JP4834903B2 - Polymerizable liquid crystal composition - Google Patents

Description

(式中、X¹、X²は各々独立的に水素原子またはメチル基を表し、m、nは各々独立的に2〜10の整数を表し、Y¹、Y²は各々独立的に炭素原子数1〜5のアルキル基、アルコキシ基、ハロゲン原子を表し、p、qは各々独立的に0〜4の整数を表す)で表される化合物のうち、mとnの和が異なる少なくとも2種の化合物を含有し、液晶下限温度が40℃以下であることを特徴とする重合性液晶組成物。発明2、一般式(I)で表される化合物を少なくとも90質量%以上含有することを特徴とする発明1記載の重合性液晶組成物。発明3、一般式(I)において、mとnの和が4〜12であることを特徴とする発明1又は2記載の重合性液晶組成物。発明4、液晶相から等方性液体相への転移温度が80℃以下であることを特徴とする発明1から3のいずれか一つの発明に記載の重合性液晶組成物。
【０００７】
本発明の重合性液晶組成物中に含有される一般式(I)で表される重合性液晶化合物の一部とこれを含有する組成物は、米国特許第6042745号公報に記載されている。しかしながら、該公報は、重合性液晶化合物としてあり得る部分化学構造の組み合わせを羅列しているに過ぎず、注入工程への適用における安息香酸フェニルエステルの有用性についての記載はない。また、栗原等も一般式(I)で表される重合性液晶化合物を用いた高分子フィルムについて、第23回液晶討論会予稿集(東京)30〜31頁に報告している。しかしながら、液晶下限温度の重要性の認識もなく、40℃以下が好ましいとの記載もない。
【０００８】
これらに対し、本発明は一般式(I)の化合物を組成成分の一つとして使用することにより、液晶下限温度を40℃以下に抑制せしめ、かつ液晶セル等への注入工程への適用性に優れた重合性液晶組成物、つまり注入工程において多大な時間がかからず、活性エネルギー線の照射により均一性や機械的特性の両立できることを見出したものである。
【０００９】
【発明の実施の形態】
以下、本発明の実施形態の例を説明する。一般式(I)において、活性エネルギー線に対する硬化性を良好にするためにはX¹、X²は水素原子であることが好ましい。m、nは各々3〜8であることが好ましく、3〜6であることがさらに好ましい。mとnの和を4〜12にすると、ネマチック相を発現しやすい傾向にあるため好ましい。スメクチック相が求められる場合、mとnの和を13以上に設定すると良いが、あまりmとnの和が大きくなると、活性エネルギー線の照射により得られる高分子の耐熱性や機械的特性が悪化する場合がある。液晶温度を低減する目的からは、Y¹、Y²は各々独立的に炭素原子数1〜5のアルキル基、アルコキシ基、フッ素原子、塩素原子が好ましく、炭素原子数1〜2のアルキル基、アルコキシ基、フッ素原子がさらに好ましく、炭素原子数1〜2のアルキル基、フッ素原子が特に好ましい。pとqは各々0〜2の整数が好ましく、0もしくは1がさらに好ましい。
【００１０】
一般式(I)で表される化合物の具体的な例を、式(1)〜(19)に示す。しかしながら、本発明の重合性液晶組成物で使用することのできる化合物は、これらに限定されるものではない。
【化３】

