JP5750819B2 - Polymerizable liquid crystal composition - Google Patents

Description

  The present invention relates to a polymerizable liquid crystal composition used for producing an optical compensation film such as a liquid crystal display.

As a technique useful for improving the performance of a liquid crystal display, particularly a VA liquid crystal display, use of a biaxial retardation film using a polymerizable cholesteric material has been proposed (see Patent Documents 1 to 3). This biaxial film can be produced by applying a polymerizable cholesteric liquid crystal to a substrate and then polymerizing with polarized ultraviolet light.
In the biaxial retardation film, the front retardation (Re) and thickness direction retardation (Rth) defined as follows are important physical properties, the front retardation (Re) is 40 nm or more, and the thickness direction retardation. Rth is preferably 180 nm or more.

（式中、ｎｘ、ｎｙはそれぞれフィルム平面方向の屈折率を表し、nｚは厚み方向の屈折率を表し、ｄは厚みをを表す。）

(In the formula, nx and ny represent the refractive index in the film plane direction, nz represents the refractive index in the thickness direction, and d represents the thickness.)

(In the formula, nx and ny represent the refractive index in the film plane direction, nz represents the refractive index in the thickness direction, and d represents the thickness.)
Such a biaxial retardation film can be realized, for example, by using a dichroic photopolymerization initiator. However, the dichroic initiator has a problem that the material is limited because it is difficult to design the dichroic initiator in order to combine the performance of the dichroic and the polymerization initiator. In addition, it is extremely difficult to impart photopolymerization initiation performance that enables curing in the air (in the presence of oxygen) to the dichroic initiator, and the atmosphere with an inert gas such as nitrogen when irradiated with polarized UV light. Therefore, there is a problem that the manufacturing cost is increased, the tact time is increased, and the process margin is narrowed.

    On the other hand, it is possible to produce a biaxial film using a general polymerization initiator used in the technical field of radical photopolymerization instead of the dichroic initiator. If a photoinitiator that allows curing in air is selected, curing with polarized UV can be performed without substitution with an inert gas, but the performance as a biaxial film is not sufficient. There was a problem. In addition, a technique of adding 5 to 60% of a polymerizable liquid crystal compound having a carbon-carbon triple bond is disclosed in order to improve the front retardation of the biaxial film (see Patent Document 3). When this technique is used, when the compound having a carbon-carbon triple bond is not included, a front phase difference Re of only 8.5 nm is obtained, whereas a value of 30 nm or more can be obtained as the front phase difference Re. . However, a compound having a carbon-carbon triple bond has poor light resistance, and a film prepared by adding 5% or more of the compound has a problem that it is very easily yellowed by exposure to light.

JP 2005-513241 A Special table 2008-505369 Special table 2008-512504 gazette

  An object of the present invention is to provide a polymerizable liquid crystal composition provided as a material for a biaxial film, which can be cured in the air without substituting the atmosphere with an inert gas during ultraviolet irradiation, and has a frontal position. An object of the present invention is to provide a material capable of realizing the performance required as a biaxial film having a sufficiently large phase difference.

As a result of diligent studies to achieve the above object, it was found that an initiator, a light absorber, and a liquid crystal material should be selected so as to satisfy specific conditions, and the present invention has been completed.
The present invention relates to a polymerizable liquid crystal composition comprising a polymerizable liquid crystal compound, a chiral compound, a light absorber and a photopolymerization initiator, and the monofunctional polymerizable liquid crystal compound having two six-membered rings as the polymerizable liquid crystal compound. A polymerizable liquid crystal composition containing an acylphosphine oxide compound as the photopolymerization initiator, a light absorption band of the light absorber having a wavelength of 320 to 380 nm, and exhibiting a chiral nematic phase, and the polymerizable property An optical anisotropic body obtained by curing a liquid crystal composition is provided.

  The polymerizable liquid crystal composition of the present invention is produced by using a specific photopolymerization initiator, an absorbent, and a polymerizable liquid crystal compound, and can be polymerized in the air without using a dichroic initiator. Further, the front phase difference Re of the biaxial film can be increased. The polymerizable liquid crystal composition of the present invention does not need to replace the atmosphere at the time of UV curing with an inert gas, so the production process is not complicated, the degree of cure is hardly affected by the influence of residual oxygen, and biaxial film production The process margin at the time can be widened.

The light absorber contained in the polymerizable liquid crystal composition of the present invention has an absorption band at a wavelength of 280 to 400 nm, more preferably an absorption band at a wavelength of 300 to 390 nm, and an absorption band at 320 to 380 nm. It is particularly preferable to have it.
The specific structure of the light absorber preferably has a double bond in the molecule. As the double bond, a carbon-carbon double bond and a carbon-nitrogen double bond are preferable. Further, a molecule having good linearity is preferable. This light absorber may or may not exhibit liquid crystallinity.
Specifically, the general formula (PA)

（式中、Ｘ¹からＸ⁴はそれぞれ独立してフッ素原子、炭素原子数1〜18のアルキル基、アルコキシ基、アシル基、アルコキシカルボキシ基、炭素原子数2〜18のアルケニル基、又はアルケニルオキシ基を表し、ｌ及びｏはそれぞれ独立して１から５の整数を表し、ｍ及びｎはそれぞれ独立して１から４の整数を表し、Ｌ¹からＬ³はそれぞれ独立して単結合又は−CH＝CH−を表すが、Ｌ¹からＬ³の少なくとも二つは−CH＝CH−を表す。）で表される化合物が好ましく、一般式（PA-a）

Wherein X ¹ to X ⁴ are each independently a fluorine atom, an alkyl group having 1 to 18 carbon atoms, an alkoxy group, an acyl group, an alkoxycarboxy group, an alkenyl group having 2 to 18 carbon atoms, or alkenyloxy. And l and o each independently represents an integer of 1 to 5, m and n each independently represents an integer of 1 to 4, and L ¹ to L ³ each independently represents a single bond or- CH = CH—, wherein at least two of L ¹ to L ³ represent —CH═CH—) is preferred, and the compound represented by the general formula (PA-a)

（式中、Ｘ¹からＸ⁴はそれぞれ独立してフッ素原子、炭素原子数1〜18のアルキル基、アルコキシ基、アシル基、アルコキシカルボキシ基、炭素原子数2〜18のアルケニル基、又はアルケニルオキシ基を表し、ｌ及びｏはそれぞれ独立して１から５の整数を表し、ｍ及びｎはそれぞれ独立して１から４の整数を表す。）で表される化合物がより好ましく、
式（PA-１）

Wherein X ¹ to X ⁴ are each independently a fluorine atom, an alkyl group having 1 to 18 carbon atoms, an alkoxy group, an acyl group, an alkoxycarboxy group, an alkenyl group having 2 to 18 carbon atoms, or alkenyloxy. Wherein l and o each independently represents an integer of 1 to 5, and m and n each independently represents an integer of 1 to 4).
Formula (PA-1)

で表される化合物が特に好ましい。本化合物は360nm付近に吸収帯を有する。
光吸収剤の添加量は0.1~4%以下が好ましく、0.2~3%が更に好ましく、0.3~2%が特に好ましい。
光重合開始剤としてはアシルフォスフィンオキシド化合物を含有する。このような化合物として具体的には、一般式（RI-1）で表されるものが好ましい。

Is particularly preferred. This compound has an absorption band around 360 nm.
The addition amount of the light absorber is preferably 0.1 to 4% or less, more preferably 0.2 to 3%, and particularly preferably 0.3 to 2%.
The photopolymerization initiator contains an acyl phosphine oxide compound. Specifically, such a compound is preferably represented by the general formula (RI-1).

（式中、X^５からX^７はそれぞれ独立して炭素原子数２０以下のアルキル基、アリール基、アラルキル基、芳香環を表し、ｐ、ｑ、及びｒはそれぞれ独立して1〜4の整数を表し、X⁸は単結合、又は−CO−を表す。）
更に具体的には、式（RI-1a）及び式（RI-2a）を挙げることができる。

(Wherein X ⁵ to X ⁷ each independently represents an alkyl group having 20 or less carbon atoms, an aryl group, an aralkyl group or an aromatic ring, and p, q and r are each independently an integer of 1 to 4) X ⁸ represents a single bond or —CO—.)
More specifically, the formula (RI-1a) and the formula (RI-2a) can be exemplified.

  As the photopolymerization initiator, other photopolymerization initiators may be used in combination with the acylphosphine oxide compound. Examples of such photopolymerization initiators include “Irgacure-651”, “Irgacure-184D”, “Irgacure-1800”, “Irgacure-907”, “Irgacure-369”, “Irgacure OXE 01”, “Irgacure OXE 02” (Above, manufactured by Ciba Specialty Chemicals Co., Ltd.). In addition to the above, a polychromatic initiator having a difference in light absorption depending on the vibration plane of light may be used, and a general dichroic initiator may be used as the polychromatic initiator. However, from the viewpoint of availability and the number of initiator options, it is preferable to use an optically isotropic initiator other than the polychromatic initiator.

