JPWO2009028576A1 - Polymer liquid crystal, optically anisotropic film, and optical element - Google Patents

Abstract

A polymer liquid crystal capable of forming an optically anisotropic film having high transparency and excellent light resistance to blue laser light is provided. A polymer liquid crystal containing two or more types of monomer units derived from the monomer represented by the following formula (1), which is obtained by removing impurities by purification after polymerization. R1: a hydrogen atom or a methyl group. R2: An alkyl group, an alkoxy group, or a fluorine atom. E1, E2, E3, E4: each independently 1,4-phenylene group or trans-1,4-cyclohexylene group. m: An integer of 0-6. r: an integer of 0-6. n: An integer of 0-6. However, when r = 0, m + n is an integer of 10 or less. t: 0 (when m + r + n = 0) or 1 (when m + r + n> 0). h: 0 or 1. k: 0 or 1. CH2 = CR1-COO- (CH2) m- (CF2) r- (CH2) n- (O) t-E1- (E2) h- (E3) k-E4-R2 (1)

Description

  The present invention relates to a polymer liquid crystal, a method for producing an optical anisotropic film using the polymer liquid crystal, an optical anisotropic film, and an optical element having the optical anisotropic film.

In recent years, in order to increase the capacity of optical discs, the laser light used for writing and reading information has been shortened, and the use of laser light with a wavelength of 300 to 450 nm is being considered for next-generation recording media. Yes. Along with this, optical elements such as a diffraction element and a phase difference plate that modulate laser light having a wavelength of 300 to 450 nm (hereinafter referred to as blue laser light) are required. Therefore, an optical film used as such an optical element is required to have high transparency, high light resistance against blue laser light, and small change in characteristics due to temperature.
An optical film in which a liquid crystal compound is three-dimensionally controlled on a substrate has high birefringence, so that it can be made thinner than an optical film formed from a biaxially stretched polymer, and the angle dependency of incident light is small. There is.

As a general method for producing an optical film using a liquid crystal compound, a composition containing a liquid crystal monomer and a polymerization initiator is injected into a glass cell with an alignment film, and then polymerized and cured by ultraviolet irradiation in a temperature range showing a liquid crystal phase. And a method of forming a polymer liquid crystal is known (see Patent Document 1).
On the other hand, a method is known in which a polymer liquid crystal obtained by preliminarily polymerizing is sandwiched between two substrates with an alignment film and heat-treated to obtain an optical film (see Patent Document 2). In addition, it is also known that a uniaxially oriented film can be obtained by forming a polymer liquid crystal by a solution casting method and performing a heat treatment (see Patent Document 3).

International Publication No. 2006/001096 Pamphlet Japanese Patent Laid-Open No. 4-16916 JP 2004-77719 A

However, in the method described in Patent Document 1, an unreacted polymerization initiator, a decomposition product of the polymerization initiator, and an unreacted monomer are present in the polymer liquid crystal in the cell. This causes the polymer liquid crystal to deteriorate when irradiated with blue laser light, which causes the characteristics to deteriorate. Therefore, the optical film produced by this method may have poor light resistance against blue laser light.
In addition, the polymer liquid crystals disclosed in Patent Documents 2 and 3 have absorption in the blue wavelength region, and thus have a problem of poor light resistance against blue laser light.
Therefore, an object of the present invention is to provide a polymer liquid crystal that can form an optically anisotropic film having high transparency and excellent light resistance to blue laser light.

  The present invention relates to a polymer liquid crystal that has solved the above problems, a method for producing the polymer liquid crystal, an optically anisotropic film in which the polymer liquid crystal is aligned, a method for producing the same, and an optical element having the optically anisotropic film. This is the following invention.

<1> A polymer liquid crystal composed of a copolymer containing two or more types of monomer units derived from the monomer represented by the following formula (1) and obtained by removing impurities by purification after polymerization.
CH ₂ = CR ¹ -COO- (CH ₂ ) _m- (CF ₂ ) _r- (CH ₂ ) _n- (O) _t -E ^1- (E ² ) _h- (E ³ ) _k -E ⁴ -R ² (1)
However, the symbols in the formula are as follows.
R ¹ : a hydrogen atom or a methyl group.
R ² : an alkyl group which may be substituted with a fluorine atom having 1 to 8 carbon atoms, an alkoxy group which may be substituted with a fluorine atom having 1 to 8 carbon atoms, or a fluorine atom.
E ¹ , E ² , E ³ , E ⁴ : each independently a 1,4-phenylene group or a trans-1,4-cyclohexylene group, and a hydrogen atom bonded to a carbon atom in the group is a carbon number It may be substituted with an alkyl group of 1 to 10, an alkoxy group of 1 to 10 carbon atoms, or a fluorine atom.
m: An integer of 0-6.
r: an integer of 0-6.
n: An integer of 0-6.
However, when r = 0, m + n is an integer of 10 or less.
t: 0 (when m + r + n = 0) or 1 (when m + r + n> 0).
h: 0 or 1.
k: 0 or 1.

<2> The polymer liquid crystal according to <1>, wherein the copolymer has a number average molecular weight of 3,000 to 50,000 and a content of impurities having a number average molecular weight of 1,000 or less is less than 0.5% by mass. .
<3> The copolymer comprises at least one monomer unit derived from a monomer having h + k of 1 in formula (1) and at least one monomer unit derived from a monomer having h + k of 2 in formula (1). The polymer liquid crystal according to the above <1> or <2>.
<4> The polymer liquid crystal according to any one of <1> to <3>, wherein the copolymer has a glass transition point.
<5> After copolymerizing two or more of the monomers represented by the above formula (1), impurities are removed, and the copolymer has a number average molecular weight of 3,000 to 50,000 and a number average molecular weight of 1,000. After obtaining a polymer liquid crystal in which the content of the following impurities is less than 1% by mass, the polymer liquid crystal is arranged on a base material, and the polymer liquid crystal is aligned in a state showing a liquid crystal phase. An anisotropic film manufacturing method.

<6> The copolymer comprises at least one monomer unit derived from a monomer having h + k of 1 in formula (1) and at least one monomer unit derived from a monomer having h + k of 2 in formula (1). A method for producing an optically anisotropic film as described in <5> above.
<7> The method for producing an optically anisotropic film according to <5> or <6>, wherein the alignment is performed using a substrate that has been subjected to an alignment treatment as a base material.
<8> An optically anisotropic film produced by the production method according to any one of <5> to <7>.
<9> An optical element having the optically anisotropic film according to <8> and a support that supports the optically anisotropic film.
<10> The optical element according to <9>, which is used as a retardation plate.

  The optically anisotropic film of the present invention is adjusted by using a polymer liquid crystal composed of a copolymer having a specific monomer unit composition and few impurities, and has high transparency and excellent light resistance to blue laser light. The laminate of the optically anisotropic film and the substrate of the present invention is useful for constituting an optical element such as a retardation plate.

In the present specification, a monomer represented by the formula (1) is referred to as a monomer (1). The same applies to compounds represented by other formulas. A unit (repeating unit) derived from a monomer in the polymer is referred to as a monomer unit. A unit derived from the monomer (1) is referred to as a monomer unit (1), and the other monomer units are also described in the same manner.
The terms used in this specification shall be interpreted according to the following.
“Polymer liquid crystal” means “liquid crystal composed of a polymer capable of exhibiting a liquid crystal phase alone”.
The “clearing point” means “nematic phase-isotropic phase transition temperature” and may be expressed as Tc.