【化４】

(式中、m、nは各々独立的に2〜10の整数を表す)
【００１１】
本発明の重合性液晶組成物には、一般式(I)で表される化合物を90質量%以上、さらに好ましくは95質量%以上、特に好ましくは、97質量%以上含有するのが好ましい。一般式(I)で表される化合物の含有量が多いほど、注入工程における効率と活性エネルギー線の照射により得られる高分子の耐熱性や機械的特性の両立を高い次元で実現することができる。
本発明の重合性液晶組成物には、一般式(I)で表される化合物以外の重合性液晶化合物を含有させても良いが、本発明の目的から逸脱しないように、その添加量を制限するのが好ましく、その含有量は10質量%以下が好ましく、5質量%以下がさらに好ましく、3質量%以下が特に好ましい。特に、液晶骨格として3つ以上の環を有する重合性液晶化合物は、一般的に透明点を上昇させる効果があり、適切な使用量においては有効であるが、注入時間の増大を招きやすい性質があるので、その添加量は7質量%以下が好ましく、4質量%以下がさらに好ましく、3質量%以下が特に好ましい。
【００１２】
本発明の重合性液晶組成物が示す液晶相は、この技術分野で液晶相と呼ばれるものであれば、特に制限はない。本発明の重合性液晶組成物を一軸に配向させる必要がある場合には、ネマチック相、スメクチックA相が好ましく、螺旋状に配向させる必要がある場合にはキラルネマチック相、キラルスメクチックC相が好ましく、強誘電性を発現させる必要がある場合には、キラルスメクチックC相が好ましい。これらの中でも、ネマチック相、キラルネマチック相は用途が広く有用であり、ネマチック相は特に有用である。
本発明の重合性液晶組成物の液晶下限温度は40℃以下であることが望ましい。液晶下限温度が低いほど、低い温度において配向させることや、低い温度において紫外線等の活性エネルギー線の照射により配向固定を行うことができ、良好な均一性の確保が容易になる。このことから、液晶下限温度は30℃以下がさらに好ましく、25℃以下が特に好ましい。
【００１３】
本発明の重合性液晶組成物には、一般式(I)で表される化合物を少なくとも2種含有させることが好ましい。これによって、得られる液晶相の熱的な安定性を増すことができる。つまり、より広い温度範囲において液晶相を確保しやすくなる。特に、式(1)の化合物同士の組み合わせ、式(1)と式(2)〜(5)から少なくとも一つ選ばれる化合物との組み合わせ、式(1)と式(13)〜(14)から少なくとも一つ選ばれる化合物との組み合わせ、式(1)と式(18)〜(19)から少なくとも一つ選ばれる化合物との組み合わせはネマチック相を得るためには好ましい。式(1)の化合物同士の組み合わせ、式(1)と式(6)〜(12)から少なくとも一つ選ばれる化合物の組み合わせ、式(1)と式(15)〜(17)から選ばれる化合物との組み合わせはスメクチック相を得るためには好ましい。式(1)で表される化合物において、mとnの和が異なる化合物同士を組み合わせると、スメクチック相及びネマチック相の双方を発現する傾向があるため、特に好ましい。
【００１４】
