JP2006276649A - Composition for polymer-dispersed liquid crystal display element and polymer-dispersed liquid crystal display element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a composition for a polymer-dispersed liquid crystal display element and the polymer-dispersed liquid crystal element, which are superior in low-driving voltage characteristics in a low-temperature area and have a high voltage holding ratio and can be driven by an active element. <P>SOLUTION: The composition for a polymer-dispersed liquid crystal display element contains a compound selected from groups given by a general formula (I-a) and a general formula (I-b) and contains a compound given by a general formula (I-c) and contains a compound given by a general formula (II-b) and contains a polymerization initiator, and the polymer-dispersed liquid crystal element uses this composition. The liquid crystal display element has a wide operation temperature range and is superior in scattering characteristic and has less changes with time in these properties and is superior in thermal resistance and light resistance and is very practical for a display device utilizing light scattering. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a composition useful for a polymer-dispersed liquid crystal display element that can be driven by an active element, and a polymer-dispersed liquid crystal display element using the composition.

Since the polymer dispersion type liquid crystal display element does not require a polarizing plate, it has a merit that a bright display can be realized compared with a liquid crystal display element of TN, STN, IPS or VA mode using a conventional polarizing plate. Since this structure is also simple, it is applied to optical shutter applications such as light control glass and non-patent document 1 segment display applications such as watches. In addition, in order to realize high-definition display, as seen in Non-Patent Document 2 and Non-Patent Document 3, application to a projector application, a reflective display application, or the like in combination with an active drive element is also being studied.

  In order to operate a polymer-dispersed liquid crystal display element with active driving, it is necessary to be able to drive with a low voltage and to have a high voltage holding ratio. Furthermore, these characteristics are in a wide temperature range for practical display elements. Must be achieved. As a low-voltage driving technique, Patent Document 1 discloses a technique in which a transparent solid substance is formed in a three-dimensional network structure in a liquid crystal continuous phase, and Patent Document 2, Patent Document 3, and Patent Document 4 disclose. Discloses a technique for achieving a low driving voltage by using a side chain type radically polymerizable compound. However, in these inventions, a cyano compound is used as a liquid crystal material to achieve a high voltage holding ratio. Is difficult and cannot be applied to active drive elements.

  On the other hand, as an example of a liquid crystal composition capable of being driven at a low voltage and having a high voltage holding ratio, Patent Document 5 discloses an example achieved using a fluorine-based or chlorine-based liquid crystal composition. However, in the composition described in the cited document, a monofunctional acrylate having a molecular weight of 250 or less is used for the prepolymer (used in place of the compound represented by the general formula (II-b) in the present invention). Therefore, there has been a problem that the monofunctional acrylate is volatilized in a vacuum state during the manufacturing process of the liquid crystal display element and the ratio of the composition is changed.

  Patent Document 6 discloses an example in which a high voltage holding ratio and a low driving voltage are achieved using a fluorine-based liquid crystal composition. However, since the liquid crystal composition described in the cited document has a crystallization temperature of about −10 ° C., it is difficult to operate at −20 ° C., and the operation lower limit temperature at which a practical low voltage is possible is about 0 ° C.

  As described above, in the polymer dispersion type liquid crystal display element, it is difficult to reduce the voltage in the low temperature region, and particularly in the active driving application, the low voltage driving in the low temperature region of 0 ° C. or less has not been achieved. There has been a demand for low-voltage operation in a lower temperature range. In addition, since the temperature dependency of the driving voltage in the low temperature region is large, a composition capable of reducing the temperature dependency and an element having a small temperature dependency have been demanded.

JP-A-1-198725 (Claim 1) JP-A-6-32761 (pages 9 to 12) JP 11-29527 A (pages 19 to 22) JP 2002-293828 A (pages 17 to 18) JP-A-5-339573 (pages 5 to 8) JP-A-9-255554 (pages 16 to 24) Display International Workshop (IDW) '97 Digest, 1997 (page 156) 1991 Society for Information Display (SID) International Symposium Digest of Technical Paper (page 251) 2001 Society for Information Display (SID) International Symposium Digest of Technical Paper (page 264)

  An object of the present invention is to provide a composition for a polymer-dispersed liquid crystal display element that is excellent in low drive voltage characteristics in a low temperature region without using a highly volatile compound, has a high voltage holding ratio, and can be driven by an active element, and The object is to provide a polymer-dispersed liquid crystal display element. In particular, in a mobile application, a composition for a polymer-dispersed liquid crystal display element, which is excellent in low driving voltage characteristics in a low temperature range and can be driven by an active element having a small temperature dependency, and a polymer-dispersed liquid crystal display element Is to provide.

In order to solve the above-mentioned problems, the present invention has studied the combinations of various liquid crystal compositions and radical polymerizable compounds, and as a result, has come to solve the problems.
That is, general formula (Ia) and general formula (Ib)

(In the formula, R ¹ and R ² each independently represents an alkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, and one or more present in the alkyl group or alkenyl group or Two or more CH ₂ groups may be substituted with oxygen atoms, assuming that the oxygen atoms are not directly bonded to each other,
A ¹ , A ² and A ³ each independently represents a 1,4-phenylene group or a 1,4-cyclohexylene group, and the 1,4-phenylene group is unsubstituted or has one substituent. Or two or more fluorine atoms, chlorine atoms, methyl groups or trifluoromethyl groups or trifluoromethoxy groups,
X ¹ and X ⁷ each independently represent a fluorine atom, a chlorine atom, an isocyanate group, a trifluoromethyl group, a trifluoromethoxy group or a difluoromethoxy group,
X ² to X ⁵ and X ⁸ to X ¹⁰ each independently represent a hydrogen atom, a fluorine atom, a chlorine atom, a trifluoromethyl group or a trifluoromethoxy group, and X ¹¹ and X ¹² each independently represent a hydrogen atom. Represents an atom, a fluorine atom, a chlorine atom, a trifluoromethyl group or a trifluoromethoxy group, and when A2 represents a 1,4-cyclohexylene group, X ¹¹ and X ¹² represent a hydrogen atom,
Z ¹ and Z ³ each independently represent a single bond, —CH ₂ —CH ₂ — or —COO—,
Z ² and Z ⁴ each independently represent a single bond, —CH ₂ —CH ₂ — or —CF ₂ O—,
n ¹ and n ² represent 0 or 1. )
Containing at least one compound from the group of compounds represented by formula (Ic)

(Wherein R ²¹ represents an alkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, and one or more CH ₂ groups present in the alkyl group or alkenyl group are , As oxygen atoms are not directly bonded to each other, may be substituted with oxygen atoms,
A ²¹ represents a 1,4-phenylene group or a 1,4-cyclohexylene group, and the 1,4-phenylene group is unsubstituted or substituted with one or more fluorine atoms, chlorine atoms, Can have a methyl group or a trifluoromethyl group or a trifluoromethoxy group,
Z ²¹ represents a single bond or —CH ₂ —CH ₂ —, —COO—, —CF ₂ O—,
X ⁵¹ represents an alkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms (one or two or more CH ₂ groups present in the alkyl group or alkenyl group have an oxygen atom And may be substituted with an oxygen atom as a group not directly bonded to), a fluorine atom, a chlorine atom, an isocyanate group, a trifluoromethyl group, a trifluoromethoxy group, a difluoromethoxy group, or a general formula (Id),

