JP4655348B2 - Acrylic acid derivative compound, polymer liquid crystal obtained by polymerizing the same, and use thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an acrylic acid derivative compound, a polymer liquid crystal obtained by polymerizing the same, and an application.
[0002]
[Prior art]
A polymerizable liquid crystal monomer in which a polymerizable functional group is added to the liquid crystal monomer has both a property as a monomer and a property as a liquid crystal. Therefore, when the polymerizable liquid crystal monomer is polymerized in an aligned state, a polymer in which the alignment is fixed, that is, a polymer liquid crystal is obtained. The polymer liquid crystal thus obtained has optical anisotropy based on the refractive index anisotropy of the liquid crystalline skeleton, and can also impart special characteristics by controlling the liquid crystal alignment state, so that optical films such as retardation films and polarization holograms can be provided. Applied to devices.
Among such polymerizable liquid crystal monomers, in particular, a photopolymerizable liquid crystal monomer having a photopolymerizable functional group is an excellent material capable of easily producing a polymer liquid crystal by being irradiated with light and polymerized.
[0003]
A polarization hologram using this polymer liquid crystal exhibits high light utilization efficiency due to its polarization dependency, as described in JP-A-11-2111905. At this time, assuming that the grating height is d, the refractive index anisotropy of the polymer liquid crystal is Δn, and the wavelength is λ, ± 1st-order diffraction efficiency is maximized when λ / 2 = Δn · d is satisfied.
[0004]
In recent years, with the miniaturization of the optical head, the diffraction grating pitch p of the polarization hologram has been narrowed. However, when the grating is formed by photolithography, when the pitch becomes fine and the aspect ratio d / p of the grating becomes large, the deviation from the ideal grating shape becomes large, which causes a problem that the diffraction efficiency is lowered. Therefore, it is required to reduce the grating height d and the aspect ratio. That is, a polymer liquid crystal having a large refractive index anisotropy is desired.
[0005]
As such a polymer liquid crystal, one having a large refractive index anisotropy of Δn = 0.16 is known, as described in, for example, JP-A-9-208957. The polymer liquid crystal is composed of a composition of a compound represented by the following formula 2 or formula 3.
[0006]
[Chemical 2]
[0007]
By introducing a methylene group as a spacer into the molecule as in the liquid crystal monomer represented by Formula 3, the refractive index anisotropy of the polymer liquid crystal is increased. On the other hand, the temperature dependence of the refractive index anisotropy is increased. Also grows. When such a polymer liquid crystal is used for a polarization hologram, the diffraction efficiency varies greatly depending on the temperature, which causes a problem that stable reproduction cannot be performed.
In order to solve this problem, a method using a polymer liquid crystal obtained by polymerizing a composition containing a crosslinkable liquid crystal monomer is effective. As such a crosslinkable liquid crystal monomer, for example, a compound represented by the following formula 4 (Japanese Patent No. 2716451) is known.
[0008]
[Chemical 3]
(However, q = 2 to 11, and the code used here indicates only the code in this expression.)
[0009]
However, in order to further improve the refractive index anisotropy of the polymer liquid crystal, a crosslinkable liquid crystal monomer having a higher refractive index anisotropy is required.
[0010]
[Problems to be solved by the invention]
An object of the present invention is to firstly provide an acrylic acid derivative compound which is a crosslinkable liquid crystal monomer having a high refractive index anisotropy, and secondly, a polymer obtained by polymerizing a composition containing the same. The object is to provide a liquid crystal and its use.
[0011]
[Means for Solving the Problems]
The present invention provides an acrylic acid derivative compound represented by the following formula 1 (hereinafter also referred to as compound 1 and the same applies in other cases).
[0012]
[Formula 4]
The symbols in Formula 1 have the following meanings.
R ¹ , R ² : Each independently a hydrogen atom or a methyl group.
E ¹ , E ² : Each independently represents a 1,4-phenylene group, and one or more hydrogen atoms in the group may be substituted with a fluorine atom, a chlorine atom or a methyl group.
m, n: E ¹ , E ² Are both unsubstituted 1,4-phenylene groups, m and n are each independently an integer of 4 to 12, and E ¹ , E ² Is a 1,4-phenylene group, and one or more hydrogen atoms in at least one group are substituted, m and n are each independently an integer of 3 to 12.
In the above formula, it is particularly preferred that m = n.
[0013]
The present invention also uses a composition containing 10 to 90% by mass of one or more acrylic acid derivative compounds in the composition, a polymer liquid crystal obtained by polymerizing the composition, and the polymer liquid crystal. An optical element and an optical head using the optical element are provided.
The composition is preferably polymerized by irradiation with ultraviolet light or visible light.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
The acrylic acid derivative compound of the present invention is a generic term for compounds that are acrylic acid derivatives and compounds that are methacrylic acid derivatives. The same applies to expressions such as acryloyloxy groups.
The compound 1 of the present invention has an acryloyloxy group which is a photopolymerizable functional group at both ends, and the acryloyloxy group is bonded to the liquid crystal skeleton via an alkyleneoxy group. The liquid crystal skeleton has a skeleton in which a substituted or unsubstituted 1,4-phenylene group is bonded to a —C≡C— group, that is, a tolan group (or a derivative thereof). Anisotropy can be expressed.
[0015]
In formula 1, R ¹ , R ² Are each independently a hydrogen atom or a methyl group.
R ¹ , R ² It is preferable that is a hydrogen atom since the polymerization rate becomes fast. Also R ¹ , R ² Is a methyl group, it is preferable because it can suppress relaxation of the main chain skeleton.