The notation “Ph” represents a 1,4-phenylene group, and a hydrogen atom bonded to a carbon atom in the group is substituted with an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, or a fluorine atom. Can be included. The notation “Cy” represents a trans-1,4-cyclohexylene group, and the hydrogen atom bonded to the carbon atom in the group is an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, or a fluorine atom. Can be substituted.
The notation “Δn” is an abbreviation for “refractive index anisotropy”. In addition, the value of the wavelength in the following description shall include the range of description value +/- 2nm.

<Polymer liquid crystal>
The polymer liquid crystal of the present invention comprises a copolymer containing two or more monomer units derived from the monomer represented by the following formula (1), and is obtained by removing impurities by purification after polymerization. The copolymer is a copolymer obtained by copolymerizing two or more monomers represented by the following formula (1). However, symbols R ¹ , R ² , E ^{1 to} E ⁴ , m, r, n, t, h, and k in the formula (1) are the same as defined above. Monomer (1) is a compound containing a liquid crystalline skeleton composed of a plurality of 6-membered rings. The monomer (1) does not necessarily have to exhibit a liquid crystal phase itself, and a polymer in which the monomer (1) is polymerized may exhibit a liquid crystal phase.
CH ₂ = CR ¹ -COO- (CH ₂ ) _m- (CF ₂ ) _r- (CH ₂ ) _n- (O) _t -E ^1- (E ² ) _h- (E ³ ) _k -E ⁴ -R ² (1).

R ¹ of the monomer (1) is a hydrogen atom or a methyl group. It is preferable that R ¹ is a hydrogen atom because the glass transition point of the copolymer obtained by copolymerizing the monomer (1) is lowered and the orientation control is facilitated.

In the monomer (1), R ² is an alkyl group in which some or all of the hydrogen atoms having 1 to 8 carbon atoms may be substituted with fluorine atoms, and some or all of the hydrogen atoms having 1 to 8 carbon atoms are fluorine. It has an alkoxy group which may be substituted with an atom, or a fluorine atom. This widens the temperature range showing the liquid crystal phase of the copolymer obtained by copolymerizing the monomer (1). When R ² is an alkyl group or an alkoxy group, the number of carbon atoms is preferably 3 to 8, more preferably 3 to 5, and a linear structure can widen the temperature range in which the copolymer exhibits a liquid crystal phase.

E ¹ , E ² , E ³ and E ⁴ are each independently a 1,4-phenylene group or a trans-1,4-cyclohexylene group, and the hydrogen atom bonded to the carbon atom in the group is the number of carbon atoms It may be substituted with an alkyl group of 1 to 10, an alkoxy group of 1 to 10 carbon atoms, or a fluorine atom. When it is substituted with an alkyl group or an alkoxy group, the number of carbon atoms is preferably 1. In particular, in the 1,4-phenylene group, one or two hydrogen atoms bonded to carbon atoms in the group are preferably substituted with a methyl group or a fluorine atom. As a result, the crystallinity of the copolymer tends to be low, and an optically anisotropic film having low haze is likely to be obtained.

m, r, and n are each an integer of 0-6. When r = 0, m + n is an integer of 0 to 10, and an integer of 2 to 6 is more preferable.
When r> 0, r is preferably from 2 to 6, and m and n are preferably from 1 to 3 and the same numerical value.
It is preferable that m + r + n> 0 because the temperature range in which the copolymer exhibits a liquid crystal phase can be widened and alignment control is easy. Although m + r + n = 0 may be used, when this monomer is selected as one kind of comonomer, the monomer unit derived from the monomer is preferably 10 mol% or less in the total monomer units of the copolymer.
t is 0 when m + r + n = 0, and 1 when m + r + n> 0.
h and k are each 0 or 1. It is preferable that at least one of them is 1. When the number of 6-membered rings is increased, the liquid crystal temperature range of the copolymer is widened, and an optically anisotropic film having a low haze is easily obtained. Therefore, the number of 6-membered rings (h + k + 2) is preferably 3 or 4.

  The polymer containing the monomer unit (1) can exhibit high light resistance against blue laser light. In addition, since the copolymer in the present invention is a copolymer containing two or more kinds of monomer units (1), an optically anisotropic film having low crystallinity and high transparency can be formed, and a liquid crystal phase can be formed. The temperature range shown is also easy to widen.

The two or more types of monomer units _{^{(1), -E 1 - (}} E 2) h - (E 3) k -E 4 - is preferably two or more kinds of parts consisting of a number of 6-membered ring It is more preferable that there are two or more different types.
From the viewpoint of low crystallinity and a wide temperature range showing a liquid crystal phase, the copolymer in the present invention is at least monomer units derived from the monomer (1) having three 6-membered rings (h + k is 1). A copolymer containing one kind and at least one kind of monomer unit derived from a monomer (1) having four 6-membered rings (h + k is 2) is preferable. In particular, a copolymer containing at least one monomer unit derived from the following monomer (1A) or (1D) and at least one monomer unit derived from the following monomer (1B) or (1C) is preferable.

CH ₂ = CR ¹ -COO- (CH ₂ ) _{m + n} -O-Ph-Cy-Ph-R ² (1A)
CH ₂ = CR ¹ -COO- (CH ₂ ) _{m + n} -O-Ph-Cy-Ph-Ph-R ² (1B)
CH ₂ = CR ¹ -COO- (CH ₂ ) _m- (CF ₂ ) _r- (CH ₂ ) _n -O-Ph-Cy-Ph-Ph-R ² (1C)
CH ₂ = CR ¹ -COO- (CH ₂ ) _m- (CF ₂ ) _r- (CH ₂ ) _n -O-Ph-Cy-Ph-R ² (1D)

However, in the formula (1A), the formula (1B), the formula (1C), and the formula (1D), the symbols R ¹ and R ² are independent for each formula, and are the same as defined above. In the case of Formula (1A) and Formula (1B), m + n is an integer of 1 to 10. In the case of Formula (1C) and Formula (1D), m and n are the same as those defined above, and r is an integer of 1 to 6. In addition, Ph and Cy are each independently the same as defined above for each formula, and a plurality of Ph in one molecule can also independently represent a substituted or unsubstituted phenylene group.

  In the monomers (1B) and (1C), at least one of the three phenylene groups (Ph) is an alkyl group having 1 to 10 carbon atoms in which a hydrogen atom bonded to a carbon atom in the group is 1 to 10 carbon atoms, It is preferably substituted with an alkoxy group or a fluorine atom. The crystallinity of the copolymer tends to be low, and an optically anisotropic film with low haze is likely to be obtained. Also in the monomer (1A), at least one of the two phenylene groups (Ph) is a hydrogen atom bonded to a carbon atom in the group, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, Alternatively, it is preferably substituted with a fluorine atom.

  The copolymer in the present invention is also preferably a copolymer containing at least one kind of monomer units derived from the monomer (1C) and the monomer (1D). When only one of the monomer units derived from the monomer (1C) and the monomer (1D) is included, a copolymer including at least one type of the monomer unit (1A) and at least one type of the monomer unit (1B) is also preferable. . This is because the copolymer has a low glass transition point (Tg) and a high clearing point (Tc), so that it exhibits liquid crystallinity in a wide range and changes in characteristics due to temperature are small.