The addition amount of the polymerization initiator in the polymerizable liquid crystal composition is preferably 1 to 6%, more preferably 1 to 5%, and particularly preferably 3 to 5%. When the addition amount is small, the curability is deteriorated, and when the addition amount is large, the properties of the polymerizable liquid crystal composition as a liquid crystal are easily impaired.
The liquid crystal composition of the present invention comprises a polymerizable liquid crystal compound as an essential component, and the content thereof is 40 to 95%, more preferably 50 to 80%, particularly preferably 60 to 70 in the polymerizable liquid crystal composition. % Content is preferable.
As the polymerizable liquid crystal compound, a monofunctional polymerizable liquid crystal compound having two six-membered rings is an essential component. Such compounds include those represented by the general formula (I)

(Wherein Z ³ represents a hydrogen atom, a halogen atom, a cyano group or a hydrocarbon group having 1 to 20 carbon atoms, Z ⁴ represents a hydrogen atom or a methyl group, W ³ represents a single bond, —O—, -COO- or -OCO-, v represents an integer of 0 to 18, D and E are each independently 1,4-phenylene group, 1,4- A phenylene group, a 1,4-cyclohexylene group, a 1,4-cyclohexylene group in which one or two non-adjacent CH ₂ groups are substituted with an oxygen or sulfur atom, and a 1,4-cyclohexenylene group, The 1,4-phenylene group present in the formula may be substituted with one or more alkyl groups having 1 to 7 carbon atoms, alkoxy groups, alkanoyl groups, cyano groups or halogen atoms, and Y ⁶ and Y ⁷ are each independently represents a single _{bond, -CH 2 CH 2 -, -} CH 2 O -, - OCH 2 -, - COO -, - OCO -, - C≡C -, - CH = CH -, - CF = CF- _{, - (CH 2) 4 -} , - CH 2 CH 2 C H ₂ O-, -OCH ₂ CH ₂ CH _2- , -CH = CHCH ₂ CH _2- , -CH ₂ CH ₂ CH = CH-, -CH = CHCOO-, -OCOCH = CH-, -CH ₂ CH _{2 COO -, - CH 2 CH 2} OCO -, - COO CH 2 CH 2 - or -OCOCH ₂ CH ₂ - represents, Y ⁸ represents a single bond, -O -, - COO -, - OCO- or -CH = CHCOO -, But when W ³ represents a single bond, v represents an integer of 2 to 18).

The compound represented by the general formula (I) is useful because it has an effect of lowering the liquid crystal lower limit temperature, but the addition amount is preferably 5 to 60%, more preferably 10 to 40%, and more preferably 15 to 25%. Is particularly preferred. If the amount added is large, the heat resistance of the obtained biaxial film tends to be impaired.
The compound represented by the general formula (I) includes a compound having a liquid crystalline skeleton and a compound having a spacer between polymerizable functional groups.
In the general formula (I), the case where W ³ represents a substituent other than a single bond and v represents an integer of 2 to 18 corresponds to a compound having a spacer. Specifically, the following general formula (I-1 ) To general formula (I-9) are preferred.

(In the formula, X ¹ represents a hydrogen atom or a methyl group, S represents an integer of 1 to 20, and R represents an alkyl group having 1 to 20 carbon atoms.) From general formula (I-1) to general formula In (I-9), X ¹ is preferably a hydrogen atom, and S is preferably 3, 4, or 6. Among such compounds, the compound (I-5) having a cyano group as a terminal group is most preferable. When this compound is used, the front phase difference can be increased.
On the other hand, in the general formula (I), the case where W ³ represents a single bond and v represents 0 corresponds to a compound having no spacer, and specifically, the following structures are preferred.

(In the formula, a cyclohexane ring represents a transcyclohexane ring, a number represents a phase transition temperature, C represents a crystalline phase, N represents a nematic phase, S represents a smectic phase, and I represents an isotropic liquid phase.)
In addition to the monofunctional polymerizable liquid crystal compound having two six-membered rings as described above, a monofunctional liquid crystal compound having three or more six-membered rings may be contained. Such compounds include those represented by the general formula (II)

(Wherein Z ⁵ represents a hydrogen atom, a halogen atom, a cyano group or a hydrocarbon group having 1 to 20 carbon atoms, Z ⁶ represents a hydrogen atom or a methyl group, W ⁴ represents a single bond, —O—, -COO- or -OCO-, v represents an integer of 0 to 18, u represents 1 or 2, F, G and H are each independently a 1,4-phenylene group or a non-adjacent CH group. 1,4-phenylene group substituted with nitrogen, 1,4-cyclohexylene group, 1,4-cyclohexylene group in which one or two non-adjacent CH ₂ groups are substituted with oxygen or sulfur atoms, 1, Represents a 4-cyclohexenylene group, but the 1,4-phenylene group present in the formula is substituted by one or more alkyl groups, alkoxy groups, alkanoyl groups, cyano groups or halogen atoms having 1 to 7 carbon atoms. Y ⁸ and Y ⁹ are each independently a single bond, —CH ₂ CH ₂ —, —CH ₂ O—, —OCH ₂ —, —COO—, —OCO—, —C≡C—, — CH = CH-, -CF = CF -, - (CH 2) 4 -, - CH 2 CH 2 CH 2 O -, - OCH 2 CH 2 CH 2 -, - CH = CHCH 2 CH 2 -, - CH 2 CH 2 CH = CH -, - CH = CHCOO -, - OCOCH = CH -, - CH 2 CH 2 COO -, - CH 2 CH 2 OCO -, - COO CH 2 CH 2 - or -OCOCH ₂ CH ₂ - represents, Y ¹⁰ is Represents a single bond, —O—, —COO—, —OCO— or —CH═CHCOO—, and when W ⁴ represents a single bond, v represents an integer of 2 to 18.)
The amount of the compound represented by the general formula (II) is preferably 30% or less, more preferably 20% or less, and particularly preferably 10% or less.

The general formula (II) includes a compound having a liquid crystalline skeleton and a compound having a spacer between polymerizable functional groups, but W ⁴ represents a substituent other than a single bond, and v is an integer of 2 to 18 The case where it represents corresponds to a compound having a spacer, and specifically, compounds represented by the following general formulas (II-1) to (II-9) are preferable.

On the other hand, in the general formula (II), the case where W ⁴ represents a single bond and v represents 0 corresponds to a compound having no spacer, and specifically the following structures are preferred.

  The polymerizable liquid crystal composition of the present invention preferably contains a bifunctional material as the polymerizable liquid crystal compound from the viewpoint of ensuring the heat resistance and reliability of the film obtained by curing. Such compounds include general formula (III)

(Wherein P1 and P2 each represent a reactive functional group, Sp1 and Sp2 each independently represent a spacer group, i and j each independently represent 0 or 1, and MG represents a mesogenic group or Represents a mesogenic support group).
In the general formula (III), Sp1 and Sp2 each independently represent an alkylene group having 1 to 20 carbon atoms, and the alkylene group may be substituted with one or more halogen atoms or CN. independently one CH ₂ group or adjacent to each other each of the two or more CH ₂ groups not present in the form in which the oxygen atoms are not directly bonded to one another, -O -, - S -, - NH -, -N (CH ₃ )-, -CO-, -COO-, -OCO-, -OCOO-, -SCO-, -COS- or -C≡C- Formula (III-b)

(In the formula, A1, A2 and A3 are each independently 1,4-phenylene group, 1,4-cyclohexylene group, 1,4-cyclohexenyl group, tetrahydropyran-2,5-diyl group, 1, 3-dioxane-2,5-diyl group, tetrahydrothiopyran-2,5-diyl group, 1,4-bicyclo (2,2,2) octylene group, decahydronaphthalene-2,6-diyl group, pyridine- 2,5-diyl group, pyrimidine-2,5-diyl group, pyrazine-2,5-diyl group, 1,2,3,4-tetrahydronaphthalene-2,6-diyl group, 2,6-naphthylene group, Phenanthrene-2,7-diyl group, 9,10-dihydrophenanthrene-2,7-diyl group, 1,2,3,4,4a, 9,10a-octahydrophenanthrene 2,7-diyl group or fluorene 2, Represents a 7-diyl group, the 1,4-phenylene group, 1,2,3,4-tetrahydronaphthalene-2,6-diyl group, 2,6-naphthylene group, phenanthrene-2,7-diyl group, 9 , 10-Dihydrophenanthrene-2,7-diyl group 1,2,3,4,4a, 9,10a- octahydrophenanthrene 2,7-diyl group and fluorene 2,7-diyl group is 1 or more F as _{substituents, Cl, CF 3, OCF 3} , cyano Group, an alkyl group having 1 to 8 carbon atoms, an alkoxy group, an alkanoyl group, an alkanoyloxy group, an alkenyl group having 2 to 8 carbon atoms, an alkenyloxy group, an alkenoyl group or an alkenoyloxy group. , Z0, Z1, Z2 and Z3 are each independently -COO-, -OCO-, -CH ₂ CH _2- , -OCH _2- , -CH ₂ O-, -CH = CH-, -C≡C -, -CH = CHCOO-, -OCOCH = CH-, -CH ₂ CH ₂ COO-, -CH ₂ CH ₂ OCO-, -COO CH ₂ CH _2- , -OCOCH ₂ CH _2- , -CONH-,- NHCO- or a single bond, and n represents 0, 1, 2, or 3).
P1 and P2 are each independently the general formula (III-c) or general formula (III-d)

(Wherein R ²¹ , R ²² , R ²³ , R ³¹ , R ³² and R ³³ each independently represents a hydrogen atom, a halogen atom or an alkyl group having 1 to 5 carbon atoms, and k is 0 or 1) It is preferable to represent the substituent represented by.
Specifically, the compound represented by the general formula (III) is represented by the general formula (IV).