本発明の重合性液晶組成物の透明点は、80℃以下に調整するのが好ましく、60℃以下がさらに好ましく、55℃以下が特に好ましく、50℃以下が非常に好ましい。このようにすると、注入工程等において本発明の重合性液晶組成物を等方性液体相にする必要がある場合でも、80℃以上のような高い温度にする必要が無く、結果として望ましくない熱重合の誘起を避けることができる。
本発明の重合性液晶組成物には、その重合反応性を向上させることを目的として、光重合開始剤を添加することができる。光重合開始剤としては、ベンゾインエーテル類、ベンゾフェノン類、アセトフェノン類、ベンジルケタール類、アシルフォスフィンオキサイド等が挙げられる。その添加量は、液晶組成物に対して0.01〜5質量%が好ましく、0.02〜1質量%がさらに好ましく、0.03〜1質量%の範囲が特に好ましい。また、本発明の重合性液晶組成物には、その保存安定性を向上させるために、安定剤を添加することもできる。使用できる安定剤としては、例えば、ヒドロキノン、ヒドロキノンモノアルキルエーテル類、第三ブチルカテコール類、ピロガロール類、チオフェノール類、ニトロ化合物類、β-ナフチルアミン類、β-ナフトール類、ニトロソ化合物等が挙げられる。安定剤を使用する場合の添加量は、液晶組成物に対して0.005〜1質量%の範囲が好ましく、0.02〜0.5質量%がさらに好ましく、0.03〜0.1質量%が特に好ましい。
【００１５】
本発明の重合性液晶組成物には、液晶骨格の螺旋構造を内部に有する高分子を得ることを目的として、キラル化合物を添加することもできる。そのような目的で使用するキラル化合物は、それ自体が液晶性を示す必要は無く、また重合性官能基を有していても、有していなくても良い。また、その螺旋の向きは、重合体の使用用途によって適宜選択することができる。そのようなキラル化合物としては、例えば、キラル基としてコレステリル基を有するペラルゴン酸コレステロール、ステアリン酸コレステロール、キラル基として2-メチルブチル基を有するビーディーエイチ社(BDH社;イギリス国)製の「CB-15」、「C-15」、メルク社(ドイツ国)製の「S-1082」、チッソ社製の「CM-19」、「CM-20」、「CM」、キラル基として1-メチルヘプチル基を有するメルク社製の「S-811」、チッソ社製の「CM-21」、「CM-22」などを挙げることができる。キラル化合物を添加する場合の好ましい添加量は、液晶組成物の用途によるが、重合して得られる重合体の厚み(d)を重合体中での螺旋ピッチ(P)で除した値(d/P)が0.1〜100の範囲となる量が好ましく、0.1〜20の範囲となる量がさらに好ましい。
また、本発明の重合性液晶組成物を偏光フィルムや配向膜の原料、又は印刷インキ及び塗料、保護膜等の用途に利用する場合には、その目的に応じて金属、金属錯体、染料、顔料、色素、蛍光材料、燐光材料、界面活性剤、レベリング剤、チキソ剤、ゲル化剤、多糖、紫外線吸収剤、赤外線吸収剤、抗酸化剤、イオン交換樹脂、酸化チタン等の金属酸化物等を添加することもできる。
【００１６】
【実施例】
以下、実施例を挙げて本発明を更に詳述するが、本発明はこれらの実施例に限定されるものではない。
【００１７】
(実施例1)
化合物(20)の化合物50質量部
【化５】