（式中、A²²は1,4-フェニレン基又は1,4-シクロヘキシレン基を表し、該1,4-フェニレン基は非置換であるか又は置換基として１個又は２個以上のフッ素原子、塩素原子、メチル基又はトリフルオロメチル基又はトリフルオロメトキシ基を有することができ、
X⁶⁰は、炭素原子数1から10のアルキル基又は炭素原子数2から10のアルケニル基（該アルキル基又はアルケニル基中に存在する１個又は２個以上のCH₂基は、酸素原子が相互に直接結合しないものとして、酸素原子で置換されていてもよい。）、フッ素原子、塩素原子、イソシアネート基、トリフルオロメチル基、トリフルオロメトキシ基、又はジフルオロメトキシ基基を表す。）
X⁵²からX⁵⁷はそれぞれ独立して、水素原子、フッ素原子、塩素原子、トリフルオロメチル基、トリフルオロメトキシ基、メチル基、メトキシ基又はエチル基を表し、
n¹⁰は0又は１を表す。）
で表される化合物群から選ばれる化合物を少なくとも一種類含有し、一般式(II-b)

(In the formula, A ²² represents a 1,4-phenylene group or a 1,4-cyclohexylene group, and the 1,4-phenylene group is unsubstituted or has one or more fluorine atoms as a substituent. A chlorine atom, a methyl group or a trifluoromethyl group or a trifluoromethoxy group,
X ⁶⁰ represents an alkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms (one or two or more CH ₂ groups present in the alkyl group or alkenyl group have an oxygen atom And a fluorine atom, a chlorine atom, an isocyanate group, a trifluoromethyl group, a trifluoromethoxy group, or a difluoromethoxy group. )
X ⁵² to X ⁵⁷ each independently represent a hydrogen atom, a fluorine atom, a chlorine atom, a trifluoromethyl group, a trifluoromethoxy group, a methyl group, a methoxy group or an ethyl group,
n ¹⁰ represents 0 or 1. )
Containing at least one compound selected from the group of compounds represented by formula (II-b)

(In the formula, B ⁵ , B ⁶ and B ⁷ each independently represents a single bond or an alkylene group having 1 to 19 carbon atoms, and the alkylene group is unsubstituted or has one or two substituents. It may have the above fluorine atom, methyl group, and ethyl group, and one or two or more CH ₂ groups present in the alkylene group are oxygen atoms on the assumption that oxygen atoms are not directly bonded to each other. , -CO-, -COO-, -OCO-, 1,4-phenylene group, pyridine-2,5-diyl group, pyrimidine-2,5-diyl group, 1,3-dioxane-2,5-diyl group 1,4-cyclohexylene group, bicyclo [2.2.2] octane-1,4-diyl group or 3,3′-spirobicyclobutylene may be substituted, and the 1,4-phenylene group is unsubstituted Or one or more fluorine atom, chlorine atom, methyl group, trifluoromethyl group or trifluoromethyl as a substituent. Can have a carboxy group, at least one or more CH ₂ groups in the alkylene group is general formula (II-a)

（式中、B¹は、炭素数2から30のアルキル基を表し、該アルキル基は非置換であるか又は置換基として１個又は２個以上のフッ素原子を有していても良く、該アルキル基中に存在する１個又は２個以上のCH₂基は、酸素原子が相互に直接結合しないものとして酸素原子、−CO−、−COO−、−OCO−、1,4-フェニレン基、ピリジン-2,5-ジイル基、ピリミジン-2,5-ジイル基、1,3-ジオキサン-2,5-ジイル基、1,4-シクロヘキシレン基、ビシクロ[2.2.2]オクタン-1,4-ジイル基又は3,3’-スピロビシクロブチレンで置換されていても良く、
B²は、水素原子又は炭素数1から30のアルキル基を表し、該アルキル基は非置換であるか又は置換基として１個又は２個以上のフッ素原子を有していても良く、該アルキル基中に存在する１個又は２個以上のCH₂基は、酸素原子が相互に直接結合しないものとして酸素原子、−CO−、−COO−、−OCO−、1,4-フェニレン基、ピリジン-2,5-ジイル基、ピリミジン-2,5-ジイル基、1,3-ジオキサン-2,5-ジイル基、1,4-シクロヘキシレン基、ビシクロ[2.2.2]オクタン-1,4-ジイル基又は3,3’-スピロビシクロブチレンで置換されていても良い。）

(Wherein B ¹ represents an alkyl group having 2 to 30 carbon atoms, and the alkyl group may be unsubstituted or may have one or more fluorine atoms as a substituent; One or more CH ₂ groups present in the alkyl group are oxygen atoms, —CO—, —COO—, —OCO—, 1,4-phenylene groups, as oxygen atoms are not directly bonded to each other, Pyridine-2,5-diyl group, pyrimidine-2,5-diyl group, 1,3-dioxane-2,5-diyl group, 1,4-cyclohexylene group, bicyclo [2.2.2] octane-1,4 Optionally substituted with a -diyl group or 3,3'-spirobicyclobutylene,
B ² represents a hydrogen atom or an alkyl group having 1 to 30 carbon atoms, and the alkyl group may be unsubstituted or have one or more fluorine atoms as a substituent. One or more CH ₂ groups present in the group are oxygen atoms, —CO—, —COO—, —OCO—, 1,4-phenylene groups, pyridines, as oxygen atoms are not directly bonded to each other. -2,5-diyl group, pyrimidine-2,5-diyl group, 1,3-dioxane-2,5-diyl group, 1,4-cyclohexylene group, bicyclo [2.2.2] octane-1,4- It may be substituted with a diyl group or 3,3′-spirobicyclobutylene. )

And the total number of carbon atoms of B ⁵ , B ⁶ and B ⁷ is 5 or more,
B ³ and B ⁴ each independently represent a hydrogen atom or a methyl group,
m and n each independently represent 1, 2 or 3. )
And a polymer-dispersed liquid crystal comprising the composition as a constituent member, further comprising a polymerizable compound represented by the formula: An element is provided.

  The polymer-dispersed liquid crystal display element composition and polymer-dispersed liquid crystal display element of the present invention are excellent in low driving voltage characteristics in a low temperature range without using a volatile compound and have a high voltage holding ratio. A liquid crystal display element could be obtained. In addition, the composition and the device have a wide operating temperature range, are excellent in scattering characteristics, have little change over time, and have excellent heat resistance and light resistance, and display using light scattering. Very practical.

An example of the present invention will be described below. In the composition for a polymer dispersed liquid crystal display element of the present invention, the radically polymerizable compound as the second component is polymerized by active energy rays such as heat or ultraviolet rays, and the liquid crystal composition as the first component is associated therewith. It is used for the purpose of causing separation and obtaining a polymer-dispersed liquid crystal display element comprising a transparent polymer substance and a liquid crystal composition.
Japanese Patent Laid-Open No. 6-22220 / 1990 discloses the relationship of the following formula as a description of the driving voltage of the polymer dispersion type liquid crystal display element.

（Ｖthはしきい値電圧を表わし、¹Kii及び²Kiiは弾性定数を表わし、ｉは１、２又は３を表わし、Δεは誘電率異方性を表わし、＜ｒ＞は透明性高分子物質界面の平均空隙間隔を表わし、Ａは液晶組成物に対する透明性高分子物質のアンカリングエネルギーを表わし、ｄは透明性電極を有する基板間の距離を表わす。）

(Vth represents a threshold voltage, ¹ Kii and ² Kii represent elastic constants, i represents 1, 2 or 3, Δε represents dielectric anisotropy, and <r> represents a transparent polymer substance. (Indicates the average gap distance of the interface, A indicates the anchoring energy of the transparent polymer substance with respect to the liquid crystal composition, and d indicates the distance between the substrates having transparent electrodes.)