[0016]
E ¹ , E ² Are each independently a 1,4-phenylene group, and one or more of the hydrogen atoms in the group may be substituted with a fluorine atom, a chlorine atom or a methyl group. E ¹ Is preferably a 1,4-phenylene group, and E ² Is preferably a 1,4-phenylene group or a 1,4-phenylene group in which one of the hydrogen atoms in the group is substituted with a methyl group. In general, E ¹ , E ² Is preferably a 1,4-phenylene group because it exhibits high birefringence anisotropy. On the other hand, E ² When one of the hydrogen atoms is substituted with a methyl group, a nematic phase appears at a low temperature, which is preferable. In this case, the substitution position of the methyl group is not particularly limited, but the β-position is more preferable than the following α-position since a composition containing this compound appears at a lower temperature than the nematic phase.
[0017]
[Chemical formula 5]
[0018]
E ¹ , E ² Are both unsubstituted 1,4-phenylene groups, m and n are each independently an integer of 4 to 12. If it is less than 4, the melting point becomes high, and if it exceeds 12, it is too long and the temperature dependency of the refractive index anisotropy becomes large. For example, a compound represented by the following formula (BULL. Soc. Chem. Fr. 1973, 2, 605) which is similar to the compound 1 of the present invention but does not have a spacer such as a methylene group between a tolan group and a side chain. Is not preferable because the melting point is 135 ° C., and the composition containing a compound having a high melting point causes a problem that the melting point becomes high.
[0019]
[Chemical 6]
[0020]
On the other hand, E ¹ , E ² Is a 1,4-phenylene group in which at least one hydrogen atom in at least one group is substituted, the melting point is low, and m and n are each independently an integer of 3 to 12. If it is less than 3, the spacer is too short, so that there is a problem that the refractive index anisotropy is greatly reduced during polymerization.
[0021]
A compound in which m = n, that is, an acrylic acid derivative compound represented by the following formula 5, formula 6 or formula 7 (hereinafter also referred to as compound 5, compound 6 or compound 7) is preferred in that the synthesis is simple. .
[0022]
[Chemical 7]
[0023]
As compound 5, compound 6 or compound 7, the following compounds are preferably exemplified. (However, Ph represents a 1,4-phenylene group, and Ph (CH _Three ) Shows both the case where a methyl group is substituted at the α-position and the case where a methyl group is substituted at the β-position. )
[0024]
[Chemical 8]
[0025]
Compound 5 can be synthesized, for example, by the method shown below.
[0026]
[Chemical 9]
(In the above formula, R ¹ , M is R in Formula 1 ¹ , M and R ¹ Compound 5 is obtained when is a hydrogen atom. )
[0027]
<First stage>
4,4′-dihydroxydiphenylacetylene (compound a) and n-bromoalcohol are mixed and dissolved in a solvent, and the reaction is carried out by heating under reflux in the presence of a base.
After completion of the reaction, the reaction product is purified to obtain 4,4′-bis (hydroxyalkoxy) diphenylacetylene (compound b).
[0028]
A base is not specifically limited, A well-known thing can be used. For example, potassium carbonate, potassium hydroxide and the like are suitable.
The solvent is easily soluble in 4,4′-dihydroxydiphenylacetylene and n-bromoalcohol, and is not particularly limited as long as it is inert to these. For example, dimethylformamide or ethanol is preferably used.
[0029]
<Second stage>
Next, the obtained compound b is dissolved in a solvent, and in the presence of a base, acrylic acid chloride is added dropwise and reacted at room temperature with sufficient stirring. In Equation 5, R ¹ When is a methyl group, methacrylic acid chloride may be used instead of acrylic acid chloride.
After completion of the reaction, the product is purified to obtain compound 5.
The base is not particularly limited, and a known one can be used. For example, N, N-dimethylaniline or triethylamine is preferably exemplified.
The solvent preferably dissolves the compound b, base and acrylic acid chloride and is inert. For example, N, N′-dimethyl-2-pyrrolidinone or tetrahydrofuran is preferably exemplified.
Compound 6 or 7 can also be obtained in the same manner by using the following compound c or compound d instead of compound a.
[0030]
Embedded image
[0031]
The method for synthesizing Compound 5, Compound 6 or Compound 7 is not limited to the above method, and can be obtained by other synthetic routes. For example, there is a method of reacting the compound a with 4-hydroxyalkyl acrylate in the presence of triphenylphosphine and diethyl azodicarboxylate.
When compound 1 is m ≠ n, the reaction may be performed using a compound in which one of the hydroxyl groups of compound a is protected. The protecting group is preferably a protecting group that is stable in the presence of a base, and more preferably a group that can be easily removed at room temperature. The protecting group is not particularly limited, and a known protecting group may be used, and examples thereof include a tetrahydropyranyl group and a benzyl group.
[0032]
When the compound 1 obtained as described above is used as a composition, one or more kinds of the compound 1 are used as other polymerizable liquid crystal compounds, polymerizable non-liquid crystal compounds, non-polymerizable liquid crystal compounds, non-polymerizable non-liquid crystal compounds. And a composition having desired characteristics. 10-90 mass% is preferable, and, as for the ratio in the composition of the compound 1, 20-80 mass% is especially preferable. If it is less than 10% by mass, the crosslinking effect is insufficient, and if it exceeds 90% by mass, cracks may occur during polymerization, so it is preferably used within the above range.
The other polymerizable liquid crystal compound is not particularly limited as long as it is a known compound having a liquid crystal skeleton and a polymerizable functional group. As the liquid crystal skeleton, those having at least two or three six-membered rings are preferable. Examples of other polymerizable liquid crystal compounds include polyester-based, polysiloxane-based, polyether-based, polymethacrylate-based, and polyacrylate-based compounds. Among these, polyacrylate or polymethacrylate compounds are particularly preferable because they have good photopolymerization characteristics.