(本化合物は、25℃で結晶相を示す。加熱すると59〜63℃で等方性液体相に相転移する。等方性液体相から冷却すると、51℃でネマチック相に相転移する。さらに冷却すると50℃でスメクチックA相に転移する)及び化合物(21)の化合物50質量部
【化６】

(本化合物は、25℃で結晶相を示す。加熱すると50〜51℃で等方性液体相に相転移する。等方性液体相から冷却すると34℃でネマチック相に相転移する)から成る重合性液晶組成物(A)を調製した。重合性液晶組成物(A)は、室温(25℃)でスメクチックAを呈した。スメクチックA相-ネマチック相転移温度は36℃であった。ネマチック-等方性液体相転移温度は43℃であった。
【００１８】
この重合性液晶組成物(A)に、光重合開始剤としてルシリンTPO(BASF社製)を0.1質量%添加し、重合性液晶組成物(B)を調製した。重合性液晶組成物(B)は、室温(25℃)でスメクチックＡを呈した。スメクチックA相-ネマチック相転移温度は36℃であった。ネマチック-等方性液体相転移温度は43℃であった。これを50μmのセルギャップを有するアンチパラレル配向処理をした硝子製液晶セルに注入した。この注入は50℃に加熱した状態で行ったが、注入は迅速に完了した。注入完了後、25℃において中心波長360nmで2mW/cm²の強度の紫外線を照射したところ、約2分で硬化した。このようにして作製した高分子を偏光顕微鏡で観察したところ、硬化前のスメクチックA相の配向状態がそのまま固定化された高分子が得られたことが確認できた。また、注入工程において熱重合しておらず、配向状態は非常に均一であることが確認できた。さらに、硝子製液晶セルを分解して、得られた高分子単体を取り出し、耐熱性を検討したところ、150℃においても配向は乱れず、問題の無いことを確認できた。また、得られた高分子はゲル状ではなく機械的特性も優れていた。
【００１９】
(実施例2)
実施例1で調製した重合性液晶組成物(B)を、50μmのセルギャップを有するアンチパラレル配向処理をした硝子製液晶セルに注入した。この注入は38℃に加熱した状態で行ったが、迅速に完了した。注入完了後、38℃において中心波長360nmで2mW/cm²の強度の紫外線を照射したところ、約2分で硬化した。このようにして作製した高分子を偏光顕微鏡で観察したところ、硬化前のネマチック相の配向状態がそのまま固定化された高分子が得られたことが確認できた。また、注入工程において熱重合しておらず、配向状態は非常に均一であることが確認できた。さらに、硝子製液晶セルを分解して、得られた高分子単体を取り出し、耐熱性を検討したところ、150℃においても配向は乱れず、耐熱性が優れていることを確認できた。また、得られた高分子はゲル状ではなく機械的特性も優れていた。
【００２０】
【発明の効果】
本発明の重合性液晶組成物は、液晶セル等への注入工程が迅速に完了し、生産性に優れる。また、活性エネルギー線の照射により均一性、機械的特性に優れた高分子を与える。この点から本発明の重合性液晶組成物は、位相差フィルムや光学的ローパスフィルター等の製造を容易にするものであり、極めて有用である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a polymerizable liquid crystal composition, and more particularly to a polymerizable liquid crystal composition suitable for polymerization using energy rays such as ultraviolet rays.
[0002]
[Prior art]
After aligning a liquid crystal compound having a polymerizable functional group (hereinafter, polymerizable liquid crystal compound) or a polymerizable liquid crystal composition containing at least one such compound in a liquid crystal state, activity such as ultraviolet rays is performed in that state. When irradiated with energy rays, a polymer in which the alignment state structure of liquid crystal molecules is fixed can be produced. The polymer thus obtained has anisotropy of physical properties such as refractive index, dielectric constant, magnetic susceptibility, elastic modulus, and thermal expansion coefficient. It can be applied as a coating agent such as a plate, a polarizing prism, a waveguide, a piezoelectric element, a nonlinear optical element, various optical filters, a pigment using selective reflection of a cholesteric liquid crystal phase, and an optical fiber.
As described above, when using the polymerizable liquid crystal composition, it is necessary to align the polymerizable liquid crystal composition while maintaining the temperature at which the polymerizable liquid crystal composition exhibits liquid crystallinity. If the minimum liquid crystal temperature of the polymerizable liquid crystal composition is higher than 40 ° C., there is a risk that undesirable thermal polymerization is induced in this alignment step, and the uniformity of the alignment of the polymer to be produced is impaired.
[0003]
Further, when the polymerizable liquid crystal composition is used, the polymerizable liquid crystal composition may be aligned by being injected into a liquid crystal cell having a gap of several to several tens of μm. There was a problem that it took a lot of time to inject the resin and the productivity deteriorated. As a means for reducing the time required for injection, it is effective to heat the polymerizable liquid crystal composition to a temperature higher than the transition temperature from the liquid crystal phase to the isotropic liquid phase (hereinafter referred to as the clearing point). When the temperature is higher than 80 ° C., undesirable thermal polymerization is induced, which may cause problems in the uniformity and quality of the resulting polymer. As a means for reducing the time required for injection, a liquid crystal compound having no polymerizable functional group and having a low viscosity or a polymerizable liquid crystal compound having only one polymerizable functional group and having a low viscosity is used. Although it is effective to add, the heat resistance and mechanical properties of the polymer obtained by irradiation with active energy rays such as ultraviolet rays tend to deteriorate, that is, the efficiency in the injection process and the heat resistance of the obtained polymer It was difficult to achieve both mechanical properties.
[0004]
[Problems to be solved by the invention]
The problem to be solved by the present invention is a polymerizable liquid crystal composition having a liquid crystal lower limit temperature of 40 ° C. or less and excellent in applicability to an injection process into a liquid crystal cell or the like, that is, a long time is required in the injection process. Therefore, an object of the present invention is to provide a polymerizable liquid crystal composition that gives a polymer having excellent uniformity and mechanical properties by irradiation with active energy rays.
[0005]
[Means for Solving the Problems]
The present invention focuses on the chemical structure of a polymerizable liquid crystal compound in order to solve the above problems, and as a result, as a result, the liquid crystal skeleton is a bicyclic benzoic acid phenyl ester having two (meth) acryloyloxy groups. The inventors found that a polymerizable liquid crystal compound is useful, and found the following polymerizable liquid crystal composition.
[0006]
Invention 1, General Formula (I)
[Chemical 2]

