JP5055725B2 - Polymer-dispersed liquid crystal display element composition and polymer-dispersed liquid crystal display element - Google Patents

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.

The polymer-dispersed liquid crystal display element does not require a polarizing plate, so it has the advantage that a bright display can be realized compared to a TN, STN, IPS or VA mode liquid crystal display element using a conventional polarizing plate. Since various optical films for compensating the angle are not required, the structure of the element is simple, so that it is applied to optical shutter applications such as light control glass as shown in Non-Patent Document 1, and segment display applications such as watches. Yes. 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, since a monofunctional acrylate having a molecular weight of 250 or less is used for the prepolymer, 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 Had changing problems.

  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., a practical lower limit temperature at which a low voltage is possible is about 0 ° C.

  As described above, in the polymer dispersion type liquid crystal display element, it is difficult to lower the driving voltage because the driving voltage increases in a low temperature region, and in an active driving application, it can be driven with a voltage lower than the withstand voltage of the TFT to be used. Therefore, there has been a demand for a composition that can reduce temperature dependency and a device that has low temperature dependency. Furthermore, when used for a display medium such as a paper-like display, a liquid crystal device having high whiteness is desired.

  Patent Document 7 discloses the following liquid crystal device as a light-scattering liquid crystal device having improved temperature characteristics and high whiteness in a polymer dispersed liquid crystal element. (1) Contains a polymerizable compound that forms a polymer matrix whose driving voltage decreases with increasing temperature, (2) A polymerizable compound that forms a polymer matrix whose driving voltage increases with increasing temperature, and (3) a liquid crystal composition A liquid crystal device having a light control layer made of a polymer of a polymerizable composition. Specifically, the polymerizable compound as in (1) is a monofunctional (meth) acrylate having a branched alkyl group such as 2-octyldecyl acrylate or 2-heptylnonyl acrylate, and polymerized as in (2). Specifically, the monofunctional (meth) acrylate having a straight-chain alkyl group having 7 to 12 carbon atoms is used as the functional compound, and by combining these, the alkyl side chain on the surface of the polymer matrix in contact with the liquid crystal is used. The density, length, etc. can be controlled, and the affinity between the polymer matrix surface and the liquid crystal can be adjusted. By this method, a liquid crystal composition having a dielectric anisotropy of about 7 to 9 is used, the whiteness is high, and a driving voltage of about 4 to 10 Vrms is achieved at a cell thickness of 11 μm in a temperature range of 15 to 40 ° C. ing. However, since the monofunctional (meth) acrylate has a low gelation rate, unreacted (meth) acrylate remains in the light control layer, and the obtained liquid crystal device is deteriorated by light, heat, etc. However, there is a problem that the drive voltage changes.

  On the other hand, Patent Document 8 discloses a polymer matrix comprising a polymer of a side-chain polyfunctional (meth) acrylate having a linear or branched alkyl group having 4 to 20 carbon atoms in one molecule, and a liquid crystal composition. A liquid crystal device having a light control layer made of is disclosed. A polyfunctional (meth) acrylate having a higher gelation ratio than that of a monofunctional (meth) acrylate is used. Specifically, the dielectric anisotropy is 27.8 and a highly polar cyano liquid crystal composition is used. A liquid crystal device using only a polyfunctional (meth) acrylate having a long-chain linear alkyl group, and changing the distance between the side chains of the alkyl group at a cell thickness of 11 μm in the range of 0 to 50 ° C. About 7 Vrms was achieved. However, when a light-scattering liquid crystal device is used by driving a TFT, the cyano liquid crystal composition has a low liquid crystal resistance and cannot retain an electric charge, thereby making it impossible to display an image.

Patent Document 9 discloses a polymer of a polyfunctional (meth) acrylate having both a linear alkyl group having 4 to 25 carbon atoms and a branched alkyl group having 4 to 26 carbon atoms as side chains in one molecule. A liquid crystal device having a light control layer comprising a polymer matrix comprising the above and a liquid crystal composition is disclosed. Since both linear alkyl groups and branched alkyl groups can be incorporated into the polymer matrix in a certain range, a driving voltage of 5 Vrms can be achieved by using a liquid crystal composition having a dielectric anisotropy of 29.6. . In addition, since the monomer hardly remains, deterioration due to light, heat, or the like can be prevented.
However, since the ratio of linear alkyl groups to branched alkyl groups that can be incorporated into the molecule is limited, the ratio of linear alkyl groups to branched alkyl groups that can be incorporated into the polymer matrix is limited, and there is a limit to the adjustment of temperature change of driving voltage. It was. In addition, the production cost is high because there are many synthesis steps of polyfunctional (meth) acrylate having both a linear alkyl group having 4 to 25 carbon atoms and a branched alkyl group having 4 to 26 carbon atoms as side chains. There were drawbacks.

  In Patent Document 10, a polyfunctional (meth) acrylate having a linear alkyl group on the side chain and a polyfunctional (meth) acrylate having a branched alkyl group on the side chain are mixed to adjust the mixing ratio of the two acrylates. Thus, a technique for improving temperature characteristics is disclosed. It has been shown that low voltage driving with a cell thickness of 11 μm and a driving voltage of 6 Vrms or less is possible even when using a fluorine-based liquid crystal compound having a low dielectric anisotropy and low polarity capable of TFT driving. However, in order to increase the whiteness and obtain white like paper with polymer dispersed liquid crystal, it is necessary to increase the cell thickness to 30 μm or more. The development of a good liquid crystal device has been desired.