More specific examples of the monomer (1A) are shown in Table 1 below. More specific examples of the monomer (1B) are shown in Table 2 below. More specific examples of the monomer (1C) are shown in Table 3 below. More specific examples of the monomer (1D) are shown in Table 4 below. However, the notation Ph (H) in the table represents an unsubstituted 1,4-phenylene group, and Ph (Me) represents 1,1 in which any one hydrogen atom bonded to the benzene ring is substituted with a methyl group. A 4-phenylene group, Ph (F) represents a 1,4-phenylene group in which any one hydrogen atom bonded to the benzene ring is substituted with a fluorine atom, and Ph (Me, Me) represents a benzene ring. 1 represents a 1,4-phenylene group in which any two hydrogen atoms bonded to a methyl group are substituted, and Ph (F, F) represents a fluorine atom in which any two hydrogen atoms bonded to a benzene ring 1,4-phenylene group substituted by is independent for each formula, and a plurality of identical symbols in one molecule are also independent. Cy is the same as defined above, independently for each formula. For example, “1A6” in Table 1 indicates that -Ph-Cy-Ph- is -Ph (Me) -Cy-Ph (H)-,-(CH ₂ ) _{m + n} -is-(CH ₂ ) _6- The monomer (1A) which is is shown. —R ² is selected from the groups described in Table 1. Among “1A6”, a monomer in which —R ² is —C ₃ H ₇ is referred to as a monomer (1A6-C3). Other monomers are also described below.

The monomer (1) is a known compound or a compound obtained according to a known method. For example, WO2006 / 001096 pamphlet and WO2007 / 046294 pamphlet related to the inventors' invention describe a monomer having a structure in which three or four six-membered rings are directly connected, and a method for producing the monomer. A part of said monomer (1) is a compound described in these documents, and is a compound which can be manufactured with the manufacturing method described in these documents. Furthermore, the monomers (1C) and (1D) are prepared by using HO— (CH ₂ ) _{m + n} —OH derivatives in the process for producing the monomers (1A) and (1B), instead of the diol. (CH ₂ ) _m- (CF ₂ ) _r- (CH ₂ ) _n -OH can be used to produce the same method.

  The copolymer in the present invention preferably has a glass transition point (Tg). In a crystalline polymer having no glass transition point, crystals are likely to precipitate, and the optically anisotropic film formed from a polymer liquid crystal may have low transparency. Therefore, the copolymer in the present invention preferably has no melting point (Tm). The clearing point (Tc) of the copolymer in the present invention is preferably 100 ° C. or higher, and particularly preferably 150 ° C. or higher. The copolymer preferably exhibits a smectic liquid crystal phase, and preferably has a high upper limit temperature in the smectic liquid crystal temperature range. This is because the characteristic change due to temperature of the optically anisotropic film formed from the polymer liquid crystal is small. The glass transition point (Tg), melting point (Tm), and clearing point (Tc) of the copolymer are equal to those measured from the polymer liquid crystal of the present invention because of the high purity of the copolymer in the polymer liquid crystal. .

  The ratio of the monomer unit (1A) and / or monomer unit (1D) to the monomer unit (1B) and / or monomer unit (1C) in the copolymer is preferably 30:70 to 70:30, and 60:40 to 40:60 is more preferable. When there are many monomer units (1A) in a copolymer, there exists a tendency for the crystallinity of a copolymer to fall, On the other hand, Tc becomes low, the range which develops a nematic phase is wide, and there exists a tendency for the characteristic change by temperature to become large. When there are many monomer units (1B) and / or monomer units (1C) in the copolymer, Tc becomes high, the smectic phase is expressed in a wide range, and the characteristic change due to temperature tends to be small. There is a tendency to go up. In order to develop a smectic phase, it is preferable that the monomer unit (1B) and / or the monomer unit (1C) with respect to all the monomer units is 50 mol% or more.

  The copolymer in the present invention may have monomer units other than the monomer unit (1) as long as the object can be achieved. However, it is not preferable to have a monomer unit that reduces the durability against blue laser light. For example, a monomer unit having a cyano group or a monomer unit having -Ph-C (= O)-reduces the durability against blue laser light. As long as it is a monomer unit other than the monomer unit (1) and does not decrease the durability against blue laser light, it may be contained in the copolymer up to less than 20 mol% with respect to the total monomer units. The copolymer in the present invention preferably contains 95 mol% or more of monomer units (1) with respect to all monomer units, and more preferably substantially all monomer units are composed of monomer units (1).

  The number average molecular weight of the copolymer in the present invention is preferably 3,000 to 50,000, more preferably 5,000 to 30,000. Most preferably, it is 5,000-20,000. If the molecular weight is too small, the crystallinity tends to be easily obtained, and the optically anisotropic film formed using the polymer liquid crystal may have low transparency. If the molecular weight is too large, it takes time to control the alignment or the orientation degree of the liquid crystal tends to be low, and as a result, the optically anisotropic film may have low transparency. The number average molecular weight is a value measured by gel permeation chromatography using polystyrene as a standard substance.

The copolymer in the present invention is synthesized by a general polymerization method such as solution polymerization, suspension polymerization or emulsion polymerization. In the case of solution polymerization, the solvent used for the polymerization may be any solvent in which the monomer and copolymer are dissolved, and examples thereof include dimethylformamide, toluene, dichloromethane, chloroform, tetrahydrofuran, and the like, and toluene having a low chain mobility is more preferable. When performing solution thermal polymerization, it is preferable to use a thermal polymerization initiator, and an azo-based initiator is more preferable. One or more thermal polymerization initiators can be used. The amount of the thermal polymerization initiator is preferably from 0.1 to 5 mass%, particularly preferably from 0.3 to 2 mass%, based on the total amount of monomers. The polymerization temperature is preferably near the half-life temperature of the initiator.
In order to adjust the molecular weight of the copolymer, it is preferable to use a chain transfer agent in the polymerization reaction. The chain transfer agent is preferably a thiol compound such as 1-dodecanethiol because the transparency and light resistance of the optically anisotropic film formed using the polymer liquid crystal are improved. The amount of the chain transfer agent is preferably 0 to 5% by mass, particularly preferably 1 to 3% by mass, based on the total amount of monomers.

  The recovered product obtained by copolymerizing the monomers contains impurities. Examples of impurities include unreacted polymerization initiators, decomposition products of polymerization initiators, and unreacted monomers. As a purification method to remove impurities, a method in which the synthesized polymer does not dissolve but is washed using a solvent in which the impurity is dissolved; a polymer solution is prepared once using a solvent in which the synthesized polymer is dissolved, and the polymer is dissolved. Instead, a general polymer purification method such as a method of reprecipitation using a solvent in which impurities are dissolved is used. In particular, it is preferable to combine washing and reprecipitation and to perform this combination once or more. Examples of the solvent in which the polymer dissolves include ether solvents such as tetrahydrofuran, chlorinated hydrocarbon solvents such as dichloromethane and chloroform, and aromatic hydrocarbon solvents such as toluene. Examples of the solvent in which the polymer does not dissolve and the impurity dissolves include alcohol solvents such as methanol and aliphatic hydrocarbon solvents such as hexane.

The polymer liquid crystal of the present invention is composed of the above-described polymer having a high purity obtained by removing impurities by purification after polymerization. The amount of the compound (impurity) having a number average molecular weight of 1000 or less contained in the polymer liquid crystal of the present invention is preferably less than 1% by mass and less than 0.5% by mass with respect to the total amount of the polymer and the compound having a molecular weight of 1000 or less. It is more preferable that it is less than 0.2% by mass. That is, the ratio of the polymer having a number average molecular weight of more than 1000 (polymer purity) in the polymer liquid crystal is preferably 99% by mass or more, more preferably 99.5% by mass or more, and 99.8% by mass. The above is particularly preferable. When the purity of the polymer is expressed by mass%, the value of the total peak area (A _t ) of UV absorption and the peak area of UV absorption (A ₁₀₀₀ ) having a number average molecular weight of 1000 or less in the measurement for obtaining the number average molecular weight. from means a value calculated by the calculation formula _{(a t -A 1000) × 100} / a t.