(In the formula, Z ⁷ and Z ⁸ represent a hydrogen atom or a methyl group, and I, J and K are each independently 1,4-phenylene group, 1,4 in which non-adjacent CH groups are substituted with nitrogen. A phenylene group, a 1,4-cyclohexylene group, a 1,4-cyclohexylene group or a 1,4-cyclohexenylene group in which one or two non-adjacent CH ₂ groups are substituted with an oxygen or sulfur atom. The 1,4-phenylene group present in the formula may be substituted with one or more alkyl groups having 1 to 7 carbon atoms, alkoxy groups, alkanoyl groups, cyano groups or halogen atoms, and m is from 0 to 3 W ¹ and W ² each independently represent a single bond, —O—, —COO— or —OCO—, and Y ¹ and Y ² each independently represent a single bond, —COO—, — _{OCO -, - CH 2 CH 2} COO -, - CH 2 CH 2 OCO -, - COO CH 2 CH 2 - or -OCOCH ₂ CH ₂ - represents, r and s integers of each independently 2-18 Represents The 1,4-phenylene group present therein may be substituted with one or more alkyl groups, alkoxy groups, alkanoyl groups, cyano groups, or halogen atoms having 1 to 7 carbon atoms. Is preferred.

  The compound represented by the general formula (IV) is effective for obtaining high heat resistance when formed into a film, but the addition amount is preferably 30 to 85%, more preferably 40 to 80%, ˜75% is particularly preferred.

  More specifically, the following can be mentioned.

(Wherein j, k, l and m each independently represent an integer of 2 to 18)
Among the compounds as described above, compounds represented by the general formula (IV-8) or (IV-9) are preferable. It is preferable to use a compound in which j and k are 3, 4 or 6, since the compound production cost and the liquid crystal temperature range can be appropriately set.

  Further, a discotic compound may be added to the polymerizable liquid crystal composition of the present invention. As such a discotic compound, a benzene derivative, a triphenylene derivative, a truxene derivative, a phthalocyanine derivative or a cyclohexane derivative is used as a mother nucleus at the center of the molecule, and a linear alkyl group, a linear alkoxy group, or a substituted benzoyloxy group is included. Preferably, the structure is a radially substituted side chain, and is represented by the general formula (V)

（式中、R⁵はそれぞれ独立して一般式（V-a）で表される置換基を表す。）

(In the formula, each R ⁵ independently represents a substituent represented by the general formula (Va).)

(In the formula, R ⁶ and R ⁷ each independently represent a hydrogen atom, a halogen atom or a methyl group, and R ⁸ represents an alkoxy group having 1 to 20 carbon atoms, and the hydrogen atom in the alkoxy group represents a general formula. (It may be substituted by a substituent represented by (Vb), general formula (Vc) or general formula (Vd).)

(Wherein R ⁸¹ , R ⁸² , R ⁸³ , R ⁸⁴ , R ⁸⁵ and R ⁸⁶ each independently represent a hydrogen atom, a halogen atom or an alkyl group having 1 to 5 carbon atoms, and n is 0 or 1) It is more preferable that at least one of R ⁸ in the general formula (Va) is substituted with a substituent represented by the general formula (Vb) or the general formula (Vc). It is particularly preferable that all of R ⁸ represent an alkoxy group substituted by a substituent represented by the general formula (Vb) or the general formula (Vc).

  Furthermore, the general formula (V-a) specifically represents the general formula (V-e).

（式中ｎは２〜９の整数を表す）で表される構造を有することが特に好ましい。
重合性液晶組成物には、塗布したときに良好なプラナー配向を迅速に得ることを目的として、一般式（VI）

It is particularly preferable to have a structure represented by the formula (wherein n represents an integer of 2 to 9).
The polymerizable liquid crystal composition has a general formula (VI) for the purpose of quickly obtaining good planar alignment when applied.

（式中、R¹、R²、R³及びR⁴はそれぞれ独立的に水素原子、ハロゲン原子又は炭素原子数1〜２０の炭化水素基を表し、該炭化水素基中の水素原子は１つ以上のハロゲン原子で置換されていても良い。）で表される繰り返し単位を有する重量平均分子量が１００以上である化合物を含有させることが好ましい。

(In the formula, R ¹ , R ² , R ³ and R ⁴ each independently represents a hydrogen atom, a halogen atom or a hydrocarbon group having 1 to 20 carbon atoms, and one hydrocarbon atom in the hydrocarbon group. It may be substituted with the above halogen atom.) It is preferable to contain a compound having a repeating unit represented by the following formula and having a weight average molecular weight of 100 or more.

Examples of the compound represented by the general formula (VI) include polyethylene, polypropylene, polyisobutylene, paraffin, liquid paraffin, chlorinated polypropylene, chlorinated paraffin, and chlorinated liquid paraffin. In addition to this, a compound in which a fluorine atom is introduced is also effective from the viewpoint of suppressing unevenness.
Among the compounds having a repeating unit represented by the general formula (VI), as a preferred structure, the formula (VI-a) to the formula (VI-f)

The compound which has a repeating unit represented by these is mentioned. Among these, structures represented by formulas (VI-a) to (VI-e) are more preferable, and structures represented by formulas (VI-a) and (VI-c) are particularly preferable. A copolymer obtained by copolymerizing two or more compounds having a repeating unit represented by formula (VI-a) to formula (VI-f) is also preferable. In this case, a copolymer having the formula (VI-a) and the formula (VI-b), a copolymer having the formula (VI-a) and the formula (VI-c), the formula (VI-a) and the formula ( More preferred are copolymers having VI-f) and copolymers having formulas (VI-a), (VI-b) and formula (VI-f), wherein formula (VI-a) and formula (VI Particularly preferred are copolymers having -b) and copolymers having the formulas (VI-a), (VI-b) and (VI-f).

  If the weight average molecular weight of the compound is too small, the effect of reducing the tilt angle is poor. If the weight average molecular weight is too large, the orientation is not stable for a long time, so there is an optimum range. Specifically, it is preferably 200 to 1000000, more preferably 300 to 100000, and particularly preferably 400 to 80000.

  Moreover, it is preferable to contain 0.01-5 mass% of this compound in a polymeric liquid crystal composition, It is more preferable to contain 0.05-2 mass%, Containing 0.1-1 mass% Is particularly preferred.

The polymerizable liquid crystal composition of the present invention contains a chiral compound for the purpose of obtaining a chiral nematic phase, and among the chiral compounds, compounds having a polymerizable functional group in the molecule are particularly preferred.
As the polymerizable functional group in the chiral compound, an acryloyloxy group is particularly preferable. The addition amount of the chiral compound needs to be appropriately adjusted depending on the helical induction force of the compound, but is preferably 12% or less.
Specific examples of the chiral compound include compounds of the formulas (a) to (g).

(Wherein n represents an integer of 2 to 12) Among these compounds, the compound (a) is preferred. In this case, n is most preferably 2 or 4 from the viewpoint of synthesis cost.

  A surfactant is preferably added to the polymerizable liquid crystal composition for the purpose of ensuring surface smoothness when it is applied. As the surfactant, there is no distinction between an ionic surfactant and a nonionic surfactant. Surfactants that can be included include alkyl carboxylates, alkyl phosphates, alkyl sulfonates, fluoroalkyl carboxylates, fluoroalkyl phosphates, fluoroalkyl sulfonates, polyoxyethylene derivatives, fluoro Examples thereof include alkylethylene oxide derivatives, polyethylene glycol derivatives, alkylammonium salts, fluoroalkylammonium salts, silicone derivatives and the like, and fluorine-containing surfactants and silicone derivatives are particularly preferable.