  According to this, the driving voltage of the polymer-dispersed liquid crystal display element includes the average gap distance at the interface of the transparent polymer material, the distance between the substrates, the elastic constant / dielectric anisotropy of the liquid crystal composition, It is determined by the anchoring energy between transparent polymer materials. Among these parameters that change with temperature are the elastic constant and dielectric anisotropy of the liquid crystal composition and the anchoring energy between the liquid crystal composition and the transparent polymer material. Therefore, the factors that increase the driving voltage in the low temperature range are the elastic constant of the liquid crystal composition and the anchoring energy between the liquid crystal composition and the transparent polymer substance. In particular, when the increase of the anchoring energy at a low temperature increases, the driving voltage exceeds 10 V, and TFT driving at −20 ° C. becomes difficult. Therefore, in order to achieve low voltage driving in a low temperature range, a liquid crystal composition excellent in nematic stability in a wide range of liquid crystal temperatures, particularly in a low temperature range, must be used. A combination with a low anchoring energy between the conductive polymer materials must be found. The anchoring energy greatly depends on the liquid crystal molecular structure and the molecular structure of the transparent polymer substance. For example, in the liquid crystal molecular structure, the ring structure forming the mesogenic group, the number of rings, the position of the substituent in the ring, and the type of the ring structure greatly depend. In the transparent polymer substance, the alkyl side chain length and the distance between the alkyl side chains greatly affect the anchoring energy. Therefore, in order to realize low anchoring energy even at a low temperature, it is necessary to select a liquid crystal compound suitable for the transparent polymer material to be used.

  Therefore, as a result of studying combinations of various liquid crystal compositions and polymerizable compounds, it contains one or more compounds from the group of compounds represented by general formula (Ia) and general formula (Ib). A transparent polymer material obtained by polymerizing a composition containing one or more compounds represented by the general formula (II-b) using a polymerization initiator at a low temperature. It has been found that the anchoring energy between the liquid crystal composition and the transparent polymer material in the region is small.

  The compounds represented by the general formula (I-a), the general formula (I-b), and the general formula (I-c) are compounds that form a liquid crystal composition in the light control layer formed in the polymer dispersion type liquid crystal display device. The liquid crystal composition preferably has not only a wide liquid crystal temperature range but also a high specific resistance value, a high dielectric anisotropy, a high refractive index anisotropy, and a low viscosity. Furthermore, it is also a preferable condition that the liquid crystal composition has excellent heat resistance and light resistance. In particular, in order to drive with an active element, having a high specific resistance value and a high dielectric anisotropy is essential. Also, due to the withstand voltage problem of active devices, the anchoring energy is small between the transparent polymer material and the liquid crystal composition, and the device can be driven at a low voltage of 6 V or less in the device operating temperature range. Is also essential.

From these viewpoints, the compounds represented by the general formula (Ia), general formula (Ib) and general formula (Ic) of the present invention have high compatibility, so that the stability of nematics in a wide liquid crystal temperature range, particularly in a low temperature range. And a compound having a high dielectric constant and a high specific resistance. Combining the compound represented by general formula (Ia) and general formula (Ib) with the compound represented by general formula (Ic) exhibits high refractive index anisotropy and improves the light scattering characteristics of polymer dispersed liquid crystal elements. In addition, the drive voltage is low, the temperature characteristics thereof are good, and the active element can be driven even at a low temperature. For example, in terms of driving voltage, the radically polymerizable compound (X) does not include the compound of the general formula (Ia) and the general formula (Ib), and the liquid crystal composition (L) includes the group of the general formula (Ic) When a polymer-dispersed liquid crystal element is fabricated using the above, the driving voltage is as high as 6V at 25 ° C, 6.8V at 0 ° C, and 15V at -10 ° C. On the other hand, the radically polymerizable compound (X) is polymer-dispersed using the compound of the general formula (Ia) and the group of the general formula (Ib) and the liquid crystal composition (I) of the group of the general formula (Ic). Even when a type liquid crystal element is manufactured, the driving voltage can be compatible with a low driving voltage and good temperature characteristics of 5 V at 25 ° C., 5 V at 0 ° C., and 5.2 V at −10 ° C. That is, when the compound represented by the general formula (Ia), the general formula (Ib), and the general formula (Ic) is formed in the polymer dispersed liquid crystal display element, the transparent polymer substance, the liquid crystal composition, It is shown that the anchoring energy can be reduced between the two, and that the anchoring energy with the polymer can be reduced even at low temperatures.
In general formula (Ia) and general formula (Ib), R ¹ and R ² are an alkyl group having 1 to 5 carbon atoms or an alkenyl group having 2 to 6 carbon atoms (present in the alkyl group or alkenyl group). One or two or more CH ₂ groups may be substituted with an oxygen atom as O atoms are not directly bonded to each other), and the alkenyl group is represented by the formula (Va)

(構造式は右端で直接もしくは酸素原子を介して環に連結しているものとする。)で表されるものが好ましく、炭素原子数1から5のアルキル基がより好ましい。
A¹及びA²としては、1,4-シクロヘキシレン基が好ましく、
Z¹及びZ²としては、単結合が好ましく、
X¹及びX²としては、フッ素原子もしくはトリフルオロメトキシ基が好ましく、フッ素原子がより好ましい。
具体的には一般式（V-1）から一般式（V-42）で表される化合物が好ましい。

(The structural formula is assumed to be connected to the ring directly or through an oxygen atom at the right end), and an alkyl group having 1 to 5 carbon atoms is more preferable.
A ¹ and A ² are preferably 1,4-cyclohexylene groups,
Z ¹ and Z ² are preferably single bonds,
X ¹ and X ² are preferably a fluorine atom or a trifluoromethoxy group, and more preferably a fluorine atom.
Specifically, compounds represented by general formula (V-1) to general formula (V-42) are preferable.

(In the formula, R ¹¹ represents an alkyl group having 1 to 5 carbon atoms.)
In the general formula (Ic), R ²¹ represents an alkyl group having 1 to 5 carbon atoms or an alkenyl group having 2 to 6 carbon atoms (one or two or more CH ₂ present in the alkyl group or alkenyl group). The group may be substituted with an oxygen atom as O atoms are not directly bonded to each other.), Preferably an alkyl group having 1 to 5 carbon atoms or an alkoxy group having 1 to 5 carbon atoms .
Z ²¹ is preferably a single bond,
X ⁵¹ is preferably an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or a fluorine atom,
X ⁵² to X ⁵⁷ are preferably a hydrogen atom, a fluorine atom or a methyl group, and more preferably one or more and three or less of X ⁵² to X ⁵⁷ are a fluorine atom or a methyl group.
Specifically, from general formula (I-41) to general formula (I-47)

(Wherein R ³¹ , R ³² and R ³³ each independently represents an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms,
X ⁶¹ to X ⁶⁶ each independently represent a hydrogen atom, a fluorine atom, or a methyl group,
X ⁷¹ to X ⁷⁶ each independently represent a hydrogen atom or a fluorine atom. )
Of these, preferred is a compound represented by: at least one of X ⁶¹ to X ⁶⁶ , three or less being a fluorine atom or a methyl group, and at least one or more of X ⁷¹ to X ⁷⁶ , 3 More preferably, no more than one is a fluorine atom. Specifically, from general formula (I-51) to general formula (I-59)