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) JP-A-9-329781 JP-A-11-29527 JP 2002-293828 A Japanese Patent Laid-Open No. 2004-2771 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)

  The problem to be solved by the present invention is that amorphous silicon having a cell thickness of 30 μm or more and 20 V or less in a wide temperature range from 0 ° C. to 60 ° C. using a low-polarity fluorine-based liquid crystal composition having a low dielectric anisotropy. An object of the present invention is to provide a light-scattering liquid crystal display element having a light control layer having a high whiteness composed of a polymer matrix and a liquid crystal composition, which can be driven by a TFT and does not change with time.

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,
A polymer-dispersed liquid crystal display element composition is provided, and a polymer-dispersed liquid crystal display element using the composition as a constituent member is also provided.

  The composition for a polymer dispersed liquid crystal display element and the polymer dispersed liquid crystal display element of the present invention can be driven at a low voltage of 0.4 V / μm or less in a temperature range of 0 ° C. to 60 ° C. and reflected. A liquid crystal display element that can be applied to electronic paper having a rate of 30% or more, and has a high voltage holding ratio. Therefore, the composition for a polymer dispersion type liquid crystal display element that can be suitably used in an active drive system and a polymer dispersion Type liquid crystal display elements can be provided.

  An example of the present invention will be described below.

  The composition for a polymer-dispersed liquid crystal display element of the present invention is a transparent polymer in which a radical polymerizable compound contained therein is polymerized by active energy rays such as heat or ultraviolet rays, thereby causing phase separation from the liquid crystal composition. Used to obtain a polymer-dispersed liquid crystal display device comprising a conductive polymer material and a liquid crystal composition.

  As described above, the polymer dispersed liquid crystal display element formed in this way tends to have a remarkable deterioration in display characteristics at low temperatures. In general, the degree is much larger than when a liquid crystal composition, which is one of the constituent elements of a polymer-dispersed liquid crystal display element, is evaluated alone. That is, even when the same liquid crystal composition is used, a polymer-dispersed liquid crystal display element combined with a transparent polymer substance when operated in a display system such as twisted nematic without a transparent polymer substance As a result, the latter low temperature characteristic is overwhelmingly worse. This is because the interaction between the transparent polymer substance and the liquid crystal compound changes greatly at low temperatures.

  For example, Japanese Patent Application Laid-Open No. 6-222320 discloses the relationship of the following formula as a description regarding the driving voltage of a polymer dispersion type liquid crystal display element.

(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 material 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, and the liquid crystal composition. It is determined by the anchoring energy between transparent polymer materials. The 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 substance. Therefore, the factors that increase the drive 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. Among these factors, the anchoring energy between the liquid crystal composition and the transparent polymer substance is a factor specific to the polymer dispersion type liquid crystal display element. Therefore, in order to reduce the temperature dependence of the driving voltage in the polymer dispersed liquid crystal display element and maintain a low driving voltage even at a low temperature, the anchoring energy between the liquid crystal composition and the transparent polymer substance at a low temperature is set. It is necessary to control it to a level close to room temperature.

  Conventionally, the reason why the anchoring energy between the liquid crystal composition and the transparent polymer material is greatly different between room temperature and low temperature is that the molecular chain motion of the polymer material is greatly different depending on the temperature. That is, the polymer chain actively moves at room temperature, and its mobility is great. In particular, since the mobility of the alkyl side chain is large, liquid crystal molecules are prevented from approaching the polymer chain by the excluded volume effect, so that the anchoring energy between them is kept small. On the other hand, when the mobility of the polymer chain is lowered and the excluded volume effect is weakened at a low temperature, the liquid crystal molecules easily approach the polymer chain, and as a result, the anchoring energy between them increases. Thus, a large difference occurs in the anchoring energy between the liquid crystal composition and the transparent polymer material at room temperature and low temperature. The above is a description of the mechanism by which the temperature dependence of the drive voltage occurs.

  Therefore, in order to improve the display characteristics at low temperatures in polymer dispersed liquid crystal display elements, the excluded volume effect is maintained even at low temperatures to suppress the rapid increase in anchoring energy between the liquid crystal composition and the transparent polymer substance. In addition, the inventors of the present application have intensively studied a method capable of driving at a low voltage with an electric field strength of 0.3 V / μm to 0.4 V / μm at room temperature, and as a result, have found the following formulation.

  Room temperature (20-25 ° C) when using straight chain alkyl side chain polymers to increase the density of the side chain sites by shortening the distance between crosslink points in the transparent polymer material to increase the excluded volume effect The driving voltage is low at the above temperature with high molecular mobility. However, in this case, if the temperature drops below room temperature, the excluded volume effect weakens as the molecular mobility decreases, and the liquid crystal molecules approach the linear alkyl side chain so that the liquid crystal molecules are aligned, and the liquid crystal molecules approach the polymer interface. On the other hand, the orientation changes from parallel to perpendicular, and the driving voltage increases due to the anchoring force from the side chain. Therefore, by introducing a branched alkyl side chain into a part of the polymer chain, liquid crystal molecules are difficult to enter between the side chain sites due to the steric hindrance of the branched side chain, and the molecular mobility is somewhat lowered. However, since the excluded volume effect is sustained, an increase in driving voltage at a low temperature below room temperature is suppressed, and the temperature characteristics are improved.