[0033]
When other polymerizable liquid crystal compounds have a plurality of polymerizable functional groups, the types of the polymerizable functional groups may be different. Many compounds having two polymerizable functional groups are known, and when these are polymerized, generally good heat resistance and strength characteristics can be obtained, so that they are preferably used. Such a compound is preferably contained in the composition in an amount of 20 to 80% by mass.
Specifically, the following diacrylic acid compounds described in JP-A-10-265531 can be exemplified.
[0034]
Embedded image
(Where A ² Is a fluorine atom, a chlorine atom, a hydrogen atom or a methyl group, q is an integer of 0 to 8, r is 0 when q is 0 or 1, and q is an integer of 2 to 8 R is 1 and X ² Is a single bond, —COO—, —OCO— or —CH ₂ CH ₂ -, S is 0 or 1, p is 0 or 1, and X is 0. ^Three Is a single bond and X when p is 1 ^Three Is X ² Is the same structure. However, the code | symbol used here shall point out only the code | symbol in this type | formula. )
[0035]
The following compounds are particularly preferable.
[0036]
Embedded image
[0037]
Moreover, as a compound which has one polymeric functional group in a molecule | numerator, it is good to contain 20-80 mass% in a composition, and the compound represented by the following formula illustrated by the same gazette is mentioned.
[0038]
Embedded image
(Where A ¹ Is a fluorine atom, a chlorine atom, a hydrogen atom or a methyl group, m is an integer of 0-8, n is 0 when m is 0 or 1, and m is an integer of 2-8 N is 1 and X ¹ Is a single bond, —COO—, —OCO— or —CH ₂ CH ₂ -, Y is a 1,4-phenylene group or a 1,4-transcyclohexylene group, and Z ¹ Is an alkyl group having 1 to 8 carbon atoms, an alkoxyl group having 1 to 8 carbon atoms, a fluorine atom, a chlorine atom or a cyano group. However, the code | symbol used here shall point out only the code | symbol in this type | formula. )
[0039]
Among these, the following compounds are particularly preferable because of their large refractive index anisotropy.
[0040]
Embedded image
[0041]
Moreover, the compound shown by a following formula can also be illustrated.
[0042]
Embedded image
(Wherein R ^Three Is a hydrogen atom or a methyl group, R ^Four Is an alkyl group, E ^Three , E ^Four , E ^Five Are each independently a 1,4-phenylene group, and one or more hydrogen atoms in the group may be substituted with a fluorine atom, a chlorine atom or a methyl group. X and Y are each independently a single bond or an oxycarbonyl group, α is an integer of 0 to 8, β is 0 when α is 0, 1 when α is 1 or more, and γ represents 0 or 1. However, the code | symbol used here shall point out only the code | symbol in this type | formula. )
[0043]
Especially R ^Four Is preferably an alkyl group having 2 to 6 carbon atoms. For example, the following compounds are preferred.
[0044]
Embedded image
[0045]
Furthermore, the compound shown by a following formula can also be illustrated.
[0046]
Embedded image
Wherein Y is a 1,4-phenylene group or a 1,4-transcyclohexylene group; ² Represents an alkyl group having 1 to 8 carbon atoms. )
[0047]
Specifically, 4- (trans-4′-n-propylcyclohexylcarbonyloxy) phenyl acrylate, 4- (trans-4′-n-butylcyclohexylcarbonyloxy) phenyl acrylate, 4- (trans-4′-n) -Pentylcyclohexylcarbonyloxy) phenyl acrylate, 4- (4'-n-propylphenylcarbonyloxy) phenyl acrylate, 4- (4'-n-butylphenylcarbonyloxy) phenyl acrylate, 4- (4'-n-pentyl) Preferred examples include phenylcarbonyloxy) phenyl acrylate.
These polymerizable liquid crystal compounds can be used alone or in combination of two or more.
[0048]
The composition of the present invention may also contain a polymerizable non-liquid crystal compound, that is, a polymerizable compound that does not exhibit liquid crystallinity. Such a polymerizable compound is not particularly limited, but acrylate-based, methacrylate-based, and vinyl ether-based compounds are particularly preferable, and these can be used alone or in combination of two or more.
[0049]
Furthermore, the composition of the present invention can contain a non-polymerizable liquid crystal compound, that is, a liquid crystal compound having no polymerizable functional group. Such a liquid crystal compound is not particularly limited as long as it is a known liquid crystal compound, such as a component exhibiting liquid crystallinity at a low temperature, a low viscosity component, a component that improves dielectric anisotropy, and a component that imparts cholesteric properties. These can be selected appropriately according to the required performance. These may be used singly or in combination of two or more, and are preferably contained in a ratio that can impart desired characteristics.
[0050]
Examples thereof include compounds represented by the following formulas described in JP-A-9-180234 and JP-A-9-281332.
[0051]
Embedded image
(In the formula, A is a phenylene group or trans-1,4-cyclohexylene group, m is 0 or 1, X is a fluorine atom or a hydrogen atom, Y is a cyano group, a fluorine atom or a chlorine atom, and Z is a fluorine atom or A hydrogen atom and R are a linear alkyl group having 2 to 8 carbon atoms or a linear alkoxyl group having 2 to 8 carbon atoms, provided that the symbols used here refer only to the symbols in this formula. .)
[0052]
In particular, for the purpose of reducing the viscosity, for example, a dialkenyl biphenyl derivative having an alkenyl group at both ends of biphenyl described in JP-A-9-328443 is effective, and such a compound increases the clearing point. Since there is an effect and the refractive index anisotropy is relatively large, it can be preferably used.
Japanese Patent Application Laid-Open No. 10-36847 exemplifies compounds having the following structures as a viscosity reducing agent, a NI (nematic phase-isotropic phase transition) point adjusting agent, or a freezing point adjusting agent.