(Wherein X ¹ and X ² each independently represent a hydrogen atom or a methyl group, m and n each independently represents an integer of 2 to 10, Y ¹ and Y ² are each independently a carbon atom, containing 1-5 alkyl group, an alkoxy group, a halogen atom, p, among the compounds represented by q represents an integer of each independently 0-4), at least two of the sum of m and n is different from A polymerizable liquid crystal composition comprising: a compound having a minimum liquid crystal temperature of 40 ° C. or lower. Invention 2: A polymerizable liquid crystal composition according to Invention 1, comprising at least 90% by mass or more of the compound represented by the general formula (I). Invention 3 The polymerizable liquid crystal composition according to Invention 1 or 2 , wherein the sum of m and n is 4 to 12 in the general formula (I). Invention 4 The polymerizable liquid crystal composition according to any one of Inventions 1 to 3 , wherein the transition temperature from the liquid crystal phase to the isotropic liquid phase is 80 ° C. or lower.
[0007]
A part of the polymerizable liquid crystal compound represented by the general formula (I) contained in the polymerizable liquid crystal composition of the present invention and a composition containing the same are described in US Pat. No. 6,042,745. However, this publication only lists the combinations of partial chemical structures that can be used as polymerizable liquid crystal compounds, and does not describe the usefulness of benzoic acid phenyl ester in application to an injection process. Kurihara et al. Also reported on the 23rd Liquid Crystal Discussion Group Proceedings (Tokyo), pp. 30-31, about polymer films using polymerizable liquid crystal compounds represented by the general formula (I). However, there is no recognition of the importance of the liquid crystal lower limit temperature, and there is no description that 40 ° C. or lower is preferable.
[0008]
On the other hand, the present invention uses the compound of the general formula (I) as one of the composition components to suppress the liquid crystal lower limit temperature to 40 ° C. or less and to be applicable to an injection process into a liquid crystal cell or the like. It has been found that an excellent polymerizable liquid crystal composition, that is, it does not take much time in the injection step, and both uniformity and mechanical properties can be achieved by irradiation with active energy rays.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, examples of embodiments of the present invention will be described. In general formula (I), X ¹ and X ² are preferably hydrogen atoms in order to improve curability to active energy rays. m and n are each preferably 3 to 8, and more preferably 3 to 6. The sum of m and n is preferably 4 to 12 because it tends to develop a nematic phase. When a smectic phase is required, the sum of m and n should be set to 13 or more. However, if the sum of m and n becomes too large, the heat resistance and mechanical properties of the polymer obtained by irradiation with active energy rays deteriorate. There is a case. For the purpose of reducing the liquid crystal temperature, Y ¹ and Y ² are each independently preferably an alkyl group having 1 to 5 carbon atoms, an alkoxy group, a fluorine atom, or a chlorine atom, and an alkyl group having 1 to 2 carbon atoms, An alkoxy group and a fluorine atom are more preferable, and an alkyl group having 1 to 2 carbon atoms and a fluorine atom are particularly preferable. p and q are each preferably an integer of 0 to 2, more preferably 0 or 1.
[0010]
Specific examples of the compound represented by the general formula (I) are shown in the formulas (1) to (19). However, compounds that can be used in the polymerizable liquid crystal composition of the present invention are not limited thereto.
[Chemical 3]

[Formula 4]