(Wherein R ³⁵ , R ³⁶ and R ³⁷ each independently represents an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms,
X ⁸¹ , X ⁸⁴ , X ⁸⁵ and X ⁸⁶ each independently represent a hydrogen atom or a fluorine atom, and X ⁸² and X ⁸³ each independently represent a hydrogen atom, a fluorine atom or a methyl group, (I-55) and at least one or more of X ⁸² to X ⁸⁶ in formula (I-56) represent a fluorine atom or a methyl group,
X ⁸⁷ and X ⁸⁸ each independently represent a hydrogen atom or a fluorine atom. )
Even more preferred is a compound represented by:
In addition to the compounds of general formula (Ia), general formula (Ib) and general formula (Ic), in addition to the compounds of general formula (III-a), in order to obtain further expansion of the liquid crystal temperature range, high dielectric constant, or low viscosity, Or a compound represented by the general formula (IV-a).
In the general formula (III-a), R ³ and R ⁴ are each an alkyl group having 1 to 5 carbon atoms or an alkenyl group having 2 to 6 carbon atoms (one or 2 present in the alkyl group or alkenyl group). More than one CH ₂ group may be substituted with an oxygen atom as O atoms are not directly bonded to each other. The alkenyl group is preferably a group represented by the formula (Va), carbon Even more preferred are alkyl or alkoxy groups of 1 to 5 atoms.
In particular, when it is desired to obtain low viscosity, n ³ is 0, A ⁴ and A ⁵ are preferably 1,4-cyclohexylene groups, and Z ⁶ is preferably a single bond,
In particular, in order to expand the liquid crystal temperature range, n ³ is 0 or 1, A ³ and A ⁴ are 1,4-cyclohexylene groups, and A ⁵ is 1,4-phenylene group (the 1,4 The -phenylene group is unsubstituted or may have one or more fluorine atoms or methyl groups as substituents), and Z ⁵ is a single bond or —CH ₂ CH ₂ —; Z ⁶ is preferably a single bond,
In particular, in order to obtain a high refractive index, n ³ is 1 and A ³ is 1,4-cyclohexylene group or 1,4-phenylene group (the 1,4-phenylene group is unsubstituted or substituted) 1 or 2 or more fluorine atoms or a methyl group as a group), and A ⁴ and A ⁵ are 1,4-phenylene groups (is the 1,4-phenylene group unsubstituted)? Alternatively, it may have one or two or more fluorine atoms or methyl groups as a substituent.
Specifically, compounds represented by general formula (III-1) to general formula (III-5) are preferable.

(Wherein R ¹² and R ¹³ are each independently an alkyl group having 1 to 5 carbon atoms, (one or two or more CH ₂ groups present in the alkyl group have O atoms directly connected to each other) And may be substituted with an oxygen atom as a non-bonded group.), And X ²¹ to X ²⁶ each independently represents a hydrogen atom, a fluorine atom or a methyl group.)
R ^{5 in the} general formula (IV-a) is an alkyl group having 1 to 5 carbon atoms or an alkenyl group having 2 to 6 carbon atoms (one or two or more present in the alkyl group or alkenyl group). The CH ₂ group may preferably be substituted with an oxygen atom as O atoms are not directly bonded to each other.) The alkenyl group is preferably represented by the formula (Va), and has 1 carbon atom. Even more preferred are alkyl groups of 1 to 5 or alkoxy groups of 1 to 5 carbon atoms.
X ¹³ is preferably a fluorine atom or a trifluoromethoxy group, and more preferably a fluorine atom.

In particular, when it is desired to obtain a high dielectric constant, n ⁴ is 0 or 1, A ⁶ is a 1,4-cyclohexylene group, A ⁷ is a 1,4-cyclohexylene group, or 1, A 4-phenylene group (the 1,4-phenylene group is unsubstituted or may have one or more fluorine atoms or a methyl group as a substituent), and A ⁸ is 2-fluoro A 1,4-phenylene group, a 3-fluoro-1,4-phenylene group, a 2,6-difluoro-1,4-phenylene group or a 3,5-difluoro-1,4-phenylene group, and Z ⁷ and Z ⁸ is preferably a single bond.
In particular, to extend the liquid crystal temperature range, n ³ is 2, A ⁶ is 1,4-cyclohexylene group, and A ⁷ is 1,4-cyclohexylene group or 1,4-phenylene group And A ⁸ is 2-fluoro-1,4-phenylene group, 3-fluoro-1,4-phenylene group, 2,6-difluoro-1,4-phenylene group or 3,5-difluoro-1,4 It is preferably a -phenylene group, and Z ⁷ and Z ⁸ are preferably a single bond or —CH ₂ CH ₂ —.
Specifically, compounds represented by general formula (IV-1) to general formula (IV-4) are preferable.

(Wherein R ¹⁴ represents an alkyl group or alkoxy group having 1 to 5 carbon atoms, X ³¹ to X ³⁴ represent a hydrogen atom or a fluorine atom, Z ¹¹ represents a single bond, —CH ₂ CH ₂ — or — Represents COO-)
Among these general formulas (IV-1) to (IV-4), compounds represented by general formulas (IV-5) to (IV-8) are more preferable.

(In the formula, R ¹⁵ represents an alkyl group having 1 to 5 carbon atoms, and X ³⁵ to X ³⁷ each independently represents a hydrogen atom or a fluorine atom.)
These liquid crystal compositions may be subjected to a purification treatment with silica, alumina or the like for the purpose of removing impurities or the like or further increasing the specific resistance value. The specific resistance value is preferably 10 ¹² Ω · cm or more, and more preferably 10 ¹³ Ω · cm or more.
Furthermore, dopants such as chiral compounds and dyes can be added to the liquid crystal composition according to the purpose.

The polymerizable compound is a compound that forms a transparent polymer substance in the light control layer formed in the polymer dispersion type liquid crystal display element, and is polymerizable by polymerizing this compound with heat or active energy rays. The compatibility between the compound and the low-molecular liquid crystal changes to cause two-phase separation, and the polymerizable compound and the low-molecular liquid crystal form a fine phase-separated structure on the order of submicron to obtain the desired transparent polymer substance. Can do. In order to achieve a low driving voltage in a low temperature region of a polymer dispersion type liquid crystal display element, it is not sufficient to achieve a wide liquid crystal temperature range of the liquid crystal composition. A combination having a low anchoring energy between the liquid crystal composition and the transparent polymer material must be found. As for the anchoring energy, in the transparent polymer material, the alkyl side chain length and the main chain of the alkylene group have a great influence on the anchoring energy, but the molecular mobility to heat of the side chain and the main chain Moreover, the anchoring energy is greatly affected. For example, at a high temperature, the side chain fluctuates greatly due to heat, and when the kinetic energy due to this fluctuation is larger than the anchoring energy, the intermolecular interaction between the liquid crystal and the polymer is small and the driving voltage is lowered. When the kinetic energy at which the temperature decreases and the side chain thermal fluctuation decreases becomes smaller than the anchoring energy, the intermolecular interaction increases and the driving voltage increases. However, if the glass transition temperature (Tg) of the polymer is lowered so that the molecular mobility does not decrease even at low temperatures, an increase in driving voltage at low temperatures can be suppressed. Specifically, Tg can be lowered by elongating the main chain length of the transparent polymer substance to increase the distance between crosslinks or by introducing a methyl group or an ethyl group into a part of the main chain. A low driving voltage at a low temperature of −20 ° C. or lower can be realized by selecting a liquid crystal having a low anchoring energy and using the above-described transparent polymer substance. Specifically, it is preferable that the surface energy of the transparent polymer material is equivalent to that of the liquid crystal composition even in a low temperature range. Such a transparent polymer material is composed of a polymerizable compound represented by the general formula (II-b). Obtainable. Due to the presence of the partial structure represented by the general formula (II-a) present in this compound, the surface energy of the transparent polymer substance can be controlled, and low voltage driving in a low temperature range is realized.

B ⁵ , B ⁶ and B ^{7 in the} general formula (II-b) are preferably a combination of alkylene groups in which the total number of carbon atoms of B ⁵ , B ⁶ and B ⁷ is 5 to 31, A combination of alkylene groups with a total of 5 to 20 is more preferable, a combination of alkylene groups with a total number of carbon atoms of 10 to 15 is more preferable, and 2 or more and 6 or less CH ₂ groups of the alkylene groups are oxygen An alkylene group substituted with an atom is preferable, and two CH ₂ groups are more preferably substituted with an oxygen atom. M and n are preferably 1, an alkylene group having 5 to 15 carbon atoms in which m and n are 1 and the total number of B ⁵ , B ⁶ and B ⁷ carbon atoms, and two CH ₂ groups of the alkylene group are oxygen More preferably, it is substituted with an atom.
The number of substituents of the general formula (II-a) present in B ⁵ , B ⁶ and B ⁷ is preferably 2 to 4, more preferably 2. B ¹ and B ² may be linear or branched, but when linear, at least one is preferably an alkyl group having 5 to 16 carbon atoms, More preferably (one or more CH ₂ groups present in the alkyl group are substituted with oxygen atoms, —CO—, —COO—, —OCO—, as oxygen atoms are not directly bonded to each other). May be). Even more preferred is one in which one CH ₂ group in the alkyl group is substituted with —COO—.