[0053]
Embedded image
(In the formula, R represents an alkyl group or an alkoxy group, X represents a hydrogen atom, a methyl group, a halogen atom, a cyano group, a phenyl group, etc., and n represents a positive number. (It shall refer only to the sign in this formula.)
Further, compounds having the following structure described in JP-A-10-228670 can also be used.
[0054]
Embedded image
(Wherein R _Five , R ₆ And R ₇ Represents an alkyl group or an alkoxyl group, and m represents an integer of 0 or 1. However, the code | symbol used here shall point out only the code | symbol in this type | formula. )
[0055]
Moreover, as a compound which improves dielectric anisotropy, the compound of the following structure etc. which are described in Unexamined-Japanese-Patent No. 10-067694 etc. are mentioned, for example.
[0056]
Embedded image
(Wherein R _Four And R _Five Each independently represents an alkyl group having 1 to 10 carbon atoms, but any non-adjacent methylene group in the group may be substituted with an oxygen atom or —CH═CH—. Any hydrogen atom in the group may be substituted with a fluorine atom. Y ₂ Represents a —CN group or —C≡C—CN. Ring F represents trans-1,4-cyclohexylene, 1,4-phenylene, 1,3-dioxane-2,5-diyl or pyrimidine-2,5-diyl, and ring G represents trans-1,4-cyclohexyl. Silene, 1,4-phenylene or pyrimidine-2,5-diyl in which a hydrogen atom may be substituted with a fluorine atom, and ring M represents trans-1,4-cyclohexylene or 1,4-phenylene. Z ₆ Represents a 1,2-ethylene group, —COO— or a covalent bond. L _Three , L _Four And L _Five Each independently represents a hydrogen atom or a fluorine atom. b, c and d each independently represent 0 or 1; Moreover, the atom used in each formula is shown also including an isotope. However, the code | symbol used here shall point out only the code | symbol in this type | formula. )
[0057]
The composition of the present invention is preferably prepared so as to exhibit a liquid crystal phase in a temperature range of −30 to 150 ° C., more preferably −10 to 120 ° C., and preferably exhibits a liquid crystal phase in a wider temperature range.
[0058]
The composition of the present invention can also be imparted with cholesteric properties by adding a chiral compound. It does not specifically limit as a chiral compound, For example, what has a cholesteryl group as optically active groups, such as pelargonic acid cholesterol or a stearic acid cholesterol, CB-15, C-15 (made by BDH), S-1082 in a commercial item. S-811 (manufactured by Merck), CM-21, CM-22 (manufactured by Chisso), and the like, those having a 2-methylbutyl group as the optically active group can be preferably used. These may be used alone or in combination of two or more.
[0059]
Furthermore, a stabilizer may be added to the composition of the present invention in order to improve its storage stability. Examples of the stabilizer include hydroquinone, hydroquinone monoalkyl ethers and tert-butylcatechols.
[0060]
The composition of the present invention thus prepared forms a polymer liquid crystal by photopolymerization. At this time, glass, plastic or the like can be used as the support. The support surface may be subjected to orientation treatment as necessary. In the orientation treatment, the support surface may be directly rubbed with natural fibers such as cotton and wool, synthetic fibers such as nylon and polyester, or polyimide or polyamide may be applied and the surface may be rubbed with the above fibers or the like. Good. Spacers such as glass beads are arranged, a plurality of supports are opposed to each other at a desired interval, and the composition is injected and filled between the supports. The injected composition is maintained in a liquid crystal state and photopolymerized in a state where molecules are aligned.
[0061]
In order to keep the composition in a liquid crystal state, the ambient temperature is changed to the melting point T _m To nematic isotropic phase transition temperature T _c The range of T _c Since the refractive index anisotropy is extremely small at temperatures close to, the upper limit of the ambient temperature is (T _c -10) It is preferable to set it as below degrees C The light used for photopolymerization is preferably ultraviolet light or visible light.
In the case of photopolymerization, it can be efficiently polymerized by using a photopolymerization initiator. The photopolymerization initiator is not particularly limited, and photopolymerization initiators such as acetophenones, benzophenones, benzoins, benzyls, Michler ketones, benzoin alkyl ethers, benzyl dimethyl ketals, and thioxanthones can be preferably used. Moreover, you may mix and use 2 or more types of photoinitiators as needed. 0.1-10 mass% is preferable with respect to a composition, and, as for the usage-amount of a photoinitiator, 0.3-2 mass% is especially preferable.
[0062]
The polymer liquid crystal of the present invention may be used while being sandwiched between supports, or may be used after being peeled off from the support. The polymer liquid crystal thus produced has a high refractive index anisotropy and is suitable for an optical element since it has liquid crystallinity in a temperature range wider than that of the monomer liquid crystal before polymerization.
[0063]
Among such optical elements, it is suitable as a polymer film having uniaxial anisotropy, and examples thereof include a retardation film, a polarizing prism, and a polarizing hologram. It is particularly suitable as a polarization hologram, and this will be described below.
The polarization hologram has a function of changing the diffraction efficiency with respect to different polarized light by having a grating structure periodically modulated in refractive index. In particular, the case where the diffraction efficiency ratio of the 0th order and the ± 1st order is maximized is preferably used for S-polarized light and P-polarized light having different polarization directions by 90 degrees. Further, when an optical element is used, it is often used in combination with a quarter-wave plate in order to control the polarization direction. As such an example, a polarization hologram beam splitter with high reciprocating efficiency used as an optical pickup. Is mentioned.