As a result of examining specific measures, the following points became clear.
1) The polymer between the side chain sites is a straight chain alkyl group having 2 to 18 carbon atoms in order to increase the excluded volume effect so that the driving voltage is low at room temperature or higher and the driving voltage is 0.4 V / μm or lower. The main chain length distance is shortened so as to correspond to 10 or less carbon atoms.
2) In order to suppress lowering of the excluded volume effect at low temperature, the side chain site is a branched alkyl group having 4 to 36 carbon atoms, and the polymer main chain length distance between the side chain sites is 10 to 25 carbon atoms. Corresponding range Based on the above prescription, in order to obtain a polymer-dispersed liquid crystal display element composition that can be used for electronic paper applications and the like, it is necessary to increase the whiteness and make the reflectance of the display element at least 30% or more. is there. For this purpose, when the birefringence (Δn) of the liquid crystal composition is 0.2 or more, the cell thickness is at least 30 μm or more, and the TFT is driven by an electric field, the driving voltage is at least 0.4 V / μm or less. It needs to be possible. As a result of intensive studies to satisfy this problem, the following results were found.

The compounds represented by the general formula (Ia), the general formula (Ib), and the general formula (Ic) are compounds that form a liquid crystal composition in the light control layer formed in the polymer dispersion type liquid crystal display element. 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 is excellent in heat resistance and light resistance. In particular, in order to drive with an active element, it is indispensable to have a high specific resistance value and a high dielectric anisotropy. Also, due to the problem of withstand voltage of the active device, the anchoring energy is small between the transparent polymer substance and the liquid crystal composition, and the device can be driven at a low voltage of 0.4 V / μm or less in the operating temperature range of the device. What is possible 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. 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)

(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-33) 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, )

(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 represents a single bond, —C≡C—, —COO— or —CH ₂ CH ₂ —,
n ³ represents 0, 1 or 2. However, when n ³ = 2, each A ³ and each Z ⁵ do not have to be the same. )
Or general 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 represents a 1,4-phenylene group, a 1,4-cyclohexylene group or a 1,3-dioxane-2,5-diyl group, and the 1,4-phenylene group is unsubstituted or substituted. As one or more fluorine atoms, chlorine atoms, methyl groups or trifluoromethyl groups or trifluoromethoxy groups,
A ⁷ and A ⁸ are each independently 1,4-phenylene group, 1,4-cyclohexylene group, decahydronaphthalene-2,6-diyl group, 1,2,3,4-tetrahydronaphthalene-2,6 -Diyl group, 2,6-naphthylene group, or indan-2,5-diyl group, the 1,4-phenylene group, 1,2,3,4-tetrahydronaphthalene-2,6-diyl group, 2,6-naphthylene group and indan-2,5-diyl group are unsubstituted or have one or more fluorine, chlorine, methyl, trifluoromethyl or trifluoromethoxy groups as substituents Can have
Z ⁷ and Z ⁸ each independently represent a single bond, —C≡C—, —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, each A ⁶ and each Z ⁷ do not have to be the same. )
It is also preferable to contain the compound represented by these.
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.

  Next, the compounds represented by formulas (II-a) and (II-b) which are prepolymers will be described in detail.

As a preferred structure of the compound represented by the general formula (II-a), both A ¹ and A ⁹ are preferably hydrogen atoms. Although the effect of the present invention is exhibited even in a compound in which these substituents are methyl groups, the compound in which the substituent is a hydrogen atom is advantageous in that the polymerization rate becomes faster. A ² and A ⁸ are preferably each independently a single bond or an alkylene group having 1 to 3 carbon atoms. When the distance between two polymerizable functional groups is the same, the longer A ² and A ⁸ are, the shorter the length of A ⁵ is. The compound represented by the general formula (II-a) is that the distance between polymerizable functional groups (distance between crosslinking points) is short, but if this distance is too short, the glass transition temperature of the polymer is extremely low. The distance between polymerizable functional groups has a lower limit because the molecular mobility at low temperatures becomes worse and the low temperature characteristics are adversely affected. On the other hand, the distance between the two side chains of A ³ and A ⁶ also affects the low temperature characteristics. That is, if the distance between A ³ and A ⁶ is short, side chains A ³ and A ⁶ will interfere with each other, resulting in a decrease in mobility. Therefore, in the compound represented by the general formula (II-a), the distance between the polymerizable functional groups is determined by the sum of A ² , A ⁸ and A ⁵ , but the side chain sites are equally spaced in the copolymer. preferably better to, in particular, ^{A 5} is preferably 9-12 carbon atoms.

The relationship between the lengths of the side chains A ³ and A ⁴ or A ⁶ and A ⁷ is as follows. In these substituents, it is preferable that A ³ ≧ A ⁴ and A ⁶ ≧ A ⁷ are satisfied. When this relationship holds, the longer side chain A ³ and A ⁶ are each independently the number of straight-chain carbon atoms that may be substituted with an oxygen atom, —CO—, —COO—, or —OCO—. The alkyl group is preferably an alkyl group having 2 to 18 carbon atoms, more preferably an alkyl group having 3 to 14 carbon atoms which may be substituted with an oxygen atom, —CO—, —COO—, or —OCO—. Since the side chain has higher mobility than the main chain, its presence contributes to improvement of the mobility of the polymer chain at low temperature, but as mentioned above, spatial interference occurs between the two side chains. On the contrary, motility decreases. In order to prevent such spatial interference between side chains, it is effective to increase the distance between the side chains and to shorten the side chain length within a necessary range. A ⁴ and A ⁷ are each independently preferably a hydrogen atom and an alkyl group having 1 to 5 carbon atoms, particularly preferably an alkyl group having 2 to 4 carbon atoms, and 2 carbon atoms. Most preferred is an alkyl group. For the Oyobi A ⁷ The A ⁴ also, its is too long length is not preferred to induce spatial interference between side chains. On the other hand, when A ⁴ and A ⁷ are alkyl chains having a short length, they can be side chains having high mobility and have a function of inhibiting the proximity of adjacent main chains. It is conceivable and effective in improving the display characteristics in the low temperature region of the polymer dispersed liquid crystal display element.

