phase transition temperature is 275 ° C.
A cholesteric structure was obtained.

Example 4 According to Example 2, 0.13 parts (0.24 mmol) of the optically active monomer represented by the formula (b1) and 1.96 parts (4.76 mmol) of the monomer represented by the formula (d1) ), The glass transition temperature is 95 ° C and the isotropic phase transition temperature is 282 ° C.
A cholesteric structure was obtained.

Example 5 A polyvinyl alcohol layer having a thickness of about 0.1 μm was provided on a glass plate, rubbed with a rayon cloth, and treated with a 30% by weight solution of the copolymer obtained in Example 2 in cyclohexanone. Was applied by a spinner, dried, heated and treated at 150 ° C. for 5 minutes, and allowed to cool at room temperature to fix the orientation of the liquid crystal polymer in a glassy state. The thickness of this liquid crystal polymer is 2 μm, and the optical element formed integrally with the glass plate exhibits circular dichroism that reflects blue-violet light specularly,
This reflected light had a wavelength of 405 to 485 nm. FIG. 3 shows the transmission characteristics of the optical element.

Example 6 The procedure of Example 5 was repeated, except that the copolymer obtained in Example 3 was used. An optical element of 555 nm was obtained. FIG. 4 shows the transmission characteristics of the optical element.

Example 7 In the same manner as in Example 5 except that the copolymer obtained in Example 4 was used, circular dichroism in which red light was specularly reflected was exhibited, and the wavelength of the reflected light was 642 to 642. An optical element of 740 nm was obtained. FIG. 5 shows the transmission characteristics of the optical element.

Example 8 Optical elements obtained according to Examples 5, 6, and 7 were laminated with an acrylic adhesive layer interposed therebetween, and a wavelength of 405 to 55 based on reflected light.
An optical element exhibiting circular dichroism in the range of 5 nm and 642 to 740 nm was obtained.

Example 9 16.8 parts of a homopolymer of an optically active monomer represented by the formula (b1) prepared according to Example 2 and a compound represented by the formula (d1)
An optical element was obtained according to Example 5 using a mixture of 156 parts of a homopolymer of a monomer represented by the following formula: This optical element exhibits circular dichroism to reflect blue-violet light specularly,
The wavelength of the reflected light was 415-495 nm.

In the above, the homopolymer of the monomer of the formula (b1) had a glass transition temperature of 80 ° C. and an isotropic phase transition temperature of 210 ° C., and the alignment characteristics of the liquid crystal exhibited a cholesteric structure. . The homopolymer of the monomer of the formula (d1) has a glass transition temperature of 85.
C., the isotropic phase transition temperature was 287 ° C., and the alignment characteristics of the liquid crystal showed a nematic structure. The mixed polymer had a glass transition temperature of 90 ° C. and an isotropic phase transition temperature of 232 ° C., and the alignment characteristics of the liquid crystal showed a cholesteric structure.

Example 10 50.0 parts of isosorbide, 53.5 p-chlorobenzoic acid
And 1.4 parts of DMAP were stirred with 500 ml of methylene chloride on an ice bath, and DCC7 dissolved in methylene chloride was added thereto.
7.6 parts was added dropwise, and the mixture was stirred on an ice bath for 2.5 hours and at room temperature overnight, and the precipitated DCC urea was separated by filtration.
Methylene chloride was added to make up to
The mixture was washed successively with 00 ml of a 1N-HCl aqueous solution, a saturated saline solution, a saturated sodium hydrogen carbonate aqueous solution, and a saturated saline solution, dried over magnesium sulfate, evaporated, and purified by silica gel column chromatography (methylene chloride / diethyl ether: 1 / l).
1) was performed to obtain 14.2 parts of a terminal chlorophenylated isosorbide derivative.

Next, 14.2 parts of the above-mentioned terminal chlorophenylated isosorbide derivative and 12.9 parts of 4- (2-propenoyloxyethoxy) benzoic acid were added to methylene chloride 180.
The mixture was stirred together with 0.5 ml of DMAP and a small amount of dibutylhydroxytoluene, and 11.3 parts of DCC dissolved in 10 ml of methylene chloride was added little by little, and the ice bath was removed. After stirring overnight, the precipitated DCC urea was separated by filtration, methylene chloride was added so that the filtrate became 500 ml, and 500 ml of 1 ml each was added.
The extract was washed successively with an N-HCl aqueous solution, a saturated saline solution, a saturated sodium bicarbonate aqueous solution, and a saturated saline solution, dried over magnesium sulfate, the solvent was distilled off, and the resulting solid was re-used with a mixed solution of toluene / hexane: 70 ml / 50 ml. Crystallized, and the following formula (b)
9.34 of the optically active monomer represented by 2) was obtained (purity: 95%). The analysis results of the optically active monomer by proton NMR and IR are shown in FIGS.