[0064]
In the case of using a polymer liquid crystal as a polarization hologram, a method for producing a refractive index-modulated grating structure is to use a substrate having a transparent electrode such as ITO patterned on a periodic basis to bring it into a predetermined alignment state in a monomer state. After control, the polymer liquid crystal is polymerized by periodically refractive index modulation, or as described in JP-A-11-2111905, the monomer is uniaxially oriented and polymerized to obtain a uniaxially oriented high liquid crystal. Examples of the method include a method in which after forming a molecular liquid crystal, a lattice shape is imparted by photolithography, and an isotropic medium is filled in a lattice concave portion.
Alternatively, the polarization hologram may be manufactured by performing the alignment process on the two opposing substrates and then performing the mold release process on the opposing surface of at least one of the substrates.
Furthermore, as a method for producing a polarization hologram, a method of filling a composition into a concave portion of an isotropic substrate having a lattice shape and then polymerizing it into a polarization hologram can be exemplified. At the time of filling, it is preferable to use a substrate that has been subjected to a rubbing treatment because there is little alignment disorder. The filling method can be the same as that of the above-mentioned JP-A No. 11-21905. In addition, the substrate having no opposing lattice shape is subjected to an alignment treatment, and then subjected to a mold release treatment, and after the polymerization, the counter substrate. The polarization hologram may be manufactured by peeling off.
[0065]
Next, FIG. 1 shows a schematic side view when the above-described polarization hologram is used as an optical head device as a hologram beam splitter. In FIG. 1, the light emitted from the semiconductor laser 5 as the light source passes through the polarization hologram 4 as the hologram beam splitter, is condensed on the optical disk 8 by the objective lens 7, and the reflected light from the optical disk 8 is again the objective lens 7. , And is diffracted by the hologram beam splitter and reaches the light receiving element 6.
By inserting the quarter wavelength plate 10 between the hologram beam splitter and the optical disk 8, the polarization direction of the linearly polarized light emitted from the semiconductor laser 5 can be rotated by 90 degrees in the forward path and the backward path, The transmittance is high for the light in the forward polarization direction, and the diffraction efficiency is high for the light in the polarization direction of the return path, so that the light utilization efficiency can be increased.
[0066]
【Example】
Hereinafter, the present invention will be described more specifically with reference to examples.
[Example 1: Synthesis of Compound 5A]
Compound 5A represented by the following formula was synthesized.
[0067]
Embedded image
[0068]
4,4′-dihydroxydiphenylacetylene (compound a) 15 g (0.070 mol), 6-bromo-1-heptanol 38.8 g (0.21 mol), potassium carbonate 39 g (0.29 mol) and dimethylformamide 150 mL of the mixture was refluxed at 125 ° C. After sufficiently reacting, the reaction solution was added to ice water and filtered under reduced pressure to collect crystals. This was washed with 1 mol / L HCl and water and dried. Thereafter, recrystallization is carried out using dioxane and a mixed solvent of dioxane / toluene to obtain powder crystals 17 of 4,4′-bis (6-hydroxyheptyloxy) -diphenylacetylene (a compound represented by m = 6 in the formula b). 0.6 g was obtained (yield 60%).
[0069]
Next, 11.7 g (0.030 mol) of the obtained powder crystal was dissolved in 57.2 g (0.47 mol) of dimethylaniline and 150 mL of N, N′-dimethyl-2-pyrrolidinone, and N, N′— 10.3 g (0.11 mol) of acrylic acid chloride dissolved in 20 mL of dimethyl-2-pyrrolidinone was added dropwise. After sufficiently reacting at room temperature, the reaction solution was added to ice water, and the organic phase was extracted. Hexane was added thereto, and the precipitate was collected by vacuum filtration. This was dissolved in methylene chloride (solvent), washed with 0.5 mol / L NaOH and water, and dried over anhydrous magnesium sulfate. The solvent was concentrated under reduced pressure, and the resulting crystals were recrystallized using a hexane / toluene mixed solvent. Further, column chromatography was performed using a column packed with silica gel using a mixed solvent of hexane and ethyl acetate as a developing solvent. The extract was purified and recrystallized with a hexane / toluene mixed solvent to obtain 7.65 g (yield 52%) of compound 5A, that is, 4,4′-bis (6-acryloyloxyheptyloxy) diphenylacetylene powder crystal. Obtained.
[0070]
The infrared absorption spectrum (KBr tablet) of compound 5A is shown in FIG.
Also, ¹ H-NMR spectrum (CDCl _Three Solvent, TMS internal standard) is δ (ppm): 1.3-1.5 (8H, m), 1.64 (4H, m), 1.72 (4H, m), 3.99 (4H, t), 4.11 (4H, t), 5.93 (2H, d), 6.17 (2H, dd), 6.31 (2H, d), 6.94 (4H, d), 7. 43 (4H, d).
[0071]
As a result of observing Compound 5A under a polarizing microscope, it changed from a crystal to an isotropic liquid at 68 ° C. when the temperature was raised. Since the phase transition from an isotropic liquid to a smectic A phase at 68 ° C. and a crystal at 57 ° C. during cooling, it was confirmed to be a monotropic liquid crystal.
[0072]
[Example 2: Synthesis of Compound 5B]
Instead of 6-bromo-1-heptanol used in Example 1, 8-bromo-1-octanol was used. Otherwise in the same manner as in Example 1, the following compound 5B was obtained.
[0073]
Embedded image
[0074]
The infrared absorption spectrum (KBr tablet) of compound 5B is shown in FIG.
Also, ¹ H-NMR spectrum (CDCl _Three Solvent, TMS internal standard) is δ (ppm): 1.3-1.5 (16H, m), 1.67 (4H, m), 1.78 (4H, m), 3.96 (4H, t), 4.15 (4H, t), 5.82 (2H, d), 6.12 (2H, dd), 6.39 (2H, d), 6.84 (4H, d), 7. 42 (4H, d).