A ⁵ located between two side chains, from means to widen the distance between side chains, from the meaning of spreading the distance between crosslinking points lower the glass transition temperature of the polymer, preferably longer. However to come formula compatibility with the liquid crystal composition the molecular weight of (II-a) a compound represented by the too large decreases when A ⁵ is too long, and the polymerization rate slows down too phase separation The length is naturally set to an upper limit because of adverse effects on the length. Also, when A ⁵ is too long it occurs problems such as the drive voltage strongly influenced in terms of bulky from polymer chains anchoring force increases. From this background, A ⁵ may be substituted with an oxygen atom, —CO—, —COO—, or —OCO—, and may have a methyl group or an ethyl group as a branched structure. The number of carbon atoms that may be substituted with an oxygen atom, —CO—, —COO—, or —OCO—, and may have a methyl group or an ethyl group as a branched structure. 9 to 14 alkylene groups are more preferred. Furthermore, most preferably, it may be substituted with an oxygen atom, -CO-, -COO- or -OCO-, and when having a methyl group or an ethyl group as a branched structure, an alkylene having 10 to 16 carbon atoms It is a group.

  About the compound represented by general formula (II-b), general formula (II-b) is shown below as a specific example of a preferable structure.

As a preferable structure of the compound represented by the general formula (II-b), it is preferable that both A ¹⁰ and A ¹⁸ are hydrogen atoms. Although the effect of the present invention is exhibited even in a compound in which these substituents are methyl groups, the compound in which the substituent is a hydrogen atom is advantageous in that the polymerization rate becomes faster. (Wherein A ¹¹ and A ¹⁷ are a single bond or an alkylene group having 1 to 3 carbon atoms, A ¹² and A ¹⁵ each independently represents an alkyl group having 4 to 36 carbon atoms, Specifically, A ¹² and A ¹⁵ are each a 2-ethylhexyl group, an isooctyl group, a 2-n-heptylundecyl group, or a 3,3,5-trimethyl-1-hexyl group. Group, 2-dodecyltetradecyl group, 3-nonyldodecyl group, 3-heptyldecyl group, (2-ethylhexyl) ethoxyethyl group, 2-n-heptylundecyloxyethyl group, 4-butyl-3-propylphenyl group, Examples thereof include tertiary butylphenyl group, polybutylene glycol group, etc. Among them, branching of 6 to 25 carbon atoms such as isooctyl group, 2-n-heptylundecyl group, etc. In addition, one or two or more methylene groups present in the alkyl group are each independently an oxygen atom, —CO—, —COO— or a group in which the oxygen atoms are not directly bonded to each other. A ¹³ and A ¹⁶ each independently represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and one or two present in the alkyl group may be substituted with —OCO—. The above methylene groups may be independently substituted with oxygen atoms, —CO—, —COO—, or —OCO— as those in which the oxygen atoms are not directly bonded to each other, and A ¹⁴ has 18 to 35 carbon atoms. Represents an alkylene group, and one or more methylene groups present in the alkylene group are each independently an oxygen atom, —CO—, —CO, as oxygen atoms are not directly bonded to each other. - or may be substituted with -OCO-, may be substituted with one or two or more hydrogen atoms are each independently a methyl group or an ethyl group present in the alkylene group).
The compound represented by the general formula (II-a) is described in Tetrahedoron Letters, Vol. 30, pp 4985, Tetrahedron Letters, Vol. 23, No. 6, pp 681-684, and Journal of Polymer Science: Part A: Polymer Chemistry, Vol. 34, pp217-225 and the like.

For example, in the general formula (II-a), a compound in which A ⁴ and A ⁷ are hydrogen is a polymerizable compound such as a compound having a plurality of epoxy groups and acrylic acid or methacrylic acid having active hydrogen capable of reacting with the epoxy group. It can be obtained by reacting with a compound to synthesize a polymerizable compound having a hydroxyl group and then reacting with a saturated fatty acid.

  Furthermore, by reacting a compound having a plurality of epoxy groups with a saturated fatty acid, synthesizing a compound having a hydroxyl group, and then reacting with a polymerizable compound such as an acrylate chloride having a group capable of reacting with a hydroxyl group. Obtainable.

When the radical polymerizable compound is, for example, A ⁴ and A ^{7 in} the general formula (II-a) are alkyl groups, and A ² and A ⁸ are methylene groups having 1 carbon atom, an oxetane group is selected. A method of reacting a compound having a plurality of compounds with a fatty acid chloride or a fatty acid capable of reacting with an oxetane group, and further reacting with a polymerizable compound having active hydrogen such as acrylic acid, a compound having one oxetane group, It can be obtained by a method of reacting a polyvalent fatty acid chloride or a fatty acid capable of reacting with an oxetane group, and further reacting with a polymerizable compound having active hydrogen such as acrylic acid.