More specifically, “MEGAFAC F-110”, “MEGAFACCF-113”, “MEGAFAC F-120”, “MEGAFAC F-812”, “MEGAFAC F-142D”, “MEGAFAC F-144D”, “MEGAFAC F-” 150 "," MEGAFAC F-171 "," MEGAFACCF-173 "," MEGAFAC F-177 "," MEGAFAC F-183 "," MEGAFAC F-195 "," MEGAFAC F-824 "," MEGAFAC F-833 " , “MEGAFAC F-114”, “MEGAFAC F-410”, “MEGAFAC F-493”, “MEGAFAC F-494”, “MEGAFAC F-443”, “MEGAFAC F-444”, “MEGAFAC F-445”, "ME GAFAC F-446, MEGAFAC F-470, MEGAFAC F-471, MEGAFAC F-474, MEGAFAC F-475, MEGAFAC F-477, MEGAFAC F-478, MEGAFAC F-479, MEGAFAC F-480SF, MEGAFAC F-482, MEGAFAC F-483, MEGAFAC F-484, MEGAFAC F-486, MEGAFAC F-487, MEGAFAC F -489 "," MEGAFAC F-172D "," MEGAFAC F-178K "," MEGAFAC F-178RM "," MEGAFAC R-08 "," MEGAFAC R-30 "," MEGAFAC F-472SF "," MEGAFAC " "BL-20", "MEGAFAC R-61", "MEGAFAC R-90", "MEGAFAC ESM-1", "MEGAFAC MCF-350SF" (above, manufactured by DIC Corporation),

“Furgent 100”, “Furgent 100C”, “Furgent 110”, “Furgent 150”, “Furgent 150CH”, “Furgent A”, “Furgent 100A-K”, “Furgent 501”, "Factent 300", "Factent 310", "Factent 320", "Factent 400SW", "FTX-400P", "Factent 251", "Factent 215M", "Factent 212MH", "Footer Gent 250, Fategent 222F, Fategent 212D, FTX-218, FTX-209F, FTX-213F, FTX-233F, Fate 245F, FTX-208G ”,“ FTX-240G ”,“ FT -206D "," FTX-220D "," FTX-230D "," FTX-240D "," FTX-207S "," FTX-211S "," FTX-220S "," FTX-230S "," FTX-750FM " ”,“ FTX-730FM ”,“ FTX-730FL ”,“ FTX-710FS ”,“ FTX-710FM ”,“ FTX-710FL ”,“ FTX-750LL ”,“ FTX-730LS ”,“ FTX-730LM ”, "FTX-730LL", "FTX-710LL" (above, manufactured by Neos),

“BYK-300”, “BYK-302”, “BYK-306”, “BYK-307”, “BYK-310”, “BYK-315”, “BYK-320”, “BYK-322”, “BYK” -323 "," BYK-325 "," BYK-330 "," BYK-331 "," BYK-333 "," BYK-337 "," BYK-340 "," BYK-344 "," BYK-370 " ”,“ BYK-375 ”,“ BYK-377 ”,“ BYK-350 ”,“ BYK-352 ”,“ BYK-354 ”,“ BYK-355 ”,“ BYK-356 ”,“ BYK-358N ”, “BYK-361N”, “BYK-357”, “BYK-390”, “BYK-392”, “BYK-UV3500”, “BYK-UV3510”, “BYK-UV3570”, “B K-Silclean3700 "(manufactured by BYK Japan KK),

Examples include “TEGO Rad2100”, “TEGO Rad2200N”, “TEGO Rad2250”, “TEGO Rad2300”, “TEGO Rad2500”, “TEGO Rad2600”, “TEGO Rad2700” (manufactured by TEGO). The preferred addition amount of the surfactant varies depending on components other than the surfactant contained in the polymerizable liquid crystal composition, the use temperature, etc., but is contained in the polymerizable liquid crystal composition in an amount of 0.01 to 1% by mass. The content is preferably 0.02 to 0.5 mass%, more preferably 0.03 to 0.1 mass%. When the content is lower than 0.01% by mass, it is difficult to obtain the effect of reducing film thickness unevenness. The total content of the surfactant and the content of the compound having a weight average molecular weight of 100 or more having the repeating unit represented by the general formula (VI) is preferably 0.02 to 0.5% by mass, It is more preferable to contain 0.05-0.4 mass%, and it is especially preferable to contain 0.1-0.2 mass%.

  The lower limit temperature of the chiral nematic phase of the polymerizable liquid crystal composition is preferably lower than 40 ° C, more preferably lower than 30 ° C, and particularly preferably lower than 20 ° C. The upper limit temperature of the chiral nematic phase is preferably higher than 60 ° C, more preferably higher than 80 ° C, and particularly preferably higher than 100 ° C.

  The helical pitch of the chiral nematic phase is preferably designed so that the selective reflection of the chiral nematic phase is not in the visible light range. That is, it is preferable to design in the infrared region or the ultraviolet region, and it is particularly preferable to design in the ultraviolet region.

  The polymerizable liquid crystal composition of the present invention preferably contains 1000 to 15000 ppm of a polymerizable inhibitor. Examples of the polymerization inhibitor include hydroquinone, hydroquinone monoalkyl ethers, tert-butylcatechols, pyrogallols, thiophenols, nitro compounds, β-naphthylamines, β-naphthols, nitroso compounds and the like. More specific examples include methoxyphenol and 2,6-di-tert-butylphenol.

  The optical anisotropic body of the present invention can be obtained, for example, by supporting the polymerizable liquid crystal composition of the present invention on a substrate and aligning the material, followed by curing by irradiation with ultraviolet rays or electron beams. When producing a biaxial optical anisotropic body (film), it is preferable to irradiate polarized ultraviolet rays. In the case where the polymerizable liquid crystal composition is carried, a method in which the polymerizable liquid crystal composition is dissolved in a solvent, applied onto a substrate, and the solvent is volatilized can be exemplified. It is also possible to apply the polymerizable liquid crystal directly onto the substrate without dissolving it in the solvent. Suitable organic solvents include, for example, alkyl-substituted benzenes such as toluene, xylene, cumene, propylene glycol monomethyl ether acetate, butyl acetate, cyclohexanone, cyclopentanone and the like. Further, dimethylformamide, γ-butyrolactone, N-methylpyrrolidinone, methyl ethyl ketone, ethyl acetate and the like may be added to these solvents. Examples of the method for volatilizing the solvent include a method in which heating at 60 to 150 ° C., more preferably 80 to 120 ° C. is performed for 15 to 120 seconds, more preferably 30 to 90 seconds. In addition to this heating, vacuum drying can be combined. Examples of the application method include spin coating, die coating, extrusion coating, roll coating, wire bar coating, gravure coating, spray coating, dipping, and printing. As the substrate, either an inorganic material such as glass or an organic material such as a plastic film may be used. These substrates may be subjected to orientation treatment or may be used as they are. Alignment treatment includes rubbing treatment that rubs the substrate with a cloth, rubbing treatment after an organic thin film such as polyimide is formed on the substrate, or light that is irradiated with polarized ultraviolet light after the photo-alignment film is formed on the substrate. An alignment process etc. can be mentioned.

EXAMPLES Hereinafter, although an Example is given and this invention is further explained in full detail, this invention is not limited to these Examples. In addition,% represents mass%. The front phase difference Re was measured with RETS-100 manufactured by Otsuka Electronics (wavelength 589 nm). The phase difference in the thickness direction was determined by measuring the angle dependency of the phase difference with RETS-100 manufactured by Otsuka Electronics, and fitting with computer simulation software LCD-Master (manufactured by Shintech Co., Ltd.).
Reference Example 1 36.47% Liquid Crystalline Acrylate Compound of Preparation Formula (IV-9-a) for Polymerizable Liquid Crystal Composition

式（IV-9-b）の液晶性アクリレート化合物15.63%

Liquid crystalline acrylate compound of formula (IV-9-b) 15.63%

式（IV-8-a）の液晶性アクリレート化合物13.03%

Liquid crystalline acrylate compound of formula (IV-8-a) 13.03%

式（I-5-a）の液晶性アクリレート化合物21.71%

21.71% liquid crystalline acrylate compound of formula (I-5-a)

式（a-1）のキラルアクリレート化合物9.12%

9.12% of chiral acrylate compound of formula (a-1)

式（e-1）のキラルアクリレート化合物3.04%

3.04% chiral acrylate compound of formula (e-1)

光吸収剤（I-1）0.66%

Light absorber (I-1) 0.66%

流動パラフィン0.26%、p-メトキシフェノール0.09%からなる重合性液晶組成物（A）を調整した。光吸収剤（PA−１）は360nm付近に吸収帯を有する。図１に光吸収剤（PA-1）の分光スペクトルを示す。

A polymerizable liquid crystal composition (A) comprising 0.26% liquid paraffin and 0.09% p-methoxyphenol was prepared. The light absorber (PA-1) has an absorption band around 360 nm. FIG. 1 shows the spectrum of the light absorber (PA-1).

Example 1
Photopolymerization initiator 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide with 95.84% polymerizable liquid crystal composition (A) prepared in Reference Example 1 and an absorption band near 360 nm (Darocur TPO Ciba Specialty Chemicals) Made)

4.16%からなる重合性液晶組成物（B）を調整した。図２にDarocur TPOの吸収スペクトルを示す。

A polymerizable liquid crystal composition (B) composed of 4.16% was prepared. FIG. 2 shows the absorption spectrum of Darocur TPO.

Further, a polymerizable liquid crystal solution (B) composed of 40% polymerizable liquid crystal composition (B) and 60% cyclohexanone was prepared. This was spin-coated (1000 rotations / min, 30 seconds) on a glass substrate with a polyimide alignment film that had been rubbed. The spin-coated substrate was dried at 60 ° C. for 2 minutes and then allowed to stand at room temperature for 3 minutes to align the polymerizable liquid crystal in the planar orientation. The polymerizable liquid crystal composition layer thus obtained was irradiated with UV light generated from a high-pressure mercury lamp for 30 seconds in the air with polarized UV light (intensity 10 mW / cm ² ) having a wavelength of 360 nm through a polarizing filter and a bandpass filter. The polymerizable liquid crystal composition was cured. FIG. 3 shows an emission spectrum of a high pressure mercury lamp light source (before passing through a polarizing filter and a bandpass filter). The thickness of the obtained film was 3 μm. The resulting film was optically biaxial. The front phase difference Re was 62.7 nm. When this was heated at 230 ° C. for 1 hour, the front phase difference Re was 40.6 nm. Assuming that the phase difference before heating is 100%, the front phase difference Re is 64.8%. The haze of the film was 2.26%.