As a result of observing compound 5B under a polarizing microscope, it changed from a crystal to an isotropic liquid at 75 ° C. when the temperature was raised. Since the phase transition from an isotropic liquid to a smectic A phase at 75 ° C. and a crystal at 70 ° C. at the time of temperature decrease, it was confirmed to be a monotropic liquid crystal.
[0075]
[Example 3: Synthesis of Compound 5C]
The following compound 5C was synthesized as follows.
[0076]
Embedded image
[0077]
1.00 g (0.0048 mol) of 4,4′-dihydroxydiphenylacetylene, 20 mL of dry tetrahydrofuran, 1.65 g (0.011 mol) of 4-hydroxybutyl acrylate, 2.99 (0.011 mol) of triphenylphosphine The mixture of 1.99 g (0.11 mol) of diethyl azodicarboxylate and 10 mL of dry tetrahydrofuran was added thereto and reacted at room temperature. After sufficiently reacting, tetrahydrofuran was distilled off to obtain a brown liquid. This was subjected to column chromatography using a column packed with silica gel using dichloromethane as a developing solution. The extract was purified and recrystallized from ethanol to obtain 1.10 g (yield 50%) of compound 5C, ie, 4,4′-bis (4-acryloyloxybutyloxy) diphenylacetylene powder crystals.
[0078]
The infrared absorption spectrum (KBr tablet) of compound 5C is shown in FIG.
Also, ¹ H-NMR spectrum (CDCl _Three Solvent, TMS internal standard) is δ (ppm): 1.89 (8H, m), 4.01 (4H, t), 4.24 (4H, t), 5.83 (2H, d), 6 .12 (2H, dd), 6.41 (2H, d), 6.85 (4H, d), and 7.43 (4H, d).
As a result of observing Compound 5C under a polarizing microscope, it changed from a crystal to an isotropic liquid at 80 ° C. when the temperature was raised. When the temperature was lowered, a phase transition from an isotropic liquid to a crystal occurred at 79 ° C., and no liquid crystal phase was observed.
[0079]
[Example 4: Synthesis of Compound 6A]
Instead of 4,4′-dihydroxydiphenylacetylene (compound a) used in Example 1, 4,4′-dihydroxy-3-methyldiphenylacetylene (compound c) was used. Otherwise in the same manner as in Example 1, the following compound 6A was obtained.
[0080]
Embedded image
[0081]
The infrared absorption spectrum (KBr tablet) of Compound 6A is shown in FIG.
Also, ¹ H-NMR spectrum (CDCl _Three Solvent, TMS internal standard) is δ (ppm): 1.3 to 1.6 (8H, m), 1.6 to 1.9 (8H, m), 2.20 (3H, s), 3. 97 (4H, t), 4.17 (4H, t), 5.81 (2H, d), 6.12 (2H, dd), 6.40 (2H, d), 6.75 (1H, d) ), 6.84 (2H, d), 7.23 (1H, s), 7.3 (1H, d), and 7.42 (2H, d).
As a result of observing compound 6A under a polarizing microscope, it changed from a crystal to an isotropic liquid at 43 ° C. when the temperature was raised. Since the phase transition from an isotropic liquid to a nematic phase at 32 ° C. and a crystal at 30 ° C. at the time of cooling, it was confirmed to be a monotropic liquid crystal.
[0082]
[Example 5: Synthesis of Compound 6B]
Instead of 4,4′-dihydroxydiphenylacetylene (the compound a) used in Example 3, 4,4′-dihydroxy-3-methyldiphenylacetylene (the compound c) was used. Otherwise in the same manner as in Example 3, the following compound 6B was obtained.
[0083]
Embedded image
The infrared absorption spectrum (KBr tablet) of compound 6B is shown in FIG.
Also, ¹ H-NMR spectrum (CDCl _Three Solvent, TMS internal standard) is δ (ppm): 1.9 to 2.0 (8H, m), 2.21 (3H, s), 4.01 (4H, t), 4.25 (4H, t), 5.83 (2H, d), 6.12 (2H, dd), 6.41 (2H, d), 6.75 (1H, d), 6.84 (2H, d), 7. 26 (1H, s), 7.3 (1H, d), and 7.42 (2H, d).
As a result of observing Compound 6B under a polarizing microscope, it changed from a crystal to an isotropic liquid at 50 ° C. when the temperature was raised. When the temperature was lowered, the phase was changed from an isotropic liquid to a crystal at 43 ° C., and no liquid crystal phase was observed.
[0084]
Example 6 Synthesis of Compound 6C
Instead of 4,4′-dihydroxydiphenylacetylene (compound a) used in Example 1, 4,4′-dihydroxy-3-methyldiphenylacetylene (compound c) was used instead of 6-bromo-1-heptanol. 3-Bromo-1-propanol was used. Otherwise in the same manner as in Example 1, the following compound 6C was obtained.
[0085]
Embedded image
The infrared absorption spectrum (KBr tablet) of Compound 6C is shown in FIG.
Also, ¹ H-NMR spectrum (CDCl _Three Solvent, TMS internal standard) is δ (ppm): 2.1-2.2 (4H, m), 2.21 (3H, s), 4.08 (4H, t), 4.37 (4H, t), 5.84 (2H, d), 6.13 (2H, dd), 6.41 (2H, d), 6.76 (1H, d), 6.85 (2H, d), 7. 26 (1H, s), 7.32 (1H, d), and 7.43 (2H, d).
As a result of observing Compound 6C under a polarizing microscope, it changed from a crystal to an isotropic liquid at 71 ° C. when the temperature was raised. When the temperature was lowered, the phase was changed from an isotropic liquid to a crystal at 45 ° C., and no liquid crystal phase was observed.