Further, when A ² and A ⁸ in the general formula (II-a) are propylene groups having 3 carbon atoms, they can be obtained by using a compound having a plurality of furan groups instead of oxetane groups. Furthermore, when A ² and A ⁸ in the general formula (II-a) are a butylene group having 4 carbon atoms, it can be obtained by using a compound having a plurality of pyran groups instead of an oxetane group. The same applies to the general formula (II-b).

  The compound represented by the general formula (II-a) and the compound represented by the general formula (II-b) are mixed and used as a radical polymerizable composition, and the general formula (Ia), (Ib) ), (Ic) and a liquid crystal composition containing at least one kind of compound. These mixing ratios cannot be determined simply because the optimum values differ depending on the combination used. For this reason, the mixing ratio of the liquid crystal composition and the radical polymerizable composition is changed, and further, the mixing ratio of the compound represented by the general formula (II-a) and the compound represented by the general formula (II-b) It is preferable to determine the optimum mixing ratio by examining the change in display characteristics by changing the value. The mixing ratio of the liquid crystal composition and the radical polymerizable composition is preferably in the range of 65% to 75% of the radical polymerizable composition with respect to the liquid crystal composition, and adjusted so as to obtain the desired display characteristics. To do. Further, when the ratio of the compound represented by the general formula (II-a) is M and the ratio of the compound represented by the general formula (II-b) is N, in many cases, a preferable ratio of M: N is 6: It will be between 4 and 95: 5. More preferably, it is between 8: 2 and 9: 1. Specifically, it is preferable to contain 95% to 60% of the general formula (II-a) and 40% to 5% of the general formula (II-b). In this case, the birefringence ( Δn) is preferably 0.2 or more.

The compound constituting the present invention or the radical polymerizable composition may be subjected to a purification treatment with silica, alumina or the like for the purpose of removing impurities or increasing the 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 for polymerizing the composition for a polymer-dispersed liquid crystal display element of the present invention, 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. 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 comprises two substrates having electrodes, at least one of which is a transparent substrate having a transparent electrode, between the two substrates having an isotropic phase. After sandwiching the composition for the molecular dispersion type liquid crystal display element, the polymerizable compound is polymerized by irradiating with heat or active energy rays, and phase separation from the liquid crystal composition is induced, whereby the liquid crystal composition and It is obtained by forming a light control layer made of a transparent polymer material.

  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. A transparent substrate having a transparent electrode layer can be obtained, for example, by sputtering indium tin oxide (ITO) on a transparent substrate such as a glass plate. Further, it is more preferable to use a transparent substrate with low wavelength dispersion because the light scattering ability of the device of the present invention is increased and the reflectance and contrast are improved. Examples of the low wavelength dispersion transparent substrate include borosilicate glass, a plastic transparent film such as polyethylene terephthalate or polycarbonate, and a transparent substrate coated with a dielectric multilayer film using a 1 / 4λ optical interference condition.

  In addition, a polymer film, an alignment film, and a color filter can be disposed on the substrate as necessary. As the alignment film, for example, a polyimide alignment film, a photo alignment film, or the like can be used. As a method for forming the alignment film, for example, in the case of a polyimide alignment film, the polyimide resin composition is applied on the transparent substrate, thermally cured at a temperature of 180 ° C. or higher, and further rubbed with a cotton cloth or a rayon cloth. be able to. In addition, a polymer film such as a polyimide film that has not been rubbed can also be used.

  The color filter can be prepared by, for example, a pigment dispersion method, a printing method, an electrodeposition method, or a dyeing method. A method for producing a color filter by a pigment dispersion method will be described as an example. A curable coloring composition for a color filter is applied on the transparent substrate, subjected to patterning treatment, and cured by heating or light irradiation. By performing this process for each of the three colors red, green, and blue, a pixel portion for a color filter can be created. In addition, a pixel electrode provided with an active element such as a TFT, a thin film diode, or a metal insulator metal specific resistance element may be provided on the substrate.

  The said board | substrate is made to oppose so that a transparent electrode layer may become an inner side. In that case, you may adjust the space | interval of a board | substrate through a spacer. At this time, it is preferable to adjust so that the thickness of the light control layer obtained may be set to 1-100 micrometers. Among these, 2 to 50 μm is preferable, 2 to 30 μm is more preferable, 2 to 10 μm is further preferable, and 3 to 6 μm is most preferable. Examples of the spacer include glass particles, plastic particles, alumina particles, and a photoresist material. Thereafter, a sealant such as an epoxy thermosetting composition is screen-printed on the substrates with a liquid crystal inlet provided, the substrates are bonded together, and heated to thermally cure the sealant.

  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 use a metal halide lamp, a high-pressure mercury lamp, or an ultra-high pressure mercury lamp to cut off ultraviolet rays of 330 nm or less, and to 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.

  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 10 ° C. is preferable, and the transition point +0.1 to 3 ° C. is more 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, but V90 at a cell thickness of 5 μm is preferably 7.5 v or less, more preferably 6.5 v or less.

  In addition, a light absorption layer, a diffusive reflector, or the like can be disposed on the back side of the liquid crystal device of the present invention, and a reflective polymer dispersed liquid crystal display element with high reflectivity and contrast can be obtained. Color display is possible by arranging light absorbing layers having different light absorption wavelengths such as cyan, magenta, and yellow so as to coincide with the positions of the pixel electrodes divided for each color. Functions such as specular reflection, diffuse reflection, retroreflection, and hologram reflection can also be added.