(Example 2)
The polymerizable liquid crystal solution (B) was spin-coated (1000 rotations / minute, 30 seconds) on a glass substrate with a polyimide alignment film that had been rubbed. The spin-coated substrate was dried at 60 ° C. for 2 minutes and then allowed to stand at room temperature for 3 minutes to align the polymerizable liquid crystal in the planar orientation. The polymerizable liquid crystal composition layer thus obtained was irradiated with UV light generated from a high-pressure mercury lamp for 30 seconds in the air with polarized UV light (intensity 10 mW / cm ² ) having a wavelength of 360 nm through a polarizing filter and a bandpass filter. The polymerizable liquid crystal composition was cured. Furthermore, UV light generated from the same high-pressure mercury lamp was irradiated with non-polarized UV (intensity 30 mW / cm2) in air for 27 seconds without passing through a bandpass filter and a polarizing filter, and additional curing was performed. The thickness of the obtained film was 3 μm. The resulting film was optically biaxial. The front phase difference Re was 57.5 nm. When this was heated at 230 ° C. for 1 hour, the front phase difference Re was 38.5 nm. Assuming that the phase difference before heating is 100%, the front phase difference Re is 67%. The haze was 1.54%.

(Example 3)
Photopolymerization initiator Darocur TPO (manufactured by Ciba Specialty Chemicals) 3.33%, Irgacure907 (manufactured by Ciba Specialty Chemicals) having a polymerizable liquid crystal composition (A) prepared in Reference Example 1 of 95.84% and an absorption band near 360 nm

0.83％からなる重合性液晶組成物（C）を調整した。図４にIrgacure 907の吸収スペクトルを示す。

A polymerizable liquid crystal composition (C) comprising 0.83% was prepared. FIG. 4 shows the absorption spectrum of Irgacure 907.

Further, a polymerizable liquid crystal solution (C) composed of 40% polymerizable liquid crystal composition (C) and 60% cyclohexanone was prepared. This was spin-coated (1000 rotations / min, 30 seconds) on a glass substrate with a polyimide alignment film that had been rubbed. The spin-coated substrate was dried at 60 ° C. for 2 minutes and then allowed to stand at room temperature for 3 minutes to align the polymerizable liquid crystal in the planar orientation. The polymerizable liquid crystal composition layer thus obtained was irradiated with UV light generated from a high-pressure mercury lamp for 30 seconds in the air with polarized UV light (intensity 10 mW / cm ² ) having a wavelength of 360 nm through a polarizing filter and a bandpass filter. The polymerizable liquid crystal composition was cured. The thickness of the obtained film was 3 μm. The resulting film was optically biaxial. The front phase difference Re was 56.7 nm. When this was heated at 230 ° C. for 1 hour, the front phase difference Re was 39.3 nm. Assuming that the phase difference before heating is 100%, the front phase difference Re is 69.3%. The haze of the film was 1.07%.

Example 4
The polymerizable liquid crystal solution (C) was spin-coated (1000 rotations / minute, 30 seconds) on a glass substrate with a polyimide alignment film that had been rubbed. The spin-coated substrate was dried at 60 ° C. for 2 minutes and then allowed to stand at room temperature for 3 minutes to align the polymerizable liquid crystal in the planar orientation. The polymerizable liquid crystal composition layer thus obtained was irradiated with UV light generated from a high-pressure mercury lamp for 30 seconds in the air with polarized UV light (intensity 10 mW / cm ² ) having a wavelength of 360 nm through a polarizing filter and a bandpass filter. The polymerizable liquid crystal composition was cured. Furthermore, UV light generated from the same high-pressure mercury lamp was irradiated with non-polarized UV (intensity 30 mW / cm2) in air for 27 seconds without passing through a bandpass filter and a polarizing filter, and additional curing was performed. The thickness of the obtained film was 3 μm. The resulting film was optically biaxial. The front phase difference Re was 54.7 nm. When this was heated at 230 ° C. for 1 hour, the front phase difference Re was 39.6 nm. Assuming that the phase difference before heating is 100%, the front phase difference Re is 72.4%. The haze was 0.67%.

(Example 5)
The polymerizable liquid crystal composition (A) prepared in Reference Example 1 is 95.84%, a photopolymerization initiator Darocur TPO (manufactured by Ciba Specialty Chemicals) 2.91% having an absorption band near 360 nm, Irgacure907 (manufactured by Ciba Specialty Chemicals) 1.25 % Polymerizable liquid crystal composition (D) was prepared.

Further, a polymerizable liquid crystal solution (D) composed of 40% polymerizable liquid crystal composition (D) and 60% cyclohexanone was prepared. This was spin-coated (1000 rotations / min, 30 seconds) on a glass substrate with a polyimide alignment film that had been rubbed. The spin-coated substrate was dried at 60 ° C. for 2 minutes and then allowed to stand at room temperature for 3 minutes to align the polymerizable liquid crystal in the planar orientation. The polymerizable liquid crystal composition layer thus obtained was irradiated with UV light generated from a high-pressure mercury lamp for 30 seconds in the air with polarized UV light (intensity 10 mW / cm ² ) having a wavelength of 360 nm through a polarizing filter and a bandpass filter. The polymerizable liquid crystal composition was cured. The thickness of the obtained film was 3 μm. The resulting film was optically biaxial. The front phase difference Re was 52.2 nm. When this was heated at 230 ° C. for 1 hour, the front phase difference Re was 38.3 nm. Assuming that the phase difference before heating is 100%, the front phase difference Re is 73.4%.

(Example 6)
The polymerizable liquid crystal solution (D) was spin-coated (1000 rotations / minute, 30 seconds) on a glass substrate with a polyimide alignment film that had been rubbed. The spin-coated substrate was dried at 60 ° C. for 2 minutes and then allowed to stand at room temperature for 3 minutes to align the polymerizable liquid crystal in the planar orientation. The polymerizable liquid crystal composition layer thus obtained was irradiated with UV light generated from a high-pressure mercury lamp for 30 seconds in the air with polarized UV light (intensity 10 mW / cm ² ) having a wavelength of 360 nm through a polarizing filter and a bandpass filter. The polymerizable liquid crystal composition was cured. Furthermore, UV light generated from the same high-pressure mercury lamp was irradiated with non-polarized UV (intensity 30 mW / cm2) in air for 27 seconds without passing through a bandpass filter and a polarizing filter, and additional curing was performed. The thickness of the obtained film was 3 μm. The resulting film was optically biaxial. The front phase difference Re was 49.8 nm. When this was heated at 230 ° C. for 1 hour, the front phase difference Re was 38.8 nm. Assuming that the phase difference before heating is 100%, the front phase difference Re is 77.9%.

(Example 7)
Photopolymerization initiator bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide (Irgacure 819 Ciba Specialty) with the polymerizable liquid crystal composition (A) prepared in Reference Example 1 having an absorption band near 360 nm of 95.84% (Chemicals)

4.16%からなる重合性液晶組成物（E）を調整した。図５にIrgacure 819の吸収スペクトルを示す。

A polymerizable liquid crystal composition (E) composed of 4.16% was prepared. FIG. 5 shows the absorption spectrum of Irgacure 819.

Further, a polymerizable liquid crystal solution (E) composed of 40% polymerizable liquid crystal composition (E) and 60% cyclohexanone was prepared. This was spin-coated (1000 rotations / min, 30 seconds) on a glass substrate with a polyimide alignment film that had been rubbed. The spin-coated substrate was dried at 60 ° C. for 2 minutes and then allowed to stand at room temperature for 3 minutes to align the polymerizable liquid crystal in the planar orientation. The polymerizable liquid crystal composition layer thus obtained was irradiated with UV light generated from a high-pressure mercury lamp for 30 seconds in the air with polarized UV light (intensity 10 mW / cm ² ) having a wavelength of 360 nm through a polarizing filter and a bandpass filter. The polymerizable liquid crystal composition was cured. The thickness of the obtained film was 3 μm. The resulting film was optically biaxial. The front phase difference Re was 59.7 nm. When this was heated at 230 ° C. for 1 hour, the front phase difference Re was 39.0 nm. Assuming that the phase difference before heating is 100%, the front phase difference Re is 65.3%. The haze of the film was 0.38%.

(Example 8)
The polymerizable liquid crystal solution (E) was spin-coated (1000 rotations / minute, 30 seconds) on a glass substrate with a polyimide alignment film subjected to rubbing treatment. The spin-coated substrate was dried at 60 ° C. for 2 minutes and then allowed to stand at room temperature for 3 minutes to align the polymerizable liquid crystal in the planar orientation. The polymerizable liquid crystal composition layer thus obtained was irradiated with UV light generated from a high-pressure mercury lamp for 30 seconds in the air with polarized UV light (intensity 10 mW / cm ² ) having a wavelength of 360 nm through a polarizing filter and a bandpass filter. The polymerizable liquid crystal composition was cured. Furthermore, UV light generated from the same high-pressure mercury lamp was irradiated with non-polarized UV (intensity 30 mW / cm2) in air for 27 seconds without passing through a bandpass filter and a polarizing filter, and additional curing was performed. The thickness of the obtained film was 3 μm. The resulting film was optically biaxial. The front phase difference Re was 54.5 nm. When this was heated at 230 ° C. for 1 hour, the front phase difference Re was 36.9 nm. Assuming that the phase difference before heating is 100%, the front phase difference Re is 67.7%. The haze was 0.12%.