[0067]

Example 11 1.50 of the optically active monomer represented by the above formula (b2)
Part (2.98 mmol) and 13.3 parts (32.1 mmol) of the monomer represented by the above formula (d1) in a mixed solvent of 4 parts of dimethylacetamide / 1 part of tetrahydrofuran 9
2.0 ml of the mixed solvent solution in which 0.29 part of azobisisobutyronitrile was dissolved by heating and dissolving in 5 parts, stabilizing at 55 to 60 ° C., replacing the inside of the reactor with nitrogen gas, and dissolving 0.29 part of azobisisobutyronitrile in the absence of oxygen. Was added dropwise, and the mixture was polymerized for 4.5 hours. The reaction solution was subjected to gravity filtration, and methanol was added to the filtrate while stirring vigorously.
20 ml was quickly added to obtain a white polymer precipitate,
It was washed twice with 50 ml of a mixed solvent of 3 parts of methanol / 2 parts of tetrahydrofuran, and dried to obtain a copolymer. This copolymer had a cholesteric structure having a glass transition temperature of 99 ° C. and an isotropic phase transition temperature of 262 ° C.

Example 12 In the same manner as in Example 5 except that the copolymer obtained in Example 11 was used, the copolymer exhibited specular circular dichroism reflecting blue-violet light,
An optical element having a reflected light wavelength of 385 to 460 nm was obtained. FIG. 8 shows the transmission characteristics of the optical element.

[Brief description of the drawings]

FIG. 1 shows the proton N of the optically active monomer obtained in Example 1.
Analysis diagram by MR

FIG. 2 is an IR analysis chart of the optically active monomer obtained in Example 1.

FIG. 3 is a graph showing transmission characteristics of the optical element obtained in Example 5.

FIG. 4 is a graph showing transmission characteristics of the optical element obtained in Example 6.

FIG. 5 is a graph showing transmission characteristics of the optical element obtained in Example 7.

FIG. 6 is an analysis diagram of the optically active monomer obtained in Example 10 by proton NMR.

FIG. 7 is an IR analysis chart of the optically active monomer obtained in Example 10.

FIG. 8 is a graph showing transmission characteristics of the optical element obtained in Example 12.

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁶ Identification code FI G02F 1/1333 G02F 1/1333 1/1335 510 1/1335 510

Claims (9)

[Claims] 1. The general formula (a): (Wherein, R ¹ is hydrogen or a methyl group, and A and B are organic groups). 2. The method according to claim 1, wherein A in the general formula (a) is represented by the general formula (a1): COO (CH ₂ ) _m R ² Z (where m is an integer of 1 to 6, and R ² is Represented by a chemical formula, Z is COO- or O-. Wherein B is represented by the following general formula (a2). (However, Y is OCO- or O-, n is 0 ≦ n ≦ 3, R
³ is -C _d H _{2d + 1} when n = 0, and when 1 ≦ n ≦ 3
OC _d H _{2d + 1} , —CN or —Cl, wherein d is 0
≦ d ≦ 3. ) 3. A side-chain type liquid crystal polymer having a structural unit comprising the optically active monomer according to claim 1. 4. A copolymer comprising, as a component, a monomer forming a polymer exhibiting a nematic liquid crystal phase with the optically active monomer according to claim 2 and containing 1 to 40% by weight of the optically active monomer unit. And a liquid crystal polymer exhibiting a cholesteric liquid crystal phase. 5. A polymer having 1 to 40% by weight of the optically active monomer according to claim 2 as a total monomer component and 99 to 60% by weight of a polymer having a monomer forming a polymer exhibiting a nematic liquid crystal phase as a total monomer component. And a cholesteric liquid crystal phase. 6. An optical element comprising a solidified layer of a cholesteric liquid crystal phase having a Grandian orientation and comprising the liquid crystal polymer according to claim 3 and exhibiting circular dichroism. 7. The optical element according to claim 6, which exhibits circular dichroism with respect to light in a visible light region. 8. An optical element according to claim 6, wherein the optical element comprises a laminate of solidified layers of a liquid crystal polymer exhibiting circular dichroism with respect to light of different wavelengths. 9. An optical element according to claim 6, further comprising a retardation layer for converting circularly polarized light into linearly polarized light.