EXAMPLES Hereinafter, although a synthesis example, a manufacture example, and an Example are given and this invention is further explained in full detail, this invention is not limited to these examples. In the following synthesis examples, production examples, examples and comparative examples, “%” means “% by mass” unless otherwise specified.
(Production and evaluation of polymer-dispersed liquid crystal display elements)
The polymer dispersion type liquid crystal display elements in the examples were produced by the following method.

A light control layer forming material comprising a liquid crystal composition, a radical polymerizable composition, a photopolymerization initiator and a small amount of a polymerization inhibitor was injected into a glass cell with ITO having a cell gap of 30 μm by a vacuum injection method. At this time, the temperature in the vacuum injection apparatus was controlled so that the light control layer forming material was always in a uniform state. The degree of vacuum was set to 2 Pascals. After the injection, the glass cell was taken out, the inlet was sealed with a sealing agent 3026E (manufactured by ThreeBond), and then the temperature was controlled to 1 to 2 ° C. higher than the isotropic-nematic transition point of the light control layer forming material. Through a L-37 (manufactured by Hoya Candeo Optronics Co., Ltd.), a metal halide lamp adjusted so that the irradiation intensity of the sample surface is 40 mW / cm ² is irradiated for 80 seconds to obtain a polymer dispersed liquid crystal display element. It was. This irradiation condition is determined by taking into consideration the characteristic variation and the temporal stability of the produced polymer dispersed liquid crystal display element. As an example, under the conditions of an irradiation intensity of 10 mW and an exposure time of 60 seconds, the driving voltage of the manufactured element tends to vary and the driving voltage of the element changes with time. This is because, when the illuminance and the exposure time are short, the fluctuation of the small exposure condition greatly affects the characteristics of the device. Under this irradiation condition, a non-negligible amount of unpolymerized monomer remains in the polymer dispersed liquid crystal display device. Because.

  Abbreviations and meanings of characteristics of the polymer dispersed liquid crystal display elements shown in the examples are as follows.

In a low temperature environment of 0 to 25 ° C. or a high temperature environment of 60 ° C., an alternating voltage of 60 Hz is applied to the polymer dispersed liquid crystal display element. The applied voltage is increased stepwise from no application to 50 V under the conditions of 0.5 V / step and 3 seconds / step. When the applied voltage reaches 50 V, the applied voltage is lowered to no application at 0.5 V step and 3 seconds / step. The following characteristic values are defined from the relationship between the applied voltage and the light transmittance when this operation is performed.
T0: Light transmittance (%) when no voltage is applied.
T100: Light transmittance (%) when the light transmittance change with increasing applied voltage reaches saturation and the light transmittance stops changing.
T90: Light transmittance (%) defined by T0 + 0.9 × (T100−T0).
V100: Applied voltage (V) at T100.
Vr90: Applied voltage (V) at the transmittance of T90 when the applied voltage to the polymer dispersed liquid crystal display element is increased from no application.
In addition to the above, the following characteristic values are defined.
T100 (Vr90): Transmittance (%) when the light transmittance reaches saturation when the voltage of Vr90 is continuously applied to the polymer dispersion type liquid crystal display element.
T10 (Vr90): Light transmittance (%) defined by T0 + 0.1 × (T100 (Vr90) −T0).
T90 (Vr90): Light transmittance (%) defined by T0 + 0.9 × (T100 (Vr90) −T0).
Voltage holding ratio (VHR): Ideal waveform when there is no voltage drop at a pulse width of 64μsec, a frame period of 200msec, and an applied voltage of 5V, measured using a liquid crystal voltage holding ratio measurement system VHR-A1 (manufactured by Toyo Corporation). And area ratio (%).
Reflectivity: A standard white plate (laboratory, Sophia, USA) was installed at the center of the integrating sphere, and the reflected light intensity on the surface was measured with a luminance meter to determine the reflectivity of 100%. The reflectance was obtained by measuring the intensity of the reflected light on the surface of the integrating sphere.
Example 1
70% of the liquid crystal composition (A), 29.4% of the radical polymerizable composition composed of the radical polymerizable compound M-1 and the bifurcated side chain bifunctional type radical polymerizable compound M-2, a photopolymerization initiator A polymer-dispersed liquid crystal display element composition comprising 0.6% of Irgacure 651 (manufactured by Ciba Specialty Chemicals) was prepared, 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) is -21 to 91 ° C. The mixing ratio of the radically polymerizable compounds M-1 and M-2 was 70:30, 80:20, 85:15, and the polymer dispersion type liquid crystal display elements were at 0 ° C, 10 ° C, 25 ° C, 40 ° C, 60 ° C, respectively. Vr90 at ° C was evaluated. The evaluation results are shown in Table 1. In Table 1, M-1 (%) means the radical polymerizable compound M-1 in the radical polymerizable composition comprising the radical polymerizable compound M-1 and the radical polymerizable compound M-2. It is the numerical value which showed content by the mass%.