(In the formula, m and n each independently represents an integer of 2 to 10)
[0011]
The polymerizable liquid crystal composition of the present invention preferably contains 90% by mass or more, more preferably 95% by mass or more, and particularly preferably 97% by mass or more of the compound represented by the general formula (I). The higher the content of the compound represented by the general formula (I), the higher the compatibility between the efficiency in the injection process and the heat resistance and mechanical properties of the polymer obtained by irradiation with active energy rays can be realized. .
The polymerizable liquid crystal composition of the present invention may contain a polymerizable liquid crystal compound other than the compound represented by the general formula (I), but its addition amount is limited so as not to depart from the purpose of the present invention. The content is preferably 10% by mass or less, more preferably 5% by mass or less, and particularly preferably 3% by mass or less. In particular, a polymerizable liquid crystal compound having three or more rings as a liquid crystal skeleton generally has an effect of increasing a clearing point, and is effective in an appropriate amount of use, but has a property that easily causes an increase in injection time. Therefore, the amount added is preferably 7% by mass or less, more preferably 4% by mass or less, and particularly preferably 3% by mass or less.
[0012]
If the liquid crystal phase which the polymeric liquid crystal composition of this invention shows is called a liquid crystal phase in this technical field, there will be no restriction | limiting in particular. When it is necessary to align the polymerizable liquid crystal composition of the present invention uniaxially, a nematic phase and a smectic A phase are preferable, and when it is necessary to align a helical shape, a chiral nematic phase and a chiral smectic C phase are preferable. When it is necessary to develop ferroelectricity, a chiral smectic C phase is preferable. Among these, the nematic phase and the chiral nematic phase are widely useful, and the nematic phase is particularly useful.
The minimum liquid crystal temperature of the polymerizable liquid crystal composition of the present invention is desirably 40 ° C. or lower. The lower the liquid crystal lower limit temperature, the lower the temperature, the lower the temperature, and the lower the temperature, the more the alignment can be fixed by irradiation with active energy rays such as ultraviolet rays. For this reason, the lower limit temperature of the liquid crystal is more preferably 30 ° C. or less, and particularly preferably 25 ° C. or less.
[0013]
The polymerizable liquid crystal composition of the present invention preferably contains at least two compounds represented by the general formula (I). Thereby, the thermal stability of the obtained liquid crystal phase can be increased. That is, it becomes easy to secure a liquid crystal phase in a wider temperature range. In particular, a combination of compounds of formula (1), a combination of formula (1) and at least one compound selected from formulas (2) to (5), from formula (1) and formulas (13) to (14) A combination with at least one compound, and a combination with at least one compound selected from the formulas (1) and (18) to (19) are preferred in order to obtain a nematic phase. Combination of compounds of formula (1), combination of compounds selected from formula (1) and formulas (6) to (12), compound selected from formula (1) and formulas (15) to (17) Is preferable for obtaining a smectic phase. In the compound represented by the formula (1), it is particularly preferable to combine compounds having different sums of m and n because both tend to exhibit both a smectic phase and a nematic phase.
[0014]
The clearing point of the polymerizable liquid crystal composition of the present invention is preferably adjusted to 80 ° C. or less, more preferably 60 ° C. or less, particularly preferably 55 ° C. or less, and very preferably 50 ° C. or less. In this way, even when it is necessary to make the polymerizable liquid crystal composition of the present invention into an isotropic liquid phase in the injection step or the like, it is not necessary to set the temperature as high as 80 ° C. or higher, resulting in undesirable heat. Induction of polymerization can be avoided.
A photopolymerization initiator can be added to the polymerizable liquid crystal composition of the present invention for the purpose of improving the polymerization reactivity. Examples of the photopolymerization initiator include benzoin ethers, benzophenones, acetophenones, benzyl ketals, and acylphosphine oxides. The addition amount is preferably 0.01 to 5% by mass, more preferably 0.02 to 1% by mass, and particularly preferably 0.03 to 1% by mass with respect to the liquid crystal composition. In addition, a stabilizer can be added to the polymerizable liquid crystal composition of the present invention in order to improve its storage stability. Examples of the stabilizer that can be used include hydroquinone, hydroquinone monoalkyl ethers, tert-butylcatechols, pyrogallols, thiophenols, nitro compounds, β-naphthylamines, β-naphthols, and nitroso compounds. . When the stabilizer is used, the addition amount is preferably 0.005 to 1% by mass, more preferably 0.02 to 0.5% by mass, and particularly preferably 0.03 to 0.1% by mass with respect to the liquid crystal composition.
[0015]
A chiral compound can be added to the polymerizable liquid crystal composition of the present invention for the purpose of obtaining a polymer having a helical structure of a liquid crystal skeleton inside. The chiral compound used for such a purpose does not need to exhibit liquid crystal properties per se, and may or may not have a polymerizable functional group. Moreover, the direction of the spiral can be appropriately selected depending on the intended use of the polymer. As such a chiral compound, for example, “CB-” manufactured by BDH (BDH; UK) having cholesteryl group cholesteryl group as a chiral group, cholesterol stearate, and 2-methylbutyl group as a chiral group. `` 15 '', `` C-15 '', Merck (Germany) `` S-1082 '', Chisso `` CM-19 '', `` CM-20 '', `` CM '', 1-methylheptyl as chiral group Examples thereof include “S-811” manufactured by Merck Co., Ltd., and “CM-21” and “CM-22” manufactured by Chisso. The preferred addition amount when adding a chiral compound depends on the use of the liquid crystal composition, but the value obtained by dividing the thickness (d) of the polymer obtained by polymerization by the helical pitch (P) in the polymer (d / P) is preferably in an amount ranging from 0.1 to 100, more preferably in an amount ranging from 0.1 to 20.
In addition, when the polymerizable liquid crystal composition of the present invention is used for a raw material of a polarizing film or an alignment film, a printing ink, a paint, a protective film or the like, a metal, a metal complex, a dye, or a pigment depending on the purpose. Dyes, fluorescent materials, phosphorescent materials, surfactants, leveling agents, thixotropic agents, gelling agents, polysaccharides, UV absorbers, infrared absorbers, antioxidants, ion exchange resins, metal oxides such as titanium oxide, etc. It can also be added.
[0016]
【Example】
EXAMPLES Hereinafter, although an Example is given and this invention is further explained in full detail, this invention is not limited to these Examples.
[0017]
(Example 1)
50 parts by mass of compound (20)