Example 9
Polymerizable liquid crystal composition (A) prepared in Reference Example 1 is 95.84%, photopolymerization initiator Irgacure 819 having an absorption band near 360 nm (manufactured by Ciba Specialty Chemicals) 3.33%, Irgacure907 (manufactured by Ciba Specialty Chemicals) 0.83 % Polymerizable liquid crystal composition (F) was prepared.
Further, a polymerizable liquid crystal solution (F) composed of 40% polymerizable liquid crystal composition (F) and 60% cyclohexanone was prepared. This was spin-coated (1000 rotations / min, 30 seconds) on a glass substrate with a polyimide alignment film that had been rubbed. The spin-coated substrate was dried at 60 ° C. for 2 minutes and then allowed to stand at room temperature for 3 minutes to align the polymerizable liquid crystal in the planar orientation. The polymerizable liquid crystal composition layer thus obtained was irradiated with UV light generated from a high-pressure mercury lamp for 30 seconds in the air with polarized UV light (intensity 10 mW / cm ² ) having a wavelength of 360 nm through a polarizing filter and a bandpass filter. The polymerizable liquid crystal composition was cured. The thickness of the obtained film was 3 μm. The resulting film was optically biaxial. The front phase difference Re was 60.2 nm. When this was heated at 230 ° C. for 1 hour, the front phase difference Re was 40.2 nm. When the phase difference before heating was 100%, the front phase difference Re was 66.8%. The haze of the film was 0.57%.

(Example 10)
The polymerizable liquid crystal solution (F) was spin coated (1000 rotations / minute, 30 seconds) on a glass substrate with a polyimide alignment film that had been rubbed. The spin-coated substrate was dried at 60 ° C. for 2 minutes and then allowed to stand at room temperature for 3 minutes to align the polymerizable liquid crystal in the planar orientation. The polymerizable liquid crystal composition layer thus obtained was irradiated with UV light generated from a high-pressure mercury lamp for 30 seconds in the air with polarized UV light (intensity 10 mW / cm ² ) having a wavelength of 360 nm through a polarizing filter and a bandpass filter. The polymerizable liquid crystal composition was cured. Furthermore, UV light generated from the same high-pressure mercury lamp was irradiated with non-polarized UV (intensity 30 mW / cm2) in air for 27 seconds without passing through a bandpass filter and a polarizing filter, and additional curing was performed. The thickness of the obtained film was 3 μm. The resulting film was optically biaxial. The front phase difference Re was 57.0 nm. When this was heated at 230 ° C. for 1 hour, the front phase difference Re was 43.0 nm. Assuming that the phase difference before heating is 100%, the front phase difference Re is 75.4%. The haze was 1.64%.

(Example 11)
The polymerizable liquid crystal composition (A) prepared in Reference Example 1 is 95.84%, a photopolymerization initiator Irgacure 819 (manufactured by Ciba Specialty Chemicals) with an absorption band near 360 nm 2.91%, Irgacure907 (manufactured by Ciba Specialty Chemicals) 1.25 % Polymerizable liquid crystal composition (G) was prepared.
Furthermore, a polymerizable liquid crystal solution (G) comprising 40% of a polymerizable liquid crystal composition (G) and 60% of cyclohexanone was prepared. This was spin-coated (1000 rotations / min, 30 seconds) on a glass substrate with a polyimide alignment film that had been rubbed. The spin-coated substrate was dried at 60 ° C. for 2 minutes and then allowed to stand at room temperature for 3 minutes to align the polymerizable liquid crystal in the planar orientation. The polymerizable liquid crystal composition layer thus obtained was irradiated with UV light generated from a high-pressure mercury lamp for 30 seconds in the air with polarized UV light (intensity 10 mW / cm ² ) having a wavelength of 360 nm through a polarizing filter and a bandpass filter. The polymerizable liquid crystal composition was cured. The thickness of the obtained film was 3 μm. The resulting film was optically biaxial. The front phase difference Re was 52.4 nm. When this was heated at 230 ° C. for 1 hour, the front phase difference Re was 36.9 nm. Assuming that the phase difference before heating is 100%, the front phase difference Re is 70.4%.

(Example 12)
The polymerizable liquid crystal solution (G) was spin-coated (1000 rotations / minute, 30 seconds) on a glass substrate with a polyimide alignment film that had been rubbed. The spin-coated substrate was dried at 60 ° C. for 2 minutes and then allowed to stand at room temperature for 3 minutes to align the polymerizable liquid crystal in the planar orientation. The polymerizable liquid crystal composition layer thus obtained was irradiated with UV light generated from a high-pressure mercury lamp for 30 seconds in the air with polarized UV light (intensity 10 mW / cm ² ) having a wavelength of 360 nm through a polarizing filter and a bandpass filter. The polymerizable liquid crystal composition was cured. Furthermore, UV light generated from the same high-pressure mercury lamp was irradiated with non-polarized UV (intensity 30 mW / cm2) in air for 27 seconds without passing through a bandpass filter and a polarizing filter, and additional curing was performed. The thickness of the obtained film was 3 μm. The resulting film was optically biaxial. The front phase difference Re was 57.0 nm. When this was heated at 230 ° C. for 1 hour, the front phase difference Re was 38.5 nm. Assuming that the phase difference before heating is 100%, the front phase difference Re is 70.4%.

(Example 13)
The polymerizable liquid crystal composition (A) prepared in Reference Example 1 is 95.84%, a photopolymerization initiator Irgacure 819 having an absorption band near 360 nm (manufactured by Ciba Specialty Chemicals) 3.33%, Irgacure-369 (manufactured by Ciba Specialty Chemicals) )

0.83％からなる重合性液晶組成物（H）を調整した。
更に重合性液晶組成物（H）40%、シクロヘキサノン60%からなる重合性液晶溶液（H）を調製した。これをラビング処理を施したポリイミド配向膜付きのガラス基板にスピンコート（1000回転/分、30秒）した。スピンコートした基板を60℃で2分間乾燥した後、3分間室温で放置し、重合性液晶をプラナー配向させた。このようにして得られた重合性液晶組成物層に、高圧水銀ランプから発生する紫外線を偏光フィルター、バンドパスフィルターを通して波長360nmの偏光UV（強度10mW/cm²）を空気中で30秒照射して重合性液晶組成物を硬化させた。得られた膜の厚みは3μｍであった。得られた膜は光学的に二軸性であった。正面位相差Reは56.3nmであった。これを230℃で1時間加熱したところ、正面位相差Reは37.1nmになった。加熱前の位相差を100%とすると、正面位相差Reは65.9%になった。

A polymerizable liquid crystal composition (H) comprising 0.83% was prepared.
Further, a polymerizable liquid crystal solution (H) composed of 40% polymerizable liquid crystal composition (H) and 60% cyclohexanone was prepared. This was spin-coated (1000 rotations / min, 30 seconds) on a glass substrate with a polyimide alignment film that had been rubbed. The spin-coated substrate was dried at 60 ° C. for 2 minutes and then allowed to stand at room temperature for 3 minutes to align the polymerizable liquid crystal in the planar orientation. The polymerizable liquid crystal composition layer thus obtained was irradiated with UV light generated from a high-pressure mercury lamp for 30 seconds in the air with polarized UV light (intensity 10 mW / cm ² ) having a wavelength of 360 nm through a polarizing filter and a bandpass filter. The polymerizable liquid crystal composition was cured. The thickness of the obtained film was 3 μm. The resulting film was optically biaxial. The front phase difference Re was 56.3 nm. When this was heated at 230 ° C. for 1 hour, the front phase difference Re was 37.1 nm. Assuming that the phase difference before heating is 100%, the front phase difference Re is 65.9%.

(Example 14)
The polymerizable liquid crystal solution (H) was spin-coated (1000 rotations / minute, 30 seconds) on a glass substrate with a polyimide alignment film that had been rubbed. The spin-coated substrate was dried at 60 ° C. for 2 minutes and then allowed to stand at room temperature for 3 minutes to align the polymerizable liquid crystal in the planar orientation. The polymerizable liquid crystal composition layer thus obtained was irradiated with UV light generated from a high-pressure mercury lamp for 30 seconds in the air with polarized UV light (intensity 10 mW / cm ² ) having a wavelength of 360 nm through a polarizing filter and a bandpass filter. The polymerizable liquid crystal composition was cured. Furthermore, UV light generated from the same high-pressure mercury lamp was irradiated with non-polarized UV (intensity 30 mW / cm2) in air for 27 seconds without passing through a bandpass filter and a polarizing filter, and additional curing was performed. The thickness of the obtained film was 3 μm. The resulting film was optically biaxial. The front phase difference Re was 49.5 nm. When this was heated at 230 ° C. for 1 hour, the front phase difference Re was 35.5 nm. Assuming that the phase difference before heating is 100%, the front phase difference Re is 71.7%.