In the case of having a branched chain, the main chain in at least one branched chain is preferably an alkyl group having 5 to 16 carbon atoms, more preferably 10 to 14 (one existing in the alkyl group) Alternatively, two or more CH ₂ groups may be substituted with oxygen atoms, —CO—, —COO—, —OCO—, in which oxygen atoms are not directly bonded to each other). Even more preferred is one in which one CH ₂ group in the alkyl group is substituted with —COO—.
B ³ and B ⁴ are preferably hydrogen atoms.
Furthermore, as the polymerizable compound, a compound represented by the general formula (II-c)

(In the formula, B ⁸ , B ⁹ and B ¹⁰ each independently represents a single bond or an alkylene group having 1 to 19 carbon atoms, and one or more CH ₂ groups present in the alkylene group are The oxygen atoms may be substituted with oxygen atoms, -CO-, -COO- or -OCO- as those in which the oxygen atoms are not directly bonded to each other, but the total number of carbon atoms of B ⁸ , B ⁹ and B ¹⁰ is 3 29 and
B ¹¹ and B ¹³ each independently represent an alkyl group having 2 to 25 carbon atoms, and one or more CH ₂ groups present in the alkyl group are those in which oxygen atoms are not directly bonded to each other. May be substituted with an oxygen atom, -CO-, -COO- or -OCO-,
B ¹² and B ¹⁴ each independently represent a hydrogen atom or an alkyl group having 1 to 25 carbon atoms, and one or more CH ₂ groups present in the alkyl group have oxygen atoms directly connected to each other. It may be substituted with an oxygen atom, -CO-, -COO- or -OCO- as a non-bonded one. )
In the general formula (II-c), the total number of carbon atoms of B ⁸ , B ⁹ and B ¹⁰ is 5 to 29, and B ¹¹ and B ¹³ are alkyl groups having 5 to 25 carbon atoms (the alkyl (One or two or more CH ₂ groups present in the group may be substituted with an oxygen atom, —CO—, —COO— or —OCO— assuming that the oxygen atoms are not directly bonded to each other.) Wherein B ¹² and B ¹⁴ are hydrogen atoms or alkyl groups having 1 to 5 carbon atoms (one or more CH ₂ groups present in the alkyl groups are such that oxygen atoms are not directly bonded to each other) More preferably an oxygen atom, -CO-, -COO- or -OCO-).

In the general formula (II-c), the total number of carbon atoms of B ⁸ , B ⁹ and B ¹⁰ is 8 to 29, and B ¹¹ and B ¹³ are linear alkyl groups having 8 to 16 carbon atoms. , One CH ² group in the alkyl group is substituted with —COO—, or B ¹¹ and B ¹³ are branched alkyl groups, and the alkyl group has 8 to 16 carbon atoms in the main chain. A group in which one CH ² group in the alkyl group is substituted with —COO—, and B ¹² and B ¹⁴ are a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, preferable.

  Specifically, a compound of the general formula (II-d) is preferable.

(Wherein p and r represent 0 or 1, q represents 2 to 20, s and t represent 0, 1, 2 or 3, and B ²¹ and B ²² have 6 to 14 carbon atoms. A straight-chain alkyl group or an alkyl group having a branched chain of 7 to 23 carbon atoms having 6 to 14 carbon atoms in the main chain, B ²³ and B ²⁴ are hydrogen atoms or 1 carbon atom To Y. Y1 and Y2 each independently represent a hydrogen atom, a methyl group or an ethyl group.) Furthermore, the compound of the general formula (II-e) or the general formula (II-f) is more preferable.

In general formula (II-c), general formula (II-e), and general formula (II-f), when q is 3 or more, each of Y1 and Y2 is independently a methyl group or an ethyl group. Can be combined. In addition, it is particularly preferable to combine one or two because an increase in driving voltage at a low temperature is suppressed.
As the polymerizable compound that forms the transparent polymer substance of the polymer dispersed liquid crystal, one or more of the above polyfunctional polymerizable compounds can be used, and it can be used in combination with the monofunctional polymerizable compound. However, when used in combination with a monofunctional polymerizable compound, there is a possibility that an unpolymerized polymerizable compound may remain, which may cause a change in characteristics over time, a deterioration in reliability, and the like. Are preferably composed only of the compound represented by general formula (II-c), more preferably are composed of only the compound represented by general formula (II-d). Even more preferred.

As the polymerizable compound that forms the transparent polymer substance of the polymer dispersed liquid crystal, one or more of the above polyfunctional polymerizable compounds can be used, and it can be used in combination with the monofunctional polymerizable compound. However, when used in combination with a monofunctional polymerizable compound, a large amount of unpolymerized polymerizable compound may remain. In this case, ultraviolet rays, heat, etc. are added so as to reduce the remaining amount of the unpolymerized polymerizable compound to promote the reaction of the monomer remaining in the produced liquid crystal, and the remaining amount can be reduced. What consists only of the compound represented by general formula (II-b) is preferable, and what consists only of the compound represented by general formula (II-c) is more preferable, and general formula (II-d) Even more preferred are those composed of a compound represented by the formula:

In consideration of the condition that the radical polymerizable compound does not volatilize due to the vacuum injection condition during the manufacturing process of the polymer dispersion type liquid crystal display element, the molecular weight of the polymerizable compound is preferably 300 to 1500, and preferably 500 to 1000. More preferred. Furthermore, it is preferable that the surface energy of the transparent polymer material obtained by curing a polymerizable compound is 40 mN / m ² to 20, and more preferably a 37 mN / m ² to 27.
These polymerizable compounds may be subjected to a purification treatment with silica, alumina or the like for the purpose of removing impurities or increasing the high specific resistance value. The specific resistance value is preferably 10 ¹¹ Ω · cm or more, more preferably 10 ¹² Ω · cm or more, and most preferably 10 ¹³ Ω · cm or more.

As a polymerization method, radical polymerization, anionic polymerization, cationic polymerization, and the like can be used, but polymerization is preferably performed by radical polymerization.
As the radical polymerization initiator, a thermal polymerization initiator or a photopolymerization initiator can be used, but a photopolymerization initiator is preferable. Specifically, the following compounds are preferable.
Diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzyldimethyl ketal, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, 4- ( 2-hydroxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone, 1-hydroxycyclohexyl-phenylketone, 2-methyl-2-morpholino (4-thiomethylphenyl) propan-1-one, 2-benzyl- Acetophenone series such as 2-dimethylamino-1- (4-morpholinophenyl) -butanone;
Benzoins such as benzoin, benzoin isopropyl ether and benzoin isobutyl ether; Acylphosphine oxides such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide; Benzyl and methylphenylglyoxyesters;
Benzophenone, methyl o-benzoylbenzoate, 4-phenylbenzophenone, 4,4'-dichlorobenzophenone, hydroxybenzophenone, 4-benzoyl-4'-methyl-diphenyl sulfide, acrylated benzophenone, 3,3 ', 4,4' -Benzophenone series such as tetra (t-butylperoxycarbonyl) benzophenone, 3,3'-dimethyl-4-methoxybenzophenone;
Thioxanthone systems such as 2-isopropylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone;
Aminobenzophenone series such as Michler's ketone and 4,4′-diethylaminobenzophenone;
10-butyl-2-chloroacridone, 2-ethylanthraquinone, 9,10-phenanthrenequinone, camphorquinone and the like are preferable.
Of these, benzyldimethyl ketal is most preferred.