<Optically anisotropic film and optical element>
Hereinafter, a method for forming an optically anisotropic film using the polymer liquid crystal of the present invention will be described.
When forming the optically anisotropic film, other components may be mixed into the polymer liquid crystal as long as the light resistance against blue laser light is not adversely affected. Examples of other components include chiral agents, antioxidants, light stabilizers, and dichroic dyes.
When using an ultraviolet absorber, an antioxidant, a light stabilizer or the like as the other component, the amount of these components is preferably 5% by mass or less, particularly preferably 2% by mass or less, based on the polymer liquid crystal. These are not included in impurities.

  The optically anisotropic film of the present invention is obtained by aligning a polymer liquid crystal uniaxially or biaxially. Specifically, an optically anisotropic film supported on a substrate is obtained by applying a polymer liquid crystal to an alignment-treated substrate, heat-treating and aligning it, and using this as an optical element as it is Can do. As a method for forming an optically anisotropic film from the polymer liquid crystal of the present invention, general film forming methods such as the following (1) to (3) are used.

  (1) Method of injecting polymer liquid crystal into cell: Polymer liquid crystal is heated to a temperature equal to or higher than its clearing point (Tc) and injected from the injection port of the cell. When heated above Tc, the viscosity of the polymer liquid crystal decreases and the injection time is shortened. Further, since injection unevenness occurs when the injection is performed at Tc or lower, the injection at Tc or higher is preferable. It is preferable to perform the injection under a nitrogen flow so that the polymer liquid crystal is not oxidized. When the polymer liquid crystal is oxidized, coloring may occur or light resistance may deteriorate. The film thickness of the optically anisotropic film can be controlled to the cell thickness. After the injection, annealing is performed for about 1 to 10 minutes at a temperature at which the alignment of the polymer liquid crystal can be changed, for example, at a temperature of about (Tc-10) ° C., thereby increasing the degree of alignment of the liquid crystal. Thereafter, it is gradually cooled to room temperature to obtain a liquid crystal cell in which polymer liquid crystals are aligned.

  (2) Melt casting method: A polymer liquid crystal is placed on a substrate subjected to an alignment treatment heated to a temperature equal to or higher than the clearing point (Tc) of the polymer liquid crystal. Remove bubbles derived from residual solvent in polymer liquid crystal. Thereafter, in order to make the substrate gap constant, a silica spacer is placed on the liquid crystal. Further thereon, a substrate subjected to another orientation treatment is placed and pressed until it hits the silica spacer. The film thickness of the optically anisotropic film can be controlled to the diameter of the silica spacer. When annealing is performed for about 1 to 10 minutes at a temperature at which the orientation of the polymer liquid crystal can be changed, for example, at a temperature of about (Tc-10) ° C., the degree of alignment of the liquid crystal increases. Thereafter, it is gradually cooled to room temperature to obtain a liquid crystal cell in which polymer liquid crystals are aligned.

  (3) Solution casting method: 5-40% by mass of a polymer liquid crystal is dissolved in an organic solvent in which the polymer liquid crystal is dissolved, and applied by spin coating onto a substrate subjected to an alignment treatment. After film formation, the organic solvent is slowly evaporated at a relatively low temperature. Thereafter, when the annealing is performed for about 1 to 10 minutes at a temperature at which the orientation of the polymer liquid crystal can be changed, for example, a temperature of about (Tc-10) ° C., the degree of alignment of the liquid crystal becomes high. Then, the board | substrate which has the polymer liquid crystal layer orientated by cooling slowly to room temperature can be obtained. The film thickness can be controlled by the solution concentration of the polymer liquid crystal and the rotation speed of the spin coat. Unevenness of film thickness is more likely to occur than cell injection and sandwich film formation.

  As a method for applying the polymer liquid crystal solution onto the substrate, die coating, extrusion coating, roll coating, wire bar coating, gravure coating, spray coating, dipping, printing, or the like can be employed instead of the above spin coating. Tetrahydrofuran, toluene, methylene chloride, chloroform and the like can be used as the organic solvent. The organic solvent may be used alone or in combination of a plurality of types, and may be appropriately selected in consideration of the vapor pressure and the solubility of the polymer liquid crystal. As a method for volatilizing the organic solvent, natural drying, heat drying, vacuum drying, and vacuum heating drying can be used.

As the substrate, for example, a substrate rubbed with fibers such as cotton, wool, nylon, polyester, etc .; a substrate formed with an organic thin film on the surface and rubbed with cloth, etc .; an alignment film on which SiO ₂ is obliquely deposited A substrate or the like can be used, and the polymer liquid crystal on the substrate is aligned by preparing a substrate subjected to such an alignment process and arranging the polymer liquid crystal.

  As a shape of the substrate, in addition to a flat plate, a curved surface may be included as a constituent part. The material which comprises a board | substrate can be used regardless of an organic material and an inorganic material. Examples of the organic material used as the substrate material include polyethylene terephthalate, polycarbonate, polyimide, polyamide, polymethyl methacrylate, polystyrene, polyvinyl chloride, polytetrafluoroethylene, polychlorotrifluoroethylene, ethylene / tetrafluoroethylene copolymer, Examples include polyethylene, polypropylene, polyarylate, polysulfone, triacetyl cellulose, cellulose, polyether ether ketone, and examples of the inorganic material include silicon, glass, calcite, and the like.

  If proper orientation cannot be obtained by rubbing the substrate with fibers such as cotton, wool, nylon, polyester, etc., an organic thin film such as a polyimide thin film or a polyvinyl alcohol thin film is formed on the substrate surface according to a known method. Then, it may be rubbed with a cloth or the like.

  In order to further improve the coating property of the polymer liquid crystal, it is also effective to provide an intermediate layer such as a polyimide thin film on the substrate. An intermediate layer such as a polyimide thin film is also effective as means for improving adhesion when the adhesion between the polymer liquid crystal and the substrate is not good.

  The thickness of the optically anisotropic film is preferably from 0.1 to 20 μm, more preferably from 0.5 to 10 μm, still more preferably from 1 to 7 μm. If it is thinner than 0.1 μm, the expression of optical properties is reduced, and if it exceeds 20 μm, it is not preferred because it is difficult to align.

  In the present invention, an optically anisotropic film obtained using a polymer liquid crystal may be used while being held on a support using the substrate as a support, or may be used after being peeled off from the substrate. Further, the obtained optically anisotropic film may be laminated or used by being bonded to another substrate. Since the optically anisotropic film of the present invention is optically transparent and has anisotropy, it is useful for applications utilizing the function of modulating polarized light. Specifically, it is useful for use in modulating the phase state or wavefront state of polarized light, and can be suitably applied to an optical element having an optical anisotropic film. For example, the optical element having the optically anisotropic film of the present invention can be used as a retardation plate or the like mounted on a liquid crystal display or an optical pickup device.

  Various alignment methods such as TN, STN, ECB, VA, IPS, OCB have been proposed for liquid crystal cells used in liquid crystal displays. In order to obtain sufficient image quality (contrast, color purity, viewing angle characteristics, response speed) as a display, all methods require a comprehensive optical design with other optical members in addition to the liquid crystal cell. The polarization state emitted from the liquid crystal cell is not necessarily optically preferable depending on the viewing angle. For the purpose of compensating for this, a retardation plate having anisotropy of refractive index is used. The phase difference plate is classified according to the refractive index structure in three dimensions, that is, the shape of the refractive index ellipsoid, such as positive A plate, negative A plate, positive C plate, negative C plate, etc. Can be mentioned. In addition, a twist phase difference film, a viewing angle widening film, a temperature compensation type film, and the like can be given.

  An example of using the optical pickup device mounted on an optical pickup device is a wave plate with a controlled retardation value. Examples include a quarter wavelength plate controlled to ¼ of the wavelength and a ½ wavelength plate made half of the wavelength. The wave plate is an element that can convert incident polarized light, the half wave plate can be used as an element that switches between P-polarized light and S-polarized light, and the quarter wave plate can be used as an element that switches between linearly polarized light and circularly polarized light. By using an element that converts polarized light, incident light utilization efficiency (transmittance), information reading accuracy, and the like are improved.