(This compound exhibits a crystalline phase at 25 ° C. When heated, it transitions to an isotropic liquid phase at 59-63 ° C. When cooled from an isotropic liquid phase, it transitions to a nematic phase at 51 ° C.) When cooled, it transitions to a smectic A phase at 50 ° C.) and 50 parts by mass of compound (21)

(This compound exhibits a crystalline phase at 25 ° C. When heated, it transforms into an isotropic liquid phase at 50-51 ° C. When cooled from an isotropic liquid phase, it transforms into a nematic phase at 34 ° C) A polymerizable liquid crystal composition (A) was prepared. The polymerizable liquid crystal composition (A) exhibited smectic A at room temperature (25 ° C.). The smectic A-nematic phase transition temperature was 36 ° C. The nematic-isotropic liquid phase transition temperature was 43 ° C.
[0018]
To this polymerizable liquid crystal composition (A), 0.1% by mass of lucillin TPO (manufactured by BASF) was added as a photopolymerization initiator to prepare a polymerizable liquid crystal composition (B). The polymerizable liquid crystal composition (B) exhibited smectic A at room temperature (25 ° C.). The smectic A-nematic phase transition temperature was 36 ° C. The nematic-isotropic liquid phase transition temperature was 43 ° C. This was injected into a liquid crystal cell made of glass having an anti-parallel alignment treatment having a cell gap of 50 μm. This injection was performed while heating to 50 ° C., but the injection was completed quickly. After completion of the injection, it was irradiated with ultraviolet rays having an intensity of ² mW / cm ² at a central wavelength of 360 nm at 25 ° C., and cured in about 2 minutes. Observation of the polymer thus prepared with a polarizing microscope confirmed that a polymer in which the orientation state of the smectic A phase before curing was fixed as it was was obtained. Moreover, it was not heat-polymerized in the injection | pouring process, and it has confirmed that the orientation state was very uniform. Furthermore, when the glass liquid crystal cell was disassembled, and the obtained polymer alone was taken out and examined for heat resistance, the orientation was not disturbed even at 150 ° C., and it was confirmed that there was no problem. Further, the obtained polymer was not gel-like and excellent in mechanical properties.
[0019]
(Example 2)
The polymerizable liquid crystal composition (B) prepared in Example 1 was injected into a glass liquid crystal cell having an anti-parallel alignment treatment having a cell gap of 50 μm. This injection was performed while heated to 38 ° C., but was completed quickly. After completion of the injection, it was irradiated with ultraviolet rays having a central wavelength of 360 nm and an intensity of ² mW / cm ² at 38 ° C., and cured in about 2 minutes. When the polymer thus prepared was observed with a polarizing microscope, it was confirmed that a polymer in which the alignment state of the nematic phase before curing was fixed as it was was obtained. Moreover, it was not heat-polymerized in the injection | pouring process, and it has confirmed that the orientation state was very uniform. Furthermore, when the glass liquid crystal cell was disassembled and the obtained polymer alone was taken out and the heat resistance was examined, the orientation was not disturbed even at 150 ° C., and it was confirmed that the heat resistance was excellent. Further, the obtained polymer was not gel-like and excellent in mechanical properties.
[0020]
【The invention's effect】
The polymerizable liquid crystal composition of the present invention is excellent in productivity because the injection process into a liquid crystal cell or the like is completed quickly. In addition, irradiation with active energy rays gives a polymer with excellent uniformity and mechanical properties. From this point, the polymerizable liquid crystal composition of the present invention facilitates the production of a retardation film, an optical low-pass filter and the like, and is extremely useful.

Claims (4)

Formula (I)

(Wherein X ¹ and X ² each independently represent a hydrogen atom or a methyl group, m and n each independently represents an integer of 2 to 10, Y ¹ and Y ² are each independently a carbon atom, containing 1-5 alkyl group, an alkoxy group, a halogen atom, p, among the compounds represented by q represents an integer of each independently 0-4), at least two of the sum of m and n is different from A polymerizable liquid crystal composition comprising: a compound having a minimum liquid crystal temperature of 40 ° C. or lower.  2. The polymerizable liquid crystal composition according to claim 1, comprising at least 90% by mass or more of the compound represented by the general formula (I). 3. The polymerizable liquid crystal composition according to claim 1, wherein the sum of m and n in the general formula (I) is 4 to 12. The polymerizable liquid crystal composition according to any one of claims of claims 1 to 3, wherein the transition temperature to an isotropic liquid phase from the liquid crystal phase is 80 ° C. or less.