59 to 89% by mass of a liquid crystal composition comprising a compound selected from the group of compounds represented by general formula (Ia) and general formula (Ib) and a compound group represented by general formula (Ic), It is preferable that the polymerizable compound represented by II-b) is contained in an amount of 10 to 40% by mass and the polymerization initiator is contained in an amount of 0.1 to 2% by mass, and is represented by the general formula (Ia) and the general formula (Ib). A liquid crystal composition comprising a compound selected from the compound group and a compound group represented by the general formula (Ic) is contained in an amount of 63 to 75% by mass, and the polymerizable compound represented by the general formula (II-b) is from 24 to 36 More preferably, the content of the polymerization initiator is 0.1 to 2% by mass. As the composition of the liquid crystal composition, the content of the compound group represented by the general formula (Ia) and the general formula (Ib) is 10 to 60%, and the content of the compound represented by the general formula (Ic) is 10 60% is preferable, the content of the compound group represented by the general formula (Ia) and the general formula (Ib) is 15 to 50%, and the content of the compound represented by the general formula (Ic) is 20 What is 50% is more preferable.

A method for manufacturing a polymer-dispersed liquid crystal display element will be described. The polymer-dispersed liquid crystal display element of the present invention has a composition for polymer-dispersed liquid crystal display elements of the present invention sandwiched between two substrates, at least one of which is transparent, and then heat or active energy rays. It is obtained by polymerizing the polymerizable compound by irradiation and inducing phase separation from the liquid crystal composition to form a light control layer composed of the liquid crystal composition and a transparent polymer substance.
The two substrates can be made of a transparent material having flexibility such as glass and plastic, and one of them can be an opaque material such as silicon. Functions such as light absorption, specular reflection, diffuse reflection, retroreflection, and hologram reflection can also be added. The glass substrate surface can be coated with polyimide or the like.
A spacer for maintaining a gap can be interposed between the two substrates, as in a known liquid crystal device. The thickness between the substrates, that is, the thickness of the light control layer is preferably 2 to 30 μm, more preferably 2 to 10 μm, and even more preferably 3 to 6 μm.
As a method for sandwiching the polymer-dispersed liquid crystal display element composition between two substrates, a normal vacuum injection method, an ODF method, or the like can be used. At this time, the polymer-dispersed liquid crystal display element composition is preferably in a uniform isotropic state.
As a method for polymerizing the radically polymerizable compound, ultraviolet irradiation is suitable. As a lamp for generating ultraviolet rays, a metal halide lamp, a high-pressure mercury lamp, an ultra-high pressure mercury lamp, or the like can be used. Further, the wavelength of the ultraviolet rays to be irradiated is an absorption wavelength region of the photopolymerization initiator contained in the polymer-dispersed liquid crystal display element composition, and a wavelength that is not the absorption wavelength region of the contained liquid crystal composition. It is preferable to irradiate ultraviolet rays in the region. Specifically, it is preferable to cut and use ultraviolet rays of 330 nm or less using a metal halide lamp, high-pressure mercury lamp, or ultra-high pressure mercury lamp, and cut ultraviolet rays of 350 nm or less. And more preferably used.

Intensity of ultraviolet light irradiation, can be appropriately adjusted to obtain a light control layer of interest, preferably 200 mw / cm ² from 1, 2 to 100 mw / cm ² is more preferable. The time for irradiation with ultraviolet rays is appropriately selected depending on the intensity of ultraviolet rays to be irradiated, but is preferably 10 to 600 seconds. More preferably, it is preferable to ultraviolet exposure so as to ^{1200mJ / cm 2 ~2400mJ / cm 2} .
The temperature at the time of ultraviolet irradiation is an important factor that determines the characteristics of the light control layer, but is preferably slightly higher than the isotropic-nematic transition point of the polymer dispersed liquid crystal display element composition. Specifically, the transition point +0.1 to 3 ° C. is preferable.
The light control layer in the polymer-dispersed liquid crystal display device manufactured by the above-described method or other methods has a structure in which the liquid crystal composition is confined in a capsule shape with a transparent polymer substance. It has a structure in which a three-dimensional network structure of a transparent polymer substance is formed in the continuous phase, or a structure in which both are mixed, but the three-dimensional structure of the transparent polymer substance in the continuous phase of the liquid crystal composition. A structure in which a network structure is formed is preferable, and a structure in which a three-dimensional network structure of a transparent polymer substance is formed in the continuous phase of the liquid crystal composition by ultraviolet irradiation is more preferable.
The average gap spacing of the network structure greatly affects the characteristics of the polymer dispersion type liquid crystal display element, and the average gap spacing is preferably 0.2 to 2 μm, more preferably 0.2 to 1 μm, and most preferably 0.3 to 0.7 μm.
The polymer-dispersed liquid crystal display element of the present invention is characterized by a low driving voltage at a low temperature. V90 at a cell thickness of 5 μm is preferably 7.5 V or less, more preferably 6.5 V or less.

EXAMPLES Hereinafter, although an Example is given and this invention is further explained in full detail, this invention is not limited to these Examples. Further, “%” in the compositions of the following examples and comparative examples means “mass%”.
The polymer dispersion type liquid crystal display elements in the examples were produced by the following method.
A composition for a polymer-dispersed liquid crystal display element comprising a liquid crystal composition, a polymerizable compound and a photopolymerization initiator was injected into a glass cell with ITO having a cell thickness of 5 μm by a vacuum injection method. At this time, the temperature in the vacuum injection apparatus was controlled so that the composition for the polymer-dispersed liquid crystal display element was always in a uniform state. The degree of vacuum was set to 2 pascals. After the injection, the glass cell was taken out and the inlet was sealed with a sealing agent 3026E (manufactured by ThreeBond Co., Ltd.), and then the temperature was controlled at 1 to 2 ° C. higher than the isotropic-nematic transition point of the polymer dispersion type liquid crystal display element composition. The polymer halide liquid crystal display device was obtained by irradiating with a metal halide lamp adjusted to an irradiation intensity of 10 mw / cm ² through an ultraviolet cut filter UV-35 (manufactured by Toshiba Glass Co., Ltd.) for 120 seconds. .
Abbreviations and meanings of characteristics of the liquid crystal compositions shown in the examples are as follows.

TN-I: Nematic phase-isotropic liquid phase transition temperature (℃)
T → N: Solid phase or smectic phase-nematic phase transition temperature (℃)
The liquid crystal temperature range (nematic liquid crystal temperature range) means from the solid phase or smectic phase-nematic phase transition temperature to the nematic phase-isotropic phase transition temperature unless otherwise specified.

Abbreviations and meanings of characteristics of the polymer dispersed liquid crystal display elements shown in the examples are as follows.
V10: Light transmittance (T100) when the light transmittance (T0) of the polymer-dispersed liquid crystal display element when no voltage is applied is 0%, and the light transmittance hardly changes as the applied voltage is increased. The applied voltage value at which the light transmittance is 10%, where is 100%.
V90: Light transmittance (T100) when the transmittance of the polymer dispersed liquid crystal display element when no voltage is applied is 0% and the applied voltage is increased and the light transmittance hardly changes. The applied voltage value at which the light transmittance is 90%, where is 100%.
The voltage holding ratio (VHR) is measured using the liquid crystal voltage holding ratio measurement system VHR-A1 (manufactured by Toyo Technica), the pulse width is 64 μsec, the frame period is 16.67 msec, the applied voltage is 5 V, and the area ratio is obtained. It was.
(Example 1)
A composition for a polymer dispersed liquid crystal display device comprising 70% of a liquid crystal composition (A), 29.4% of a radical polymerizable compound (X), and 0.6% of a photopolymerization initiator Irgacure 651 (manufactured by Ciba Specialty Chemicals). And a polymer-dispersed liquid crystal display element was obtained by the method described above. The liquid crystal temperature range of the liquid crystal composition (A) was −32 to 86.3 ° C., and V90 of this device was 5V at 25 ° C., 5V at 0 ° C., and 5.2V at −10 ° C. The voltage holding ratio (VHR) was 98.5%.