The polymer liquid crystal of the present invention takes a uniaxial or biaxial alignment state. Examples of the uniaxial alignment state include those in which polymer liquid crystals are horizontally aligned, vertically aligned, and twisted aligned. In addition, the biaxial alignment state includes a hybrid alignment of polymer liquid crystals.
In order to make a film having an alignment state of horizontal alignment and vertical alignment, a cell using two substrates each coated with an alignment film for horizontal alignment, and a cell using two substrates coated with an alignment film for vertical alignment, respectively. Is used. In order to produce a hybrid oriented film, a cell using a substrate coated with an alignment film for horizontal alignment and a substrate coated with an alignment film for vertical alignment is used. A twist-aligned film can be produced by using a cell using two substrates in which a polymer liquid crystal obtained by copolymerizing a chiral liquid with a polymer liquid crystal is coated with an alignment film for horizontal alignment.

  Films in these orientation states function as retardation films, horizontal orientation films as positive A plates and wave plates (1/4 and 1/2), vertical orientation films as positive C plates, and twist orientation orientation. The film can be used as a twisted phase difference plate, and the film of hybrid orientation can be used as a viewing angle widening film. Further, in addition to the above applications, it also functions as a temperature compensation film depending on temperature characteristics.

  Hereinafter, the present invention will be described based on Examples (Examples 1 to 5, 9, 13 to 17, 21) and Comparative Examples (Examples 6 to 8, 10 to 12, 18 to 20, 22 to 24). The invention is not limited to these.

(Molecular weight, polymer purity)
The number average molecular weight in terms of polystyrene was determined using GPC (manufactured by Tosoh Corporation, product name: HLC-8220). The polymer purity (% by mass) was determined from the following formula from the total peak area (A _t ) of UV absorption and the peak area (A ₁₀₀₀ ) of UV absorption having a number average molecular weight of 1000 or less.
(A _t -A ₁₀₀₀ ) × 100 / A _t .

(Measurement of melting point, glass transition point, phase transition temperature)
The peak temperature was identified using DSC (Bruker AX, product name: DSC3100S). The temperature rising rate was 10 ° C./min. Moreover, the liquid crystal phase and the crystal were identified by observation using a polarizing microscope (manufactured by Olympus, product name: BX-51).

(Orientation state)
Using an optical material inspection apparatus (manufactured by Otsuka Electronics Co., Ltd., product name: RETS-100), the measurement was performed by the rotational analyzer method and analyzed.

(Haze)
It measured using the haze meter (Suga Test Instruments Co., Ltd. product name: HGM-3K).

(Light resistance test)
A blue laser (wavelength of 405 nm) was irradiated, and a blue laser light exposure acceleration test was performed. The irradiation conditions were a temperature of 80 ° C. and an integrated exposure energy of 72 KJ / mm ² . The fluctuation range of the transmittance after the test with respect to the transmittance before the acceleration test of light having a wavelength of 405 nm was examined. A case where the fluctuation range was less than 1% was regarded as a non-defective product, and a case where it was 1% or more was regarded as a defective product. In addition, the spectrophotometer (Hitachi company make, U-4100) was used for the measurement of the transmittance | permeability.

  The monomers used for the production of the polymer liquid crystal are shown below. The following monomer (1B3-C3) and monomer (X-1) are known compounds, and a method for synthesizing the monomer (1B3-C3) is described in [Synthesis Example 6] of the above-mentioned WO2007 / 046294 pamphlet. A synthesis method of the following monomer (1A6-C3) and monomer (1C3-C3) is shown below.

[Synthesis Example 1] Synthesis of monomer (1A6-C3) used in Examples Monomer (1A6-C3) was synthesized by the following synthesis route. Details are described below.

Synthesis of compound (13):
To a 1 L four-necked flask equipped with a reflux apparatus and a dropping apparatus, magnesium (6.45 g) was added and dissolved in 4-propylbromobenzene (compound (11), 50 g) and dehydrated tetrahydrofuran (200 mL). It was added dropwise under a nitrogen stream over 60 minutes. After completion of dropping, 100 mL of dehydrated tetrahydrofuran was further dropped and stirred for 2 hours to prepare a Grignard reagent. Next, this four-necked flask was cooled to 0 ° C., and 1,1′-bicyclohexane-1,4-dione monoethylene ketal (compound (12), 35.1 g) was dissolved in dehydrated tetrahydrofuran (200 mL). Was added dropwise over 60 minutes under a nitrogen stream. After completion of the dropwise addition, the mixture was stirred at room temperature for 2 hours, and an aqueous ammonium chloride solution was added to stop the reaction.

  Next, water and diethyl ether were added for liquid separation, and the organic layer was recovered. The collected organic layer was washed with a saturated aqueous sodium chloride solution (40 mL), then washed with water, and the organic layer was collected again. The organic layer was dried over anhydrous magnesium sulfate, the anhydrous magnesium sulfate was removed by filtration under reduced pressure, and the filtrate was concentrated. The obtained solid was purified by column chromatography using hexane / dichloromethane (5: 5, volume ratio) as a developing solution to obtain 42.4 g of compound (13). The yield was 68.3%.

Synthesis of compound (14):
Compound (13) (40 g) and 50 mL of trifluoroacetic acid were added to a 500 mL four-necked flask equipped with a reflux apparatus and a stirrer, and the mixture was stirred at room temperature for 1 hour. After completion of the reaction, a saturated aqueous sodium hydrogen carbonate solution was added to stop the reaction. Next, water and diethyl ether were added for liquid separation, and the organic layer was recovered. The collected organic layer was washed with a saturated aqueous sodium chloride solution (40 mL), then washed with water, and the organic layer was collected again. The organic layer was dried over anhydrous magnesium sulfate, the anhydrous magnesium sulfate was removed by filtration under reduced pressure, and the filtrate was concentrated. The reaction mixture was poured into it and extracted with diethyl ether. The organic layer was washed with saturated brine, dried over magnesium sulfate, and the solvent was evaporated. The obtained solid was purified by column chromatography using ethyl acetate / hexane (7: 3, volume ratio) as a developing solution to obtain 26.3 g of compound (14). The yield was 84.1%.

Synthesis of compound (15):
Compound (14) (25 g), 10% palladium activated carbon (3 g) and dehydrated tetrahydrofuran (300 mL) were added to a 500 mL pressure vessel, and hydrogen was charged to 0.4 Mpa. While maintaining the internal pressure at 0.4 Mpa, the mixture was stirred at room temperature for 8 hours until the pressure did not drop. After completion of the reaction, 10% palladium activated carbon was filtered, and the filtrate was concentrated. The obtained solid was purified by column chromatography using ethyl acetate / hexane (7: 3, volume ratio) as a developing solution to obtain 22.7 g of compound (15). The yield was 89.9%.

Synthesis of compound (17):
To a 500 mL four-necked flask equipped with a reflux apparatus, a stirrer, and a dropping apparatus, magnesium (1.53 g) was added and compound (15) (19.3 g) was dissolved in dehydrated tetrahydrofuran (50 mL). The dropwise addition took 30 minutes under a nitrogen stream. After completion of dropping, the mixture was stirred and refluxed at 70 ° C. for 3 hours to prepare a Grignard reagent. Next, this four-necked flask was cooled to 0 ° C., and compound (16) (17.1 g) dissolved in dehydrated tetrahydrofuran (100 mL) was added dropwise over 30 minutes under a nitrogen stream. . After completion of the dropwise addition, the mixture was stirred and refluxed at 70 ° C. for 3 hours, and a 1 mol / L aqueous ammonium chloride solution (100 mL) was added to stop the reaction.