  When the compound of general formula (II-b) is mixed with the compound of general formula (II-a) in the present invention, the content of general formula (II-a) decreases and the content of (II-b) increases. As shown in Table 1, the characteristic value of Vr90 is 0 ° C until M-1 (%) is 85%, and the value of 25 ° C is slightly increased and the temperature characteristic is improved slightly. Can be driven at a low voltage of 0.33 V / μm and can be driven by a TFT or the like at 20 V or less even at 0 ° C. If this optimum concentration value is exceeded, the value of 40 ° C. increases conversely and the voltage of 25 ° C. increases. However, TFT drive is possible at a temperature range of 0 to 60 ° C., indicating 20 V or less. That is, at a certain mixing ratio, Vr90 can lower the driving voltage near room temperature, and does not exceed 20 V even at 0 ° C. When M-2 is not added to M-1, as shown by M-1 (%), it shows a high driving voltage of 35 V at 0 ° C. Therefore, the present invention using two types of monomers improves temperature characteristics. It turns out that it is effective. Moreover, the reflectance of the produced cell was 35 to 36% regardless of the mixing ratio of M-1 and M-2, and a cell with high whiteness was obtained. Further, a characteristic capable of TFT driving was obtained with a voltage holding ratio of 97 to 98% regardless of the mixing ratio of M-1 and M-2.

The optimal composition in Example 1 is that the content of the radical polymerizable compound M-1 in the radical polymerizable composition is 80 to 85%, the content of M-2 is 15 to 20%, and the desired characteristics. The characteristics can be adjusted according to the above.
Liquid crystal composition (A)

(Example 2)
70% of the liquid crystal composition (A), 29.4% of the radically polymerizable composition comprising the radically polymerizable compound M-1 and M-3, which is a bifunctional branched-chain bifunctional type radically polymerizable compound, a photopolymerization initiator A polymer-dispersed liquid crystal display element composition comprising 0.6% of Irgacure 651 (manufactured by Ciba Specialty Chemicals) was prepared, and a polymer-dispersed liquid crystal display element was obtained by the method described above. Vr90 at 0 ° C., 10 ° C., 25 ° C., 40 ° C. and 60 ° C. of the polymer dispersed liquid crystal display element was evaluated. The evaluation results are shown in Table-2. In Table 1, M-1 (%) means the radical polymerizable compound M-1 in the radical polymerizable composition comprising the radical polymerizable compound M-1 and the radical polymerizable compound M-3. It is the numerical value which showed content by the mass%. The optimum composition in Example 2 is that the content of the radical polymerizable compound M-1 in the radical polymerizable composition is 90 to 80%, the content of M-3 is 10 to 20%, and the desired characteristics. The characteristics can be adjusted according to the above. Moreover, the reflectance of the produced cell was 35 to 36% regardless of the mixing ratio of M-1 and M-3, and a cell with high whiteness was obtained. Further, a characteristic capable of TFT driving was obtained with a voltage holding ratio of 97 to 98% regardless of the mixing ratio of M-1 and M-2.

(Example 3)
The liquid crystal composition (A) is 70%, and the radical polymerizable compound M-1 of Example 1 is replaced with M-4, and consists of M-4 and M-3 which is a bifurcated monofunctional type radical polymerizable compound. A polymer-dispersed composition for a liquid crystal display device comprising 29.4% of a radical polymerizable composition and 0.6% of a photopolymerization initiator Irgacure 651 (manufactured by Ciba Specialty Chemicals Co., Ltd.) was prepared. A liquid crystal display element was obtained. Vr90 at 0 ° C., 10 ° C., 25 ° C., 40 ° C. and 60 ° C. of the polymer dispersed liquid crystal display element was evaluated. The evaluation results are shown in Table 1. In Table 1, M-4 (%) means the radical polymerizable compound M-4 in the radical polymerizable composition comprising the radical polymerizable compound M-4 and the radical polymerizable compound M-3. It is the numerical value which showed content by the mass%. The optimum composition in Example 3 is that the content of the radical polymerizable compound M-4 in the radical polymerizable composition is 90 to 80%, the content of M-2 is 10 to 20%, and the desired characteristics. The characteristics can be adjusted according to the above. Moreover, the reflectance of the produced cell was 35 to 36% regardless of the mixing ratio of M-3 and M-4, and a cell with high whiteness was obtained. Furthermore, a characteristic capable of TFT driving was obtained with a voltage holding ratio of 97 to 98% regardless of the mixing ratio of M-3 and M-4.

(Comparative Example 1)
A composition for a polymer dispersion type liquid crystal display device comprising 70% of a liquid crystal composition (A), 29.4% of a radical polymerizable compound M-5, 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. Vr90 at 0 ° C., 10 ° C., 25 ° C., 40 ° C. and 60 ° C. of the polymer dispersed liquid crystal display element was evaluated. The evaluation results are shown in Table-3.

(Comparative Example 2)
A composition for a polymer dispersion type liquid crystal display device comprising 70% of a liquid crystal composition (A), 29.4% of a radical polymerizable compound M-6, 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. Vr90 at 0 ° C., 10 ° C., 25 ° C., 40 ° C. and 60 ° C. of the polymer dispersed liquid crystal display element was evaluated. The evaluation results are shown in Table-4.