(Example 2)
The liquid crystal composition (A) in Example 1 was changed to (B), and the polymer compound type liquid crystal display element was obtained by the same method using (X) as the radical polymerizable compound in Example 1. The liquid crystal temperature range of the liquid crystal composition (B) was −37 ° C. to 79.2 ° C. The V90 of this device was 3.2 V at 25 ° C., 2.9 V at 0 ° C., and 3.1 V at −10 ° C. The voltage holding ratio (VHR) was 98.9%.

(Example 3)
The radical polymerizable compound (X) in Example 2 was changed to (Y), and a polymer dispersion type liquid crystal display device was obtained by the same method. V90 of this element was 5.9 V at 25 ° C., 6.8 V at 0 ° C., and 7.3 V at −10 ° C. The voltage holding ratio (VHR) was 98.7%.

(Example 4)
The radical polymerizable compound (X) in Example 2 was changed to (Z), and a polymer dispersion type liquid crystal display device was obtained by the same method. V90 of this element was 4.0 V at 25 ° C., 3.7 V at 0 ° C., and 3.6 V at −10 ° C. The voltage holding ratio (VHR) was 99.0%.

(Example 5)
The radical polymerizable compound (X) in Example 2 was changed to (ZA), and a polymer dispersion type liquid crystal display device was obtained by the same method. V90 of this element was 3.3 V at 25 ° C., 2.9 V at 0 ° C., and 2.8 V at −10 ° C. Furthermore, it was driven at 5.5V even at -20 ° C. The voltage holding ratio (VHR) was 99.1%.

(Comparative Example 1)
The liquid crystal composition (A) in Example 1 was changed to (L), and a polymer dispersion type liquid crystal display device was obtained in the same manner. The liquid crystal temperature range of the liquid crystal composition (L) was −5 to 95.5 ° C., and V90 of this device was 6.0 V at 25 ° C., 6.8 V at 0 ° C., and 15.0 V at −10 ° C. The voltage holding ratio (VHR) was 98.8%.

(Comparative Example 2)
Liquid crystal composition (L) is 70%, radical polymerizable compound A-OCD (made by Shin-Nakamura Chemical) 17.64%, lauryl acrylate (LA) 11.76%, photopolymerization initiator Irgacure 651 (made by Ciba Specialty Chemicals) A composition for a polymer-dispersed liquid crystal display element comprising 0.6% was prepared, and a polymer-dispersed liquid crystal display element was obtained by the method described above. V90 of this element was 3.6 V at 25 ° C., 4.5 V at 0 ° C., and 18.3 V at −10 ° C. The voltage holding ratio (VHR) was 98.5%.
(Comparative Example 3)
The liquid crystal composition (A) in Example 1 was changed to (M), and a polymer dispersion type liquid crystal display device was obtained in the same manner. The liquid crystal temperature range of the liquid crystal composition (M) was 24 to 109.5 ° C., and V90 of this device was 5.1 V at 25 ° C., 5.3 V at 0 ° C., and 6.5 V at −10 ° C. The voltage holding ratio (VHR) was 60.3%.

  Evaluation of liquid crystal compositions used in the above examples and comparative examples, their liquid crystal temperature ranges, used radical polymerizable compounds, photopolymerization initiators, and properties of polymer dispersed liquid crystal display devices obtained using these The results are summarized in Table 1.

表１より、トラン系の液晶化合物のみを用いた比較例１の高分子分散型液晶表示素子は低温におけるV90が高い問題がある。液晶化合物にトラン系の材料を用い、重合性化合物として一般式(II-b)で表される化合物を用いない比較例2の高分子分散型液晶表示素子はV90が高い。シアノ系の液晶材料を用いた比較例3の高分子分散型液晶表示素子は電圧保持率が著しく低くアクティブ駆動用としての使用は困難である。

From Table 1, the polymer-dispersed liquid crystal display element of Comparative Example 1 using only a tolan-based liquid crystal compound has a problem of high V90 at low temperatures. The polymer-dispersed liquid crystal display element of Comparative Example 2, which uses a tolan-based material as the liquid crystal compound and does not use the compound represented by the general formula (II-b) as the polymerizable compound, has a high V90. The polymer dispersed liquid crystal display element of Comparative Example 3 using a cyano liquid crystal material has a remarkably low voltage holding ratio and is difficult to use for active driving.

Compared with these, when a liquid crystal composition containing a tolan-based liquid crystal as a main component contains a tetralin-based liquid crystal compound, the polymer dispersed liquid crystal display elements of Examples 1 to 5 have a low driving voltage at −10 ° C. and are of Comparative Example 1. , 2 have no rapid increase and have excellent temperature characteristics. In particular, in Examples 2 and 4 containing 15% of a tetralin-based liquid crystal compound, it can be seen that even when the driving voltage is −10 ° C., it is as low as 4 V or less and the voltage holding ratio (VHR) is high.

Claims (10)

General formula (Ia) and general formula (Ib)

(In the formula, R ¹ and R ² each independently represents an alkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, and one or more present in the alkyl group or alkenyl group or Two or more CH ₂ groups may be substituted with oxygen atoms, assuming that the oxygen atoms are not directly bonded to each other,
A ¹ , A ² and A ³ each independently represents a 1,4-phenylene group or a 1,4-cyclohexylene group, and the 1,4-phenylene group is unsubstituted or has one substituent. Or two or more fluorine atoms, chlorine atoms, methyl groups or trifluoromethyl groups or trifluoromethoxy groups,
X ¹ and X ⁷ each independently represent a fluorine atom, a chlorine atom, an isocyanate group, a trifluoromethyl group, a trifluoromethoxy group or a difluoromethoxy group,
X ² to X ⁵ and X ⁸ to X ¹⁰ each independently represent a hydrogen atom, a fluorine atom, a chlorine atom, a trifluoromethyl group or a trifluoromethoxy group, and X ¹¹ and X ¹² each independently represent a hydrogen atom. Represents an atom, a fluorine atom, a chlorine atom, a trifluoromethyl group or a trifluoromethoxy group, and when A2 represents a 1,4-cyclohexylene group, X ¹¹ and X ¹² represent a hydrogen atom,
Z ¹ and Z ³ each independently represent a single bond, —CH ₂ —CH ₂ — or —COO—,
Z ² and Z ⁴ each independently represent a single bond, —CH ₂ —CH ₂ — or —CF ₂ O—,
n ¹ and n ² represent 0 or 1. )
Containing at least one compound from the group of compounds represented by formula (Ic)

(Wherein R ²¹ represents an alkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, and one or more CH ₂ groups present in the alkyl group or alkenyl group are , As oxygen atoms are not directly bonded to each other, may be substituted with oxygen atoms,
A ²¹ represents a 1,4-phenylene group or a 1,4-cyclohexylene group, and the 1,4-phenylene group is unsubstituted or substituted with one or more fluorine atoms, chlorine atoms, Can have a methyl group or a trifluoromethyl group or a trifluoromethoxy group,
Z ²¹ represents a single bond or —CH ₂ —CH ₂ —, —COO—, —CF ₂ O—,
X ⁵¹ represents an alkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms (one or two or more CH ₂ groups present in the alkyl group or alkenyl group have an oxygen atom And may be substituted with an oxygen atom as a group not directly bonded to), a fluorine atom, a chlorine atom, an isocyanate group, a trifluoromethyl group, a trifluoromethoxy group, a difluoromethoxy group, or a general formula (Id),