  Next, water and diethyl ether were added for liquid separation, and the organic layer was recovered. The collected organic layer was washed with a saturated aqueous sodium chloride solution (40 mL), then washed with water, and the organic layer was collected again. The organic layer was dried over anhydrous magnesium sulfate, the anhydrous magnesium sulfate was removed by filtration under reduced pressure, and the filtrate was concentrated. The obtained filtrate was purified by column chromatography using ethyl acetate / hexane (7: 3, volume ratio) as a developing solution to obtain 20.7 g of compound (17). The yield was 68%.

Synthesis of compound (18):
Compound (24) (20.3 g), paratoluenesulfonic acid monohydrate (0.65 g), and toluene (400 mL) were added to a 500 mL eggplant-shaped flask equipped with a reflux apparatus and a stirrer, and molecular sieve was added thereto. An isobaric dropping funnel containing 4A (50 g) was attached, and the mixture was stirred and refluxed at 110 ° C. for 4 hours. After completion of the reaction, water and diethyl ether were added for liquid separation, and the organic layer was recovered. The collected organic layer was washed with a saturated aqueous sodium chloride solution (40 mL), then washed with water, and the organic layer was collected again. The organic layer was dried over anhydrous magnesium sulfate, then anhydrous magnesium sulfate was removed by filtration under reduced pressure, and the filtrate was concentrated to obtain 14.9 g of compound (18). The yield was 71%.

Synthesis of compound (19):
The 5 L pressure-resistant reactor equipped with a stirrer is sufficiently degassed, and compound (18) (12.4 g), tetrahydrofuran (200 mL), 10% palladium activated carbon (2.5 g) are added under reduced pressure, and then Hydrogen was added to 0.4 MPa, and the mixture was stirred at a low temperature for about 2 hours. After purging excess hydrogen, the solid was removed by filtration and the filtrate was washed with 100 mL of diethyl ether. Then, it concentrated by the evaporator and obtained the cis-trans mixture (11.6g) of the compound (19). The yield was 95%.
Hexane (100 mL) was added thereto and recrystallization was performed to obtain a trans isomer (2.00 g) of compound (19). The filtrate was concentrated, transferred to a 500 mL eggplant-shaped flask, t-butoxypotassium (28.0 g) and N, N-dimethylformamide (300 mL) were added, and the mixture was stirred and refluxed at 100 ° C. for 6 hours. The cis form of 19) was converted to a trans form. After completion of the reaction, water (500 mL) was added to stop the reaction, and diethyl ether was added for liquid separation, and the organic layer was recovered. The collected organic layer was washed with a saturated aqueous sodium chloride solution (40 mL), then washed with water, and the organic layer was collected again. The organic layer was dried over anhydrous magnesium sulfate, the anhydrous magnesium sulfate was removed by filtration under reduced pressure, the filtrate was concentrated, hexane (100 mL) was added, recrystallization was performed, and the trans isomer of compound (19) (2.07 g ) The total yield of the compound (26) as a trans isomer was 4.07 g, and the yield was 32%.

Synthesis of compound (20):
Compound (19) (3.75 g) and dichloromethane (200 mL) were added to a 500 mL four-necked flask equipped with a reflux apparatus, a stirrer, and a dropping apparatus. Under a nitrogen stream, boron tribromide (12.74 g) was added dropwise over 30 minutes. The dropping operation was performed while cooling with ice so that the internal temperature did not exceed 10 ° C. After stirring at room temperature for 3 hours, the reaction was stopped by adding water, and diethyl ether was added for liquid separation, and the organic layer was recovered. The collected organic layer was washed with a saturated aqueous sodium chloride solution (40 mL), then washed with water, and the organic layer was collected again. The organic layer was dried over anhydrous magnesium sulfate, the anhydrous magnesium sulfate was removed by filtration under reduced pressure, the filtrate was concentrated, recrystallized using a mixed solvent of dichloromethane and hexane (100 mL), and compound (20) ( 3.53 g) was obtained. The yield was 95%.

Synthesis of monomer (1A6-C3):
Compound _{(20) (5.25g), CH} 2 = CH-COO- (CH 2) 6 -Br (3.37g), potassium carbonate (4.22 g), potassium iodide (0.409 g), and anhydrous acetone (200 mL) was heated to reflux for 24 hours. Diethyl ether (100 mL) and water (200 mL) were added for liquid separation, and the organic layer was recovered. The organic layer was washed with 1M hydrochloric acid (100 mL) and then with a saturated sodium chloride solution (200 mL), and then the organic layer was collected again. The organic layer was dried over anhydrous magnesium sulfate, and then anhydrous magnesium sulfate was removed by filtration under reduced pressure. The solvent was distilled off under reduced pressure, and the resulting residue was purified by column chromatography (development ratio: dichloromethane / hexane = 5/5, volume ratio) to obtain a fraction containing the desired product. The fraction was concentrated to obtain a powdered product. Hexane (100 mL) was added to the powder crystals and recrystallized to obtain monomer (1A6-C3) (5.81 g). The yield was 74%.

Spectral data of the monomer (1A6-C3);
¹ H-NMR (300.4 MHz, solvent: CDCl ₃ , standard: TMS) δ (ppm): 0.95 (t, 3H), 1.46-2.06 (m, 18H), 2.33 (s , 3H), 2.54-2.59 (m, 4H), 3.91-3.95 (t, 2H), 4.14-4.19 (t, 2H), 5.79-5.83. (Dd, 1H), 6.08-6.17 (dd, 1H), 6.37-6.43 (dd, 1H), 6.70-6.73 (d, 2H), 7.11-7 .26 (m, 9H).

[Synthesis Example 2] Synthesis of monomer (1C3-C3) used in Examples Monomer (1C3-C3) was synthesized by the synthesis route shown below. Details are described below.

Synthesis of compound (32):
Compound (31) (50.0 g) and 3,4-dihydropyran (7.0 mL) were added to a 5 L four-necked flask equipped with a reflux apparatus and a stirrer, and p-toluenesulfone in dichloromethane (3500 mL). Reaction at room temperature in the presence of acid (0.54 g) gave 20.68 g of compound (32).

Synthesis of compound (29):
Compound (32) (24.87 g), ether (500 mL), and triethylamine (14 mL) were added to a 1 L four-necked flask equipped with a reflux apparatus and a stirrer. After cooling to 0 ° C., 1,1,2,2,3,3,4,4,4-nonafluorobutanesulfonyl fluoride (12.31 mL) was added, and the temperature was gradually raised to room temperature and stirred for 40 hours. . Water (300 mL) and t-butyl methyl ether (400 mL) were added, and the organic layer was washed with saturated brine, dried and then the solvent was removed to remove 1,1,2,2,3,3,4,4,4. Crude of 2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoro-8- (tetrahydro-2H-pyran-2-yloxy) octyl 4-nonafluorobutanesulfonate A purified product (52.1 g) was obtained.
This crude product (36.99 g) and compound (28) (13.86 g) were dissolved in N, N-dimethylformamide (300 mL), cesium carbonate (42.78 g) was added, and 0.5 ° C. was added at 80 ° C. Stir for hours. Water (400 mL) was added and extracted with t-butyl methyl ether (250 mL × 3 times). The obtained organic layer was washed with saturated brine (250 mL), and then the solvent was removed to obtain a crude product of compound (29). This crude product was purified by column chromatography using hexane / ethyl acetate (15: 1, volume ratio) as a developing solution to obtain 25.38 g of compound (29). The yield was 61.5%.