[0086]
[Example 7: Synthesis of Compound 7A]
In place of 4,4′-dihydroxydiphenylacetylene (the compound a) used in Example 1, 4,4′-dihydroxy-2-methyldiphenylacetylene (the compound d) was used. Otherwise in the same manner as in Example 1, the following compound 7A was obtained.
[0087]
Embedded image
[0088]
The infrared absorption spectrum (KBr tablet) of Compound 7A is shown in FIG.
Also, ¹ H-NMR spectrum (CDCl _Three Solvent, TMS internal standard) is δ (ppm): 1.3-1.6 (8H, m), 1.6-1.9 (8H, m), 2.45 (3H, s), 3. 97 (4H, t), 4.17 (4H, t), 5.82 (2H, d), 6.12 (2H, dd), 6.40 (2H, d), 6.65 (1H, d) ), 6.75 (1H, s), 6.85 (2H, d), 7.38 (1H, d), and 7.42 (2H, d).
As a result of observing Compound 7A under a polarizing microscope, it changed from a crystal to an isotropic liquid at 78 ° C. when the temperature was raised. When the temperature was lowered, a phase transition from an isotropic liquid to a crystal occurred at 62 ° C., and no liquid crystal phase was observed.
[0089]
[Example 8: Refractive index anisotropy of compound 5A]
Clear point T _c Is 85 ° C., and the temperature T obtained by Equation 8 _s Refractive index anisotropy Δn (X ₀ ) _Ts Liquid crystal monomer X with 0.119 _o Was used. The refractive index anisotropy of the composition was determined at 589 nm. Liquid crystal monomer X _o In which 10 mol% of compound 5A was dissolved in ₁ Was prepared. This composition X ₁ T _c Is 82 ° C., and the temperature T determined by Equation 8 is _s Composition X measured in ₁ Refractive index anisotropy Δn (X ₁ ) _Ts Was 0.126. Here, the refractive index anisotropy Δn calculated by Equation 9 _Ts Is defined as the refractive index anisotropy of compound 5A. △ n (X ₀ ) _Ts And Δn (X ₁ ) _Ts Is substituted into Equation 9 and the calculated refractive index anisotropy Δn of compound 5A _Ts Was 0.243.
[0090]
[Expression 1]
[0091]
[Example 9: Refractive index anisotropy of compounds 5B, 5C, 6A, and 7A]
Refractive index anisotropy Δn of compounds 5B, 5C, 6A and 7A in the same manner as in Example 8. _Ts Were 0.219, 0.253, 0.217, and 0.233, respectively.
[0092]
[Example 10: Refractive index anisotropy of compound e]
Refractive index anisotropy Δn of a compound in which q is 6 in formula 4, that is, 4,4′-bis (acryloyloxyhexyloxy) biphenyl (hereinafter referred to as compound e). _Ts Was obtained in the same manner as in Example 6, and was found to be 0.150. The compound changed from a crystal to an isotropic liquid at 81 ° C. when the temperature was increased. Even when the temperature was lowered, the crystal changed from an isotropic liquid to a crystal at 81 ° C., and no liquid crystal phase was observed.
[0093]
Table 1 shows the refractive index anisotropy of the compounds 5A, 5B, 5C, 6A, and 7A and the compound e.
[0094]
[Table 1]
[0095]
Example 11: Preparation of composition
4-acryloyloxy-4′-cyanobiphenyl (the following compound X ₁ ), 4- (3-acryloyloxypropyl) oxy-4′-cyanobiphenyl (compound X below) ₂ ), 4- (6-acryloyloxyhexyl) oxy-4′-cyanobiphenyl (the following compound X) _Three ), 4- (4-n-butylbenzoyloxy) phenyl acrylate (compound X below) _Four ), 4- (4-n-hexylbenzoyloxy) phenyl acrylate (compound X below) _Five ) Using the composition Y ₁ Was prepared. The composition ratio is X in terms of molar ratio. ₁ : X ₂ : X _Three : X _Four : X _Five = 0.25: 0.10: 0.35: 0.15: 0.15.
[0096]
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[0097]
This composition Y ₁ Compound 5A is added to the composition Y so that the composition ratio is 25 mol%. ₂ Was prepared. Composition Y ₂ Is T _c Was a nematic liquid crystal having a temperature of 63 ° C. and being in a supercooled state but stable to room temperature. Also, composition Y ₂ The refractive index anisotropy at 40 ° C. was 0.181 at 589 nm.
[0098]
[Example 12: Production of polymer liquid crystal]
After applying polyimide, which is an alignment agent, with a spin coater and heat-treating, a glass substrate that has been rubbed in a certain direction with nylon cloth is used as a support, and the two supports are used with an adhesive so that the aligned surfaces face each other. The cell 1 was produced by bonding. At that time, a glass block was inserted on one side to form a wedge shape.
[0099]
Composition Y of Example 11 ₂ A photopolymerization initiator “Irgacure 907 (manufactured by Ciba Geigy)” was added to cell 1 at 70 ° C. Next, 5 mW / cm at 50 ° C. ² The polymer liquid crystal was produced by irradiating ultraviolet rays having the intensity of 300 nm for 300 seconds to carry out photopolymerization. This polymer liquid crystal was horizontally aligned in the rubbing direction of the substrate, and the refractive index anisotropy was 0.159 at 589 nm and 25 ° C. This polymer liquid crystal was transparent in the visible range, and no scattering was observed. The polymer liquid crystal exhibited refractive index anisotropy at room temperature or lower and 135 ° C. or higher, and had a wide liquid crystal temperature range.
[0100]
[Example 13: Refractive index anisotropy of polymer liquid crystal containing compound e]
Y prepared in Example 9 ₁ Compound e is added as a crosslinkable monomer to composition Y so that the composition ratio is 25 mol%. _Three Was prepared. Composition Y _Three Is T _c Was 61 ° C., and it was a nematic liquid crystal that was in a supercooled state but stable to room temperature. This composition Y _Three The refractive index anisotropy at 40 ° C. was 0.168 at 589 nm.