(In the formula, A ²² represents a 1,4-phenylene group or a 1,4-cyclohexylene group, and the 1,4-phenylene group is unsubstituted or has one or more fluorine atoms as a substituent. A chlorine atom, a methyl group or a trifluoromethyl group or a trifluoromethoxy group,
X ⁶⁰ represents an alkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms (one or two or more CH ₂ groups present in the alkyl group or alkenyl group have an oxygen atom And a fluorine atom, a chlorine atom, an isocyanate group, a trifluoromethyl group, a trifluoromethoxy group, or a difluoromethoxy group. )
X ⁵² to X ⁵⁷ each independently represent a hydrogen atom, a fluorine atom, a chlorine atom, a trifluoromethyl group, a trifluoromethoxy group, a methyl group, a methoxy group or an ethyl group,
n ¹⁰ represents 0 or 1. )
Containing at least one compound selected from the group of compounds represented by formula (II-b)

(In the formula, B ⁵ , B ⁶ and B ⁷ each independently represents a single bond or an alkylene group having 1 to 19 carbon atoms, and the alkylene group is unsubstituted or has one or two substituents. It may have the above fluorine atom, methyl group, and ethyl group, and one or two or more CH ₂ groups present in the alkylene group are oxygen atoms on the assumption that oxygen atoms are not directly bonded to each other. , -CO-, -COO-, -OCO-, 1,4-phenylene group, pyridine-2,5-diyl group, pyrimidine-2,5-diyl group, 1,3-dioxane-2,5-diyl group 1,4-cyclohexylene group, bicyclo [2.2.2] octane-1,4-diyl group or 3,3′-spirobicyclobutylene may be substituted, and the 1,4-phenylene group is unsubstituted Or one or more fluorine atom, chlorine atom, methyl group, trifluoromethyl group or trifluoromethyl as a substituent. Can have a carboxy group, at least one or more CH ₂ groups in the alkylene group is general formula (II-a)

(Wherein B ¹ represents an alkyl group having 2 to 30 carbon atoms, and the alkyl group may be unsubstituted or may have one or more fluorine atoms as a substituent; One or more CH ₂ groups present in the alkyl group are oxygen atoms, —CO—, —COO—, —OCO—, 1,4-phenylene groups, as oxygen atoms are not directly bonded to each other, Pyridine-2,5-diyl group, pyrimidine-2,5-diyl group, 1,3-dioxane-2,5-diyl group, 1,4-cyclohexylene group, bicyclo [2.2.2] octane-1,4 Optionally substituted with a -diyl group or 3,3'-spirobicyclobutylene,
B ² represents a hydrogen atom or an alkyl group having 1 to 30 carbon atoms, and the alkyl group may be unsubstituted or have one or more fluorine atoms as a substituent. One or more CH ₂ groups present in the group are oxygen atoms, —CO—, —COO—, —OCO—, 1,4-phenylene groups, pyridines, as oxygen atoms are not directly bonded to each other. -2,5-diyl group, pyrimidine-2,5-diyl group, 1,3-dioxane-2,5-diyl group, 1,4-cyclohexylene group, bicyclo [2.2.2] octane-1,4- It may be substituted with a diyl group or 3,3′-spirobicyclobutylene. )
And the total number of carbon atoms of B ⁵ , B ⁶ and B ⁷ is 5 or more,
B ³ and B ⁴ each independently represent a hydrogen atom or a methyl group,
m and n each independently represent 1, 2 or 3. )
A composition for a polymer-dispersed liquid crystal element, comprising a polymerizable compound represented by the formula (1) and further containing a polymerization initiator. The compound represented by the general formula (II-b) is represented by the general formula (II-c)

(In the formula, B ⁸ , B ⁹ and B ¹⁰ each independently represent a single bond or an alkylene group having 1 to 19 carbon atoms, and one or two or more CH ₂ groups present in the alkylene group. May be substituted with an oxygen atom, -CO-, -COO-, or -OCO- as those in which the oxygen atoms are not directly bonded to each other, but one or more hydrogen substitutions present in the alkylene group The group may be substituted with a methyl group or an ethyl group, and the total number of carbon atoms of B ⁸ , B ⁹ and B ¹⁰ excluding the methyl group and the ethyl group is 3 to 29, and B ¹¹ and B ¹³ are Each independently represents an alkyl group having 2 to 25 carbon atoms, and one or two or more CH ₂ groups present in the alkyl group are defined as oxygen atoms, —CO -, -COO- or -OCO- may be substituted,
B ¹² and B ¹⁴ each independently represent a hydrogen atom or an alkyl group having 1 to 25 carbon atoms, and one or more CH ₂ groups present in the alkyl group have oxygen atoms directly connected to each other. It may be substituted with an oxygen atom, -CO-, -COO- or -OCO- as a non-bonded one. )
The composition for a polymer-dispersed liquid crystal element according to claim 1, represented by: General formula (III-a)

(Wherein R ³ and R ⁴ each independently represents an alkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, Two or more CH ₂ groups may be substituted with oxygen atoms, assuming that the oxygen atoms are not directly bonded to each other,
A ³ , A ⁴ and A ⁵ each independently represents a 1,4-phenylene group or a 1,4-cyclohexylene group, and the 1,4-phenylene group is unsubstituted or represents one or more substituents Can have two or more fluorine atoms, chlorine atoms, methyl groups or trifluoromethyl groups or trifluoromethoxy groups;
Z ⁵ and Z ⁶ each independently represent a single bond or —CH ₂ CH ₂ —, —COO—,
n ³ represents 0, 1 or 2. However, when n ³ = 2, a plurality of A ³ and Z ⁵ may be the same or different. )
The composition for polymer-dispersed liquid crystal elements according to claim 1 or 2, comprising a compound represented by the formula: Formula (IV-a)

Wherein R ⁵ represents an alkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, and one or more CH ₂ groups present in the alkyl group or alkenyl group are , As oxygen atoms are not directly bonded to each other, may be substituted with oxygen atoms,
A ⁶ , A ⁷ and A ⁸ each independently represents a 1,4-phenylene group, a 1,4-cyclohexylene group or an indan-2,5-diyl group, and the 1,4-phenylene group, indan- The 2,5-diyl group can be unsubstituted or have one or more fluorine, chlorine, methyl, trifluoromethyl or trifluoromethoxy groups as substituents;
Z ⁷ and Z ⁸ each independently represent a single bond, —CH ₂ CH ₂ — or —CF ₂ O—, —COO—,
X ¹³ represents a fluorine atom, a chlorine atom, a trifluoromethyl group or a trifluoromethoxy group, a CF ₂ H group, an isocyanate group,
n ⁴ represents 0, 1 or 2. However, when n ⁴ = 2, a plurality of A ⁶ and Z ⁷ may be the same or different. )
A composition for a polymer-dispersed liquid crystal device according to claim 1, 2 or 3, comprising a compound represented by the formula: The composition for a polymer-dispersed liquid crystal element according to claim 4, comprising a compound represented by general formula (III-a) and general formula (IV-a). 6. The polymer dispersed liquid crystal according to claim 1, wherein at least one or more and four or less of X ⁵² to X ^{57 in} the general formula (Ic) are fluorine atoms or methyl groups. Device composition. The total content of the compound represented by the group represented by the general formula (Ia) and the general formula (Ib) and the compound represented by the general formula (Ic) is 59 to 89% by mass, represented by the general formula (II-b). The composition for a polymer-dispersed liquid crystal device according to claim 1 or 2, wherein the content of the compound to be produced is 10 to 40% by mass and the content of the polymerization initiator is 0.1 to 2% by mass. An active drive polymer dispersion type liquid crystal display device using the composition for polymer dispersion type liquid crystal display device according to claim 1. 8. At least one having an electrode layer has two transparent substrates and a light control layer supported between the substrates, and the light control layer irradiates the composition according to claim 1 with ultraviolet rays. The obtained active drive polymer dispersed liquid crystal display element. 10. The polymer dispersed liquid crystal display element according to claim 9, wherein the light control layer is formed by forming a three-dimensional network structure of a transparent polymer substance in a continuous layer of liquid crystal.