Synthesis of compound (30):
A compound (29) (25.37 g), methanol (400 mL) and tetrahydrofuran (50 mL), p-toluenesulfonic acid monohydrate (0.71 g) were added to a 1 L four-necked flask equipped with a reflux apparatus and a stirrer. In addition, the mixture was stirred at room temperature for 3 hours. Triethylamine (4.09 mL) was added, and the solvent was distilled off under reduced pressure to obtain a crude product. This crude product was purified by column chromatography using hexane / ethyl acetate (6: 1, volume ratio) as a developing solution to obtain 19.50 g of compound (30). The yield was 93%.

Synthesis of monomer (1C3-C3):
Compound (30) (19.50 g), dichloromethane (500 mL) and triethylamine (6 mL) were added to a 1 L four-necked flask equipped with a reflux apparatus and a stirrer and cooled to 0 ° C. Acrylic acid chloride (3.40 mL) was added, and the mixture was gradually raised to room temperature and stirred for 14 hours. The solvent was distilled off under reduced pressure, and the resulting crude product was purified by column chromatography using hexane / ethyl acetate (10: 1, volume ratio) as a developing solution to obtain 16.96 g of monomer (1C3-C3). Got. The yield was 84%.

Spectral data of the monomer (1C3-C3);
¹ H-NMR (300.4 MHz, solvent: CDCl ₃ , standard: TMS) δ (ppm): 0.99 (t, 3H), 1.53 to 2.05 (m, 10H), 2.29 (s 3H), 2.63 (m, 4H), 4.45 (t, 2H), 4.67 (t, 2H), 5.98 (dd, 1H), 6.18 (dd, 1H), 6 .53 (dd, 1H), 6.91 (m, 2H), 7.11-7.23 (m, 9H).
¹⁹ F-NMR (282.7 MHz, solvent: CDCl ₃ , standard: TMS) δ (ppm): −120.0 (m, 4F), −122.5 (m, 4F), −123.7 (m, 2F), -123.9 (m, 2F).

[Synthesis Example 3] Synthesis of monomer (1D5-C3) used in Examples

Synthesis of compound (34):
Compound (33) (50.0 g) and 3,4-dihydropyran (9.6 mL) were added to a 5 L four-necked flask equipped with a reflux apparatus and a stirrer, and p-toluenesulfone in dichloromethane (500 mL). Reaction at room temperature in the presence of acid (0.74 g) gave 24.90 g of compound (34).

Synthesis of compound (35):
Compound (34) (24.90 g), ether (500 mL), and triethylamine (14.3 mL) were added to a 1 L four-necked flask equipped with a reflux apparatus and a stirrer. After cooling to 0 ° C., 1,1,2,2,3,3,4,4,4-nonafluorobutanesulfonyl fluoride (17.3 mL) was added, and the temperature was gradually raised to room temperature and stirred for 20 hours. . Water (500 mL) and t-butyl methyl ether (400 mL) were added, and the organic layer was washed with saturated brine, dried and then the solvent was removed to remove 1,1,2,2,3,3,4,4,4. A crude product (44.5 g) of 4-nonafluorobutanesulfonic acid 2,2,3,3,4,4,5,5-octafluoro-6- (tetrahydro-2H-pyran-2-yloxy) hexyl was obtained. Obtained.

  This crude product (22.50 g) and compound (20) (10.43 g) were dissolved in N, N-dimethylformamide (400 mL), cesium carbonate (36.26 g) was added, and the mixture was stirred at 80 ° C. for 1 hour. did. Water (300 mL) was added and extracted with t-butyl methyl ether (300 mL). The obtained organic layer was washed with saturated brine (300 mL), and then the solvent was removed to obtain a crude product of compound (35). This crude product was purified by column chromatography using hexane / ethyl acetate as a developing solution to obtain 18.48 g of compound (35). The yield was 86%.

Synthesis of compound (36):
A compound (35) (18.48 g), methanol (300 mL) and tetrahydrofuran (300 mL), and p-toluenesulfonic acid monohydrate (0.66 g) were added to a 1 L four-necked flask equipped with a reflux apparatus and a stirrer. In addition, the mixture was stirred at room temperature for 30 hours. Triethylamine (0.50 mL) was added, and the solvent was distilled off under reduced pressure to obtain a crude product. This crude product was purified by column chromatography using hexane / ethyl acetate as a developing solution to obtain 16.04 g of compound (36). The yield was 100%.

Synthesis of monomer (1D5-C3):
Compound (36) (16.04 g), dichloromethane (300 mL) and triethylamine (6.18 mL) were added to a 1 L four-necked flask equipped with a reflux apparatus and a stirrer, and cooled to 0 ° C. Acrylic acid chloride (3.61 mL) was added, and the mixture was gradually raised to room temperature and stirred for 11 hours. The solvent was distilled off under reduced pressure, and the resulting crude product was purified by column chromatography using hexane / ethyl acetate as a developing solution to obtain 11.80 g of monomer (1D5-C3). The yield was 67%.

Spectral data of the monomer (1D5-C3);
¹ H-NMR (300.4 MHz, solvent: CDCl ₃ , standard: TMS) δ (ppm): 0.95 (t, 3H), 1.53 to 2.05 (m, 10H), 2.35 (s , 3H), 2.54-2.80 (m, 4H), 4.43 (t, 2H), 4.67 (t, 2H), 5.97 (dd, 1H), 6.18 (dd, 1H), 6.52 (dd, 1H), 6.77 (m, 2H), 7.11-7.21 (m, 5H).
¹⁹ F-NMR (282.7 MHz, solvent: CDCl ₃ , standard: TMS) δ (ppm): −120.2 (m, 4F), −124.0 (m, 2F), −124.2 (m, 2F).

[Example 1]
Example of polymer liquid crystal synthesis:
Monomer (1A6-C3) (0.563 g), monomer (1B3-C3) (0.437 g), polymerization initiator (trade name “V40” manufactured by Wako Pure Chemical Industries, 0.01 g) ), Chain transfer agent 1-dodecanethiol (0.025 g), and toluene (1.25 g) were added, and the atmosphere was replaced with nitrogen, followed by sealing. The screw mouth test tube was stirred and shaken in a constant temperature bath at 80 ° C. for 18 hours for polymerization.
After the polymerization content was stirred in methanol for 10 minutes, the operation of taking out the polymer was performed three times. Thereafter, the polymer was dissolved in tetrahydrofuran and dropped into stirring methanol for reprecipitation. Furthermore, after stirring a polymer for 10 minutes in methanol, operation which takes out a polymer was performed 3 times. The liquid crystalline polymer was reprecipitated again for purification, and dried in a vacuum dryer at 40 ° C. for 2 hours to obtain a white polymer liquid crystal 1. The yield was 0.90 g and the yield was 90%.

[Example 2] to [Example 11]
Example of polymer liquid crystal synthesis:
In the synthesis of the polymer liquid crystal 1, polymerization and purification were performed in the same manner except that the raw material composition was changed as shown in Table 5, and polymer liquid crystals 2 to 11 were obtained. In Table 5, “phr” indicates the ratio of the chain transfer agent to 100 parts by mass of the monomer and the ratio of the initiator, and “M / S” indicates the mass of the monomer / the mass of the solvent.

  Table 6 shows the number average molecular weight (Mn), melting point (Tm), glass transition point (Tg), transition temperature from smectic phase to nematic phase, polymer purity, and clearing point (Tc) of the obtained polymer liquid crystals 1 to 11. Indicated.