Next, composition Y _Three A photopolymerization initiator “Irgacure 907 (manufactured by Ciba Geigy)” was added to the same cell 1 as in Example 10 at 70 ° C. Next, 5 mW / cm at 50 ° C. ² A polymer liquid crystal was produced by irradiating with UV light having an intensity of 300 seconds for photopolymerization. The refractive index anisotropy of the polymer liquid crystal was 0.144 at 589 nm at 25 ° C.
[0101]
Composition Y comprising Compound 5A of the present invention ₂ And a composition Y comprising compound e _Three Table 2 compares the refractive index anisotropy after composition preparation and the refractive index anisotropy after polymerization of the composition.
[0102]
[Table 2]
[0103]
As shown in Table 2, by using the compound 5A of the present invention, high refractive index anisotropy could be imparted without lowering the nematic phase temperature range.
[0104]
[Example 14: Comparison of compositions containing compounds 5A, 6A, 7A]
Compound X above ₁ , X _Three And Compound 5A, the molar ratio is X ₁ : X _Three : Composition Y so that compound 5A = 0.35: 0.35: 0.3 _Four Was prepared.
Composition Y _Four Wherein the compound 6A was used instead of the compound 5A _Five And using compound 7A instead of compound 5A, Y ₆ Was prepared. Y _Four , Y _Five , Y ₆ Table 3 shows the liquid crystal temperature range.
[0105]
[Table 3]
[0106]
As shown in Table 3, when compounds 6A and 7A are used, smectic (S _m ) Phase does not develop, nematic (N _m ) Phase appeared. In particular, composition Y using compound 6A _Five Was a nematic phase stable to room temperature or below.
[0107]
[Example 15: Application to optical element and optical head]
On the surface of a glass substrate on which a rectangular grid having a pitch of 6 μm and a depth of 2 μm was formed, polyimide as an aligning agent was applied with a spin coater, heat-treated, and then rubbed in a direction parallel to the grid direction with a nylon cloth. A cell flat plate substrate having been subjected to the alignment treatment in the same manner was bonded using an adhesive so that the alignment treatment surfaces face each other, thereby producing a cell 2. At that time, the alignment directions were made parallel.
[0108]
Composition Y of Example 11 ₂ A photopolymerization initiator “Irgacure 907 (manufactured by Ciba Geigy)” added at 0.25 mass% was poured into the cell 2 produced as described above at 70 ° C. to fill the lattice-shaped recesses. Next, 5 mW / cm at 50 ° C. ² The photopolymerization was carried out by irradiating ultraviolet rays having the intensity of 300 seconds. A quarter wavelength plate was laminated on one side of the cell 2 to produce a polarization hologram beam splitter (optical element). When this polarization hologram splitter was used as an optical head component, the optical head obtained a light use efficiency of 50% in total of ± first-order diffraction efficiencies with a laser light source having a wavelength of 650 nm.
[0109]
【The invention's effect】
According to the present invention, an acrylic acid derivative compound which is a crosslinkable liquid crystal monomer having a high refractive index anisotropy can be synthesized. Compositions using this and polymer liquid crystals obtained by photopolymerization have high refractive index anisotropy. This polymer liquid crystal is suitable as a material for optical elements such as retardation films and polarization hologram elements. In particular, the polarization hologram element is suitable as a component such as an optical head.
The present invention can be applied in various ways as long as the effects of the present invention are not impaired.
[Brief description of the drawings]
FIG. 1 is a schematic side view of an optical head device of the present invention.
FIG. 2 is an infrared absorption spectrum of compound 5A.
FIG. 3 is an infrared absorption spectrum of compound 5B.
FIG. 4 is an infrared absorption spectrum of compound 5C.
FIG. 5 is an infrared absorption spectrum diagram of Compound 6A.
FIG. 6 is an infrared absorption spectrum of compound 6B.
FIG. 7 is an infrared absorption spectrum of compound 6C.
FIG. 8 is an infrared absorption spectrum of compound 7A.
[Explanation of symbols]
4 Polarization hologram
5 Semiconductor laser
6 Light receiving element
7 Objective lens
8 Optical disc
10 1/4 wave plate

Claims (8)

An acrylic acid derivative compound represented by the following formula 1.
The symbols in Formula 1 have the following meanings.
R ¹ and R ² : each independently a hydrogen atom or a methyl group.
E ^1, E ^2: each independently, an unsubstituted 1,4-phenylene group.
m, n: m, n are each independently 4-12 integer.   2. The acrylic acid derivative compound according to claim 1, wherein m = n.   The composition which contains 10-90 mass% of 1 or more types of the acrylic acid derivative compound of Claim 1 or 2 in a composition.   A polymer liquid crystal obtained by polymerizing the composition according to claim 3.   The polymer liquid crystal according to claim 4, which is polymerized by irradiation with ultraviolet rays or visible rays.   An optical element comprising the polymer liquid crystal according to claim 4 or 5.   An optical head using the optical element according to claim 6.   4,4′-bis (hydroxyalkoxy) diphenylacetylene is obtained by reacting 4,4′-dihydroxydiphenylacetylene with n-bromoalcohol in the presence of a base to obtain 4,4′-bis (hydroxyalkoxy) diphenylacetylene. By reacting with acrylic acid chloride in the presence of a base, or
  The acrylic acid derivative compound according to claim 1 or 2 is produced by reacting 4,4'-dihydroxydiphenylacetylene and 4-hydroxyalkyl acrylate in the presence of triphenylphosphine and diethyl azodicarboxylate. A method for producing an acid derivative compound.