(Example 15)
The polymerizable liquid crystal composition (A) prepared in Reference Example 1 is 95.84%, photopolymerization initiator Darocur TPO (manufactured by Ciba Specialty Chemicals) having an absorption band near 360 nm, 3.33%, Irgacure OXE01 (manufactured by Ciba Specialty Chemicals)

0.83%からなる重合性液晶組成物（I）を調整した。図６にIrgacure OXE01の吸収スペクトルを示す。

A polymerizable liquid crystal composition (I) comprising 0.83% was prepared. FIG. 6 shows the absorption spectrum of Irgacure OXE01.

Further, a polymerizable liquid crystal solution (E) composed of 40% polymerizable liquid crystal composition (I) and 60% cyclohexanone was prepared. This was spin-coated (1000 rotations / min, 30 seconds) on a glass substrate with a polyimide alignment film that had been rubbed. The spin-coated substrate was dried at 60 ° C. for 2 minutes and then allowed to stand at room temperature for 3 minutes to align the polymerizable liquid crystal in the planar orientation. The polymerizable liquid crystal composition layer thus obtained was irradiated with UV light generated from a high-pressure mercury lamp for 30 seconds in the air with polarized UV light (intensity 10 mW / cm ² ) having a wavelength of 360 nm through a polarizing filter and a bandpass filter. The polymerizable liquid crystal composition was cured. The thickness of the obtained film was 3 μm. The resulting film was optically biaxial. The front phase difference Re was 52.9 nm.

(Example 16)
The polymerizable liquid crystal composition (A) prepared in Reference Example 1 is 95.84%, photopolymerization initiator Darocur TPO (manufactured by Ciba Specialty Chemicals) having an absorption band near 360 nm, 3.33%, Irgacure OXE02 (manufactured by Ciba Specialty Chemicals)

A polymerizable liquid crystal composition (J) consisting of 4.16% was prepared. FIG. 7 shows the absorption spectrum of Irgacure OXE02.

Further, a polymerizable liquid crystal solution (E) composed of 40% polymerizable liquid crystal composition (J) and 60% cyclohexanone was prepared. This was spin-coated (1000 rotations / min, 30 seconds) on a glass substrate with a polyimide alignment film that had been rubbed. The spin-coated substrate was dried at 60 ° C. for 2 minutes and then allowed to stand at room temperature for 3 minutes to align the polymerizable liquid crystal in the planar orientation. The polymerizable liquid crystal composition layer thus obtained was irradiated with UV light generated from a high-pressure mercury lamp for 30 seconds in the air with polarized UV light (intensity 10 mW / cm ² ) having a wavelength of 360 nm through a polarizing filter and a bandpass filter. The polymerizable liquid crystal composition was cured. The thickness of the obtained film was 3 μm. The resulting film was optically biaxial. The front phase difference Re was 47.0 nm.

( Reference Example 2 )
Polymerizable liquid crystal composition (K) comprising the polymerizable liquid crystal composition (A) prepared in Reference Example 1 with 95.84% and a photopolymerization initiator Irgacure OXE01 (manufactured by Ciba Specialty Chemicals) having an absorption band near 360 nm of 4.16% Adjusted.
Further, a polymerizable liquid crystal solution (K) composed of 40% polymerizable liquid crystal composition (K) and 60% cyclohexanone was prepared. This was spin-coated (1000 rotations / min, 30 seconds) on a glass substrate with a polyimide alignment film that had been rubbed. The spin-coated substrate was dried at 60 ° C. for 2 minutes and then allowed to stand at room temperature for 3 minutes to align the polymerizable liquid crystal in the planar orientation. The polymerizable liquid crystal composition layer thus obtained was irradiated with UV light generated from a high-pressure mercury lamp for 30 seconds in the air with polarized UV light (intensity 10 mW / cm ² ) having a wavelength of 360 nm through a polarizing filter and a bandpass filter. The polymerizable liquid crystal composition was cured. The thickness of the obtained film was 3 μm. The resulting film was optically biaxial. The front phase difference Re was 40.6 nm. When this was heated at 230 ° C. for 1 hour, the front phase difference Re was 30.5 nm. Assuming that the phase difference before heating is 100%, the front phase difference Re is 75.1%. The haze was 0.28%.

( Reference Example 3 )
The polymerizable liquid crystal solution (K) was spin-coated (1000 rotations / minute, 30 seconds) on a glass substrate with a polyimide alignment film subjected to rubbing treatment. The spin-coated substrate was dried at 60 ° C. for 2 minutes and then allowed to stand at room temperature for 3 minutes to align the polymerizable liquid crystal in the planar orientation. The polymerizable liquid crystal composition layer thus obtained was irradiated with UV light generated from a high-pressure mercury lamp for 30 seconds in the air with polarized UV light (intensity 10 mW / cm ² ) having a wavelength of 360 nm through a polarizing filter and a bandpass filter. The polymerizable liquid crystal composition was cured. Furthermore, UV light generated from the same high-pressure mercury lamp was irradiated with non-polarized UV (intensity 30 mW / cm2) in air for 27 seconds without passing through a bandpass filter and a polarizing filter, and additional curing was performed. The thickness of the obtained film was 3 μm. The resulting film was optically biaxial. The front phase difference Re was 37.8 nm. When this was heated at 230 ° C. for 1 hour, the front phase difference Re was 28.6 nm. When the phase difference before heating was 100%, the front phase difference Re was 75.7%. The haze was 0.17%.

式（IV-9-b）の液晶性アクリレート化合物15.74%

Liquid crystalline acrylate compound of formula (IV-9-b) 15.74%

式（IV-8-a）の液晶性アクリレート化合物13.11%

Liquid crystalline acrylate compound of formula (IV-8-a) 13.11%

式（I-5-a）の液晶性アクリレート化合物21.85%

21.85% liquid crystalline acrylate compound of formula (I-5-a)

式（a-1）のキラルアクリレート化合物9.18%

9.18% chiral acrylate compound of formula (a-1)

式（e-1）のキラルアクリレート化合物3.06%

3.06% chiral acrylate compound of formula (e-1)

流動パラフィン0.26%、p-メトキシフェノール0.09%からなる重合性液晶組成物（L）を調整した。重合性液晶組成物（L）が95.84%、360nm付近に吸収帯を持つ光重合開始剤Irgacure 819（チバスペシャリティケミカルズ社製）3.33%、Irgacure907（チバスペシャリティケミカルズ社製）0.83％からなる重合性液晶組成物（M）を調整した。

A polymerizable liquid crystal composition (L) comprising liquid paraffin 0.26% and p-methoxyphenol 0.09% was prepared. Polymerizable liquid crystal composed of 95.84% polymerizable liquid crystal composition (L), photopolymerization initiator Irgacure 819 (manufactured by Ciba Specialty Chemicals) having an absorption band near 360 nm, 3.33%, and Irgacure907 (manufactured by Ciba Specialty Chemicals) 0.83% Composition (M) was prepared.

Further, a polymerizable liquid crystal solution (M) composed of 40% polymerizable liquid crystal composition (M) and 60% cyclohexanone was prepared. This was spin-coated (1000 rotations / min, 30 seconds) on a glass substrate with a polyimide alignment film that had been rubbed. The spin-coated substrate was dried at 60 ° C. for 2 minutes and then allowed to stand at room temperature for 3 minutes to align the polymerizable liquid crystal in the planar orientation. The polymerizable liquid crystal composition layer thus obtained was irradiated with UV light generated from a high-pressure mercury lamp for 30 seconds in the air with polarized UV light (intensity 10 mW / cm ² ) having a wavelength of 360 nm through a polarizing filter and a bandpass filter. The polymerizable liquid crystal composition was cured. The thickness of the obtained film was 3 μm. The resulting film was optically biaxial. The front phase difference Re was 18.0 nm.
(Comparative Example 2)
95.84% of the polymerizable liquid crystal composition (A) prepared in Reference Example 1, a dichroic initiator represented by the formula (PI-1)

4.16%からなる重合性液晶組成物（N）を調整した。

A polymerizable liquid crystal composition (N) composed of 4.16% was prepared.

Further, a polymerizable liquid crystal solution (N) composed of 40% polymerizable liquid crystal composition (N) and 60% cyclohexanone was prepared. This was spin-coated (1000 rotations / min, 30 seconds) on a glass substrate with a polyimide alignment film that had been rubbed. The spin-coated substrate was dried at 60 ° C. for 2 minutes and then allowed to stand at room temperature for 3 minutes to align the polymerizable liquid crystal in the planar orientation. The polymerizable liquid crystal composition layer thus obtained was irradiated with UV light generated from a high-pressure mercury lamp with polarized UV light (intensity 10 mW / cm ² ) for 30 seconds in air through a polarizing filter and a bandpass filter. However, it did not cure. Thus, it is clear that the dichroic initiator cannot be cured in air.

  The above results are summarized in Table 1. From these results, it can be seen that the front phase difference can be increased even with the same thickness when the polymerizable liquid crystal composition of the present invention is used.