[Example 12]
Monomer (1A6-C3), monomer (1B3-C3), and monomer (1C3-C3) were mixed at a ratio of 45/45/10 (mol%) (same as the monomer blend ratio in Example 3). 0.5 parts by weight of a polymerization initiator (trade name “Irgacure 754” manufactured by Ciba Specialty Chemicals Co., Ltd.) was added to 100 parts by mass of all monomers to obtain a polymerizable liquid crystal composition.
A polymerizable liquid crystal composition was injected at 110 ° C. into a cell with an alignment film (manufactured by EHC, trade name “KSRP-05”, cell gap 5 μm, 25 mm × 22 mm × 0.7 mm). At 160 ° C., ultraviolet rays having an intensity of 135 mW / cm ² were irradiated for 3 minutes for photopolymerization to obtain a sample.
The melting point (Tm), the transition temperature from the smectic phase to the nematic phase, and the clearing point (Tc) were measured as they were. A polymer (hereinafter referred to as polymer liquid crystal 12) in the cell with an alignment film was taken out from this sample, and the number average molecular weight and polymer purity were measured. The evaluation results are shown in Table 6.

[Example 13]
Example of production and evaluation of optically anisotropic film:
(Sample 1) The polymer liquid crystal obtained in Example 1 was placed on an alignment-treated glass substrate (20 mm × 25 mm × 0.7 mm). After heating above the clearing point (Tc) of the polymer liquid crystal under nitrogen gas flow, another alignment-treated glass substrate was placed on the polymer liquid crystal. With the silica beads having a diameter of 3 μm sandwiched between two glass substrates, the polymer liquid crystal was aligned by annealing at a temperature 10 ° C. lower than the clearing point (Tc) of the polymer liquid crystal for 10 minutes. The sample was gradually cooled to room temperature to obtain Sample 1.
Sample 1 was observed for orientation, measured for haze value, and evaluated for light resistance test. The evaluation results are shown in Table 7.

  (Sample 2) The polymer liquid crystal obtained in Example 1 was injected into a wedge-shaped cell (product name “KCRS-07” manufactured by EHC) at a temperature higher than the clearing point (Tc) of the polymer liquid crystal under a nitrogen gas flow. (Tc-10) Annealing was performed at a temperature of 10 minutes for 10 minutes, followed by slow cooling to align the polymer liquid crystal. Interference fringes were observed using a polarizing microscope (manufactured by Olympus, product name: BX-51), and Δn was calculated from the spacing of the fringes. Δn at 30 ° C. and Δn change rate from 30 ° C. to 80 ° C. [(Δn at 30 ° C.) − (Δn at 80 ° C.) / (Δn at 30 ° C.)] are shown in Table 7. It was.

[Example 4] to [Example 24]
An optically anisotropic film was prepared and evaluated in the same manner as in Example 13 except that the polymer liquid crystal 1 was replaced with the polymer liquid crystals 2 to 12. For the polymer liquid crystal 12, the sample of the polymer liquid crystal-containing cell prepared in Example 12 was evaluated in the same manner as in Example 13. The results are shown in Table 7.
In Table 7, (1) means that Tc was not measured because of 80 ° C., and (2) indicates that measurement was impossible because of crystal at 80 ° C. (3) indicates that measurement was impossible due to the amorphous state at 80 ° C.

Provided are an optically anisotropic film having high transparency, excellent light resistance to blue laser light and little change in characteristics due to temperature, and a polymer liquid crystal suitable for adjusting the film. The optically anisotropic film of the present invention includes various retardation plates such as a positive A plate, a negative A plate, a positive C plate, a negative C plate, a twisted retardation film, a viewing angle widening film, a temperature compensation film, 1 / It can be used for a four-wave plate or a half-wave plate.

The entire contents of the specification, claims, and abstract of Japanese Patent Application No. 2007-22631 filed on August 31, 2007 are incorporated herein as the disclosure of the specification of the present invention. Is.

Claims (10)

A polymer liquid crystal comprising a copolymer containing two or more types of monomer units derived from the monomer represented by the following formula (1) and obtained by removing impurities by purification after polymerization.
CH ₂ = CR ¹ -COO- (CH ₂ ) _m- (CF ₂ ) _r- (CH ₂ ) _n- (O) _t -E ^1- (E ² ) _h- (E ³ ) _k -E ⁴ -R ² (1)
However, the symbols in the formula are as follows.
R ¹ : a hydrogen atom or a methyl group.
R ² : an alkyl group which may be substituted with a fluorine atom having 1 to 8 carbon atoms, an alkoxy group which may be substituted with a fluorine atom having 1 to 8 carbon atoms, or a fluorine atom.
E ¹ , E ² , E ³ , E ⁴ : each independently a 1,4-phenylene group or a trans-1,4-cyclohexylene group, and a hydrogen atom bonded to a carbon atom in the group is a carbon number It may be substituted with an alkyl group of 1 to 10, an alkoxy group of 1 to 10 carbon atoms, or a fluorine atom.
m: An integer of 0-6.
r: an integer of 0-6.
n: An integer of 0-6.
However, when r = 0, m + n is an integer of 10 or less.
t: 0 (when m + r + n = 0) or 1 (when m + r + n> 0).
h: 0 or 1.
k: 0 or 1.   2. The polymer liquid crystal according to claim 1, wherein the copolymer has a number average molecular weight of 3,000 to 50,000 and a content of impurities having a number average molecular weight of 1,000 or less is less than 0.5% by mass.   The copolymer comprises at least one monomer unit derived from a monomer having h + k of 1 in formula (1) and at least one monomer unit derived from a monomer having h + k of 2 in formula (1). Item 3. The polymer liquid crystal according to Item 1 or 2.   The polymer liquid crystal according to claim 1, wherein the copolymer has a glass transition point. Impurities having a number average molecular weight of 3,000 to 50,000 and a number average molecular weight of 1,000 or less are obtained by copolymerizing two or more types of monomers represented by the following formula (1) and then removing impurities. An optical anisotropy characterized in that after obtaining a polymer liquid crystal having a content of less than 1% by mass, the polymer liquid crystal is arranged on a substrate and the polymer liquid crystal is aligned in a state exhibiting a liquid crystal phase. A method for producing a membrane.
CH ₂ = CR ¹ -COO- (CH ₂ ) _m- (CF ₂ ) _r- (CH ₂ ) _n- (O) _t -E ^1- (E ² ) _h- (E ³ ) _k -E ⁴ -R ² (1)
However, the symbols in the formula are as follows.
R ¹ : a hydrogen atom or a methyl group.
R ² : an alkyl group which may be substituted with a fluorine atom having 1 to 8 carbon atoms, an alkoxy group which may be substituted with a fluorine atom having 1 to 8 carbon atoms, or a fluorine atom.
E ¹ , E ² , E ³ , E ⁴ : each independently a 1,4-phenylene group or a trans-1,4-cyclohexylene group, and a hydrogen atom bonded to a carbon atom in the group is a carbon number It may be substituted with an alkyl group of 1 to 10, an alkoxy group of 1 to 10 carbon atoms, or a fluorine atom.
m: An integer of 0-6.
r: an integer of 0-6.
n: An integer of 0-6.
However, when r = 0, m + n is an integer of 10 or less.
t: 0 (when m + r + n = 0) or 1 (when m + r + n> 0).
h: 0 or 1.
k: 0 or 1.   The copolymer comprises at least one monomer unit derived from a monomer having h + k of 1 in formula (1) and at least one monomer unit derived from a monomer having h + k of 2 in formula (1). Item 5. A method for producing an optically anisotropic film.   The method for producing an optically anisotropic film according to claim 5 or 6, wherein alignment is performed using a substrate subjected to alignment treatment as a base material.   An optically anisotropic film produced by the production method according to claim 5.   An optical element comprising the optically anisotropic film according to claim 8 and a support that supports the optically anisotropic film.   The optical element according to claim 9, which is used as a phase difference plate.