Spectral spectrum of light absorber (PA-1) (acetonitrile solution, 10ppm, optical path length 1cm) Emission spectrum of high-pressure mercury lamp (before passing through polarizing filter and bandpass filter) Spectral spectrum of photopolymerization initiator Darocur TPO (acetonitrile solution, 20 ppm, optical path length 1 cm) Spectral spectrum of photopolymerization initiator Irgacure 907 (acetonitrile solution, 20 ppm, optical path length 1 cm) Spectral spectrum of photopolymerization initiator Irgacure 819 (acetonitrile solution, 20 ppm, optical path length 1 cm) Spectral spectrum of photopolymerization initiator Irgacure OXE01 (acetonitrile solution, 20 ppm, optical path length 1 cm) Spectral spectrum of photopolymerization initiator Irgacure OXE02 (acetonitrile solution, 20 ppm, optical path length 1 cm)

Claims (10)

In a polymerizable liquid crystal composition containing a polymerizable liquid crystal compound, a chiral compound, a light absorber and a photopolymerization initiator, the polymerizable liquid crystal compound contains a monofunctional polymerizable liquid crystal compound having two six-membered rings, The photopolymerization initiator contains an acylphosphine oxide compound, the light absorber has a light absorption band having a wavelength of 280 to 400 nm, and is represented by the general formula (PA)

Wherein X ¹ to X ⁴ are each independently a fluorine atom, an alkyl group having 1 to 18 carbon atoms, an alkoxy group, an acyl group, an alkoxycarboxy group, an alkenyl group having 2 to 18 carbon atoms, or alkenyloxy. And l and o each independently represents an integer of 1 to 5, m and n each independently represents an integer of 1 to 4, and L ¹ to L ³ each independently represents a single bond or- A polymerizable liquid crystal composition containing a compound represented by CH = CH-, wherein at least two of L ¹ to L ³ represent -CH = CH-) and exhibiting a chiral nematic phase. 2. The polymerizable liquid crystal composition according to claim 1, which is cured by ultraviolet rays having a wavelength of 280 to 400 nm in air. The polymerizable liquid crystal composition according to claim 1, which has a double bond in the skeleton of the light absorber. Acylphosphine oxide compounds are represented by the general formula (RI-1)

(Wherein X ⁵ to X ⁷ each independently represents an alkyl group having 20 or less carbon atoms, an aryl group, an aralkyl group or an aromatic ring, and p, q and r each independently represents an integer of 1 to 4) It represents, X ⁸ is a single bond, or a polymerizable liquid crystal composition according to any one of claims 1 to 3, represented -CO- and represented.) the. The polymerizable liquid crystal composition according to any one of claims 1 to 4 chiral compound has a polymerizable functional group in the molecule. Monofunctional polymerizable liquid crystal compounds having two 6-membered rings are represented by the general formula (I)

(Wherein Z ³ represents a hydrogen atom, a halogen atom, a cyano group or a hydrocarbon group having 1 to 20 carbon atoms, Z ⁴ represents a hydrogen atom or a methyl group, W ³ represents a single bond, —O—, -COO- or -OCO-, v represents an integer of 0 to 18, D and E are each independently 1,4-phenylene group, 1,4- A phenylene group, a 1,4-cyclohexylene group, a 1,4-cyclohexylene group in which one or two non-adjacent CH ₂ groups are substituted with an oxygen or sulfur atom, and a 1,4-cyclohexenylene group, The 1,4-phenylene group present in the formula may be substituted with one or more alkyl groups having 1 to 7 carbon atoms, alkoxy groups, alkanoyl groups, cyano groups or halogen atoms, and Y ⁶ and Y ⁷ are each independently represents a single _{bond, -CH 2 CH 2 -, -} CH 2 O -, - OCH 2 -, - COO -, - OCO -, - C≡C -, - CH = CH -, - CF = CF- _{, - (CH 2) 4 -} , - CH 2 CH 2 C H ₂ O-, -OCH ₂ CH ₂ CH _2- , -CH = CHCH ₂ CH _2- , -CH ₂ CH ₂ CH = CH-, -CH = CHCOO-, -OCOCH = CH-, -CH ₂ CH _{2 COO -, - CH 2 CH 2} OCO -, - COO CH 2 CH 2 - or -OCOCH ₂ CH ₂ - represents, Y ⁸ represents a single bond, -O -, - COO -, - OCO- or -CH = CHCOO - it represents a, W ³ is a polymerizable liquid crystal composition according to any one of claims 1-5 when v is represented by representing) an integer of 2 to 18 represents a single bond.. General formula (III) as a polymerizable liquid crystal compound

(Wherein P1 and P2 each represent a reactive functional group, Sp1 and Sp2 each independently represent a spacer group, i and j each independently represent 0 or 1, and MG represents a mesogenic group or Represents a mesogenic support group.)
In the polymerizable liquid crystal composition according to any one of claims 1 to 6 represented. In the general formula (III), Sp1 and Sp2 each independently represent an alkylene group having 1 to 20 carbon atoms, and the alkylene group may be substituted with one or more halogen atoms or CN. independently one CH ₂ group or adjacent to each other each of the two or more CH ₂ groups not present in the form in which the oxygen atoms are not directly bonded to one another, -O -, - S -, - NH -, -N (CH ₃ )-, -CO-, -COO-, -OCO-, -OCOO-, -SCO-, -COS- or -C≡C- Formula (III-b)

(In the formula, A1, A2 and A3 are each independently 1,4-phenylene group, 1,4-cyclohexylene group, 1,4-cyclohexenyl group, tetrahydropyran-2,5-diyl group, 1, 3-dioxane-2,5-diyl group, tetrahydrothiopyran-2,5-diyl group, 1,4-bicyclo (2,2,2) octylene group, decahydronaphthalene-2,6-diyl group, pyridine- 2,5-diyl group, pyrimidine-2,5-diyl group, pyrazine-2,5-diyl group, 1,2,3,4-tetrahydronaphthalene-2,6-diyl group, 2,6-naphthylene group, Phenanthrene-2,7-diyl group, 9,10-dihydrophenanthrene-2,7-diyl group, 1,2,3,4,4a, 9,10a-octahydrophenanthrene 2,7-diyl group or fluorene 2, Represents a 7-diyl group, the 1,4-phenylene group, 1,2,3,4-tetrahydronaphthalene-2,6-diyl group, 2,6-naphthylene group, phenanthrene-2,7-diyl group, 9 , 10-Dihydrophenanthrene-2,7-diyl group 1,2,3,4,4a, 9,10a- octahydrophenanthrene 2,7-diyl group and fluorene 2,7-diyl group is 1 or more F as _{substituents, Cl, CF 3, OCF 3} , cyano Group, an alkyl group having 1 to 8 carbon atoms, an alkoxy group, an alkanoyl group, an alkanoyloxy group, an alkenyl group having 2 to 8 carbon atoms, an alkenyloxy group, an alkenoyl group or an alkenoyloxy group. , Z0, Z1, Z2 and Z3 are each independently -COO-, -OCO-, -CH ₂ CH _2- , -OCH _2- , -CH ₂ O-, -CH = CH-, -C≡C -, -CH = CHCOO-, -OCOCH = CH-, -CH ₂ CH ₂ COO-, -CH ₂ CH ₂ OCO-, -COO CH ₂ CH _2- , -OCOCH ₂ CH _2- , -CONH-,- NHCO- or a single bond, n represents 0, 1, 2, or 3), and P1 and P2 are each independently represented by the general formula (III-c) or the general formula ( III-d)

(Wherein R ²¹ , R ²² , R ²³ , R ³¹ , R ³² and R ³³ each independently represents a hydrogen atom, a halogen atom or an alkyl group having 1 to 5 carbon atoms, and k is 0 or 1) The polymerizable liquid crystal composition according to claim 7 , which represents a substituent represented by: The compound represented by formula (III) is represented by formula (IV)

(In the formula, Z ⁷ and Z ⁸ each independently represent a hydrogen atom or a methyl group; I, J and K are each independently a 1,4-phenylene group or a non-adjacent CH group substituted with nitrogen. 1,4-phenylene group, 1,4-cyclohexylene group, 1,4-cyclohexylene group in which one or two non-adjacent CH ₂ groups are substituted with oxygen or sulfur atoms, 1,4-cyclohexenylene Represents a group, and the 1,4-phenylene group present in the formula may be substituted with one or more alkyl group, alkoxy group, alkanoyl group, cyano group or halogen atom having 1 to 7 carbon atoms, m Represents an integer of 0 to 3, W ¹ and W ² each independently represent a single bond, —O—, —COO— or —OCO—, Y ¹ and Y ² each independently represent a single bond, — COO-, -OCO-, -CH ₂ CH ₂ COO-, -CH ₂ CH ₂ OCO-, -COO CH ₂ CH _2- , -OCOCH ₂ CH _2- , and r and s are each independently 2 to 2 An integer of 18 The 1,4-phenylene group present in the formula may be substituted with one or more alkyl groups, alkoxy groups, alkanoyl groups, cyano groups, or halogen atoms having 1 to 7 carbon atoms. The polymerizable liquid crystal composition according to claim 7 , which is a represented compound. Optically anisotropic medium obtained by curing any of the polymerizable liquid crystal composition of claims 1-9, wherein.

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