(Comparative Example 3)
The liquid crystal composition (A) is 70%, the radical polymerizable composition comprising the radical polymerizable compound M-4 and the linear bifunctional type radical polymerizable compound M-6 is 29.4%, the photopolymerization initiator Irgacure 651 A polymer-dispersed liquid crystal display element composition comprising 0.6% (manufactured by Ciba Specialty Chemicals) was prepared, and a polymer-dispersed liquid crystal display element was obtained by the method described above. Vr90 at 0 ° C., 10 ° C., 25 ° C., 40 ° C. and 60 ° C. of the polymer dispersed liquid crystal display element was evaluated. The evaluation results are shown in Table-5. In Table 1, M-4 (%) means the radical polymerizable compound M-1 in the radical polymerizable composition comprising the radical polymerizable compound M-4 and the radical polymerizable compound M-6. It is the numerical value which showed content by the mass%. Even when M-6 is added, the Vr90 at 0 ° C. exceeds 20 V, and the low temperature driving voltage is high.

(Comparative Example 4)
70% of the liquid crystal composition (A), 29.4% of the radical polymerizable composition comprising the radical polymerizable compound M-4 and the linear bifunctional type radical polymerizable compound M-7, photopolymerization initiator Irgacure 651 A polymer-dispersed liquid crystal display element composition comprising 0.6% (manufactured by Ciba Specialty Chemicals) was prepared, and a polymer-dispersed liquid crystal display element was obtained by the method described above. Vr90 at 0 ° C., 10 ° C., 25 ° C., 40 ° C. and 60 ° C. of the polymer dispersed liquid crystal display element was evaluated. The evaluation results are shown in Table-6. In Table 6, M-4 (%) means the radical polymerizable compound M-4 in the radical polymerizable composition comprising the radical polymerizable compound M-4 and the radical polymerizable compound M-7. It is the numerical value which showed content of mass by the mass%. When M-7 is added, there is an increase in Vr90 at 0 ° C., and the driving voltage at a low temperature exceeding 20 V is high.

Claims (4)

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 and A ² 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 or two substituents. It can have the above fluorine atom, chlorine atom, methyl group or trifluoromethyl group or trifluoromethoxy group,
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 ⁶ and X ⁸ to X ¹² each independently represent a hydrogen atom, a fluorine atom, a chlorine atom, a trifluoromethyl group or a trifluoromethoxy group,
Z ¹ and Z ³ each independently represent a single bond or —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. )
Or a compound selected from the group of compounds represented by formula (Ic)

(In the formula, 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 has one or more fluorine atoms, chlorine atoms as substituents, 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 non-bonded group)), a fluorine atom, a chlorine atom, an isocyanate group, a trifluoromethyl group, a trifluoromethoxy group, a difluoromethoxy group or the general formula (Id). Represent,

(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. )
And a compound represented by the general formula (II-a)

(In the formula, A ¹ and A ⁹ each independently represent a hydrogen atom or a methyl group; A ² and A ⁸ each independently represent a single bond or an alkylene group having 1 to 15 carbon atoms; One or more methylene groups present therein may be each independently substituted with an oxygen atom, —CO—, —COO— or —OCO— as those in which oxygen atoms are not directly bonded to each other, One or two or more hydrogen atoms present in the alkylene group may be each independently substituted with a fluorine atom, a methyl group, or an ethyl group, and A ³ and A ⁶ are each independently 2 carbon atoms. To 20 straight chain alkyl groups, and one or more methylene groups present in the alkyl group are each independently an oxygen atom, —CO—, —COO on the assumption that oxygen atoms are not directly bonded to each other. Or may be substituted with -OCO-, A ⁴ and A ⁷ each independently represents an alkyl group having 2 to 4 carbon atoms, or two or more methylene groups present in the alkyl group Are each independently substituted with an oxygen atom, —CO—, —COO— or —OCO— as those in which oxygen atoms are not directly bonded to each other, and one or more of them are present in the alkyl group Each hydrogen atom may be independently substituted with a halogen atom or an alkyl group having 1 to 9 carbon atoms, and A ⁵ represents an alkylene group having 6 to 16 carbon atoms , and one existing in the alkylene group Alternatively, two or more methylene groups may be independently substituted with an oxygen atom, —CO—, —COO—, or —OCO— so that oxygen atoms are not directly bonded to each other.
Containing a compound represented by
Formula (II-b)

(In the formula, A ¹⁰ and A ¹⁸ each independently represent a hydrogen atom or a methyl group; A ¹¹ and A ¹⁷ each independently represent a single bond or an alkylene group having 1 to 15 carbon atoms; One or more methylene groups present therein may be each independently substituted with an oxygen atom, —CO—, —COO— or —OCO— as those in which oxygen atoms are not directly bonded to each other, One or two or more hydrogen atoms present in the alkylene group may be each independently substituted with a fluorine atom, a methyl group, or an ethyl group, and A ¹² and A ¹⁵ each independently have 4 carbon atoms. To 36 branched alkyl groups, and one or more methylene groups present in the alkyl group are each independently an oxygen atom, —CO 2, as oxygen atoms are not directly bonded to each other. May be substituted with -COO- or ^-OCO-, respectively ^{A 13} and ^{A 16} independently represent a hydrogen atom, or an alkyl group having 1 to 10 carbon atoms, existing in the alkyl group 1 One or two or more methylene groups may be independently substituted with an oxygen atom, —CO—, —COO— or —OCO—, as oxygen atoms are not directly bonded to each other, and are present in the alkyl group. 1 or 2 or more hydrogen atoms may be each independently substituted with a halogen atom or an alkyl group having 1 to 9 carbon atoms, A ¹⁴ represents an alkylene group having 9 to 40 carbon atoms, One or two or more methylene groups present in the alkylene group are each independently substituted with an oxygen atom, —CO—, —COO— or —OCO— as if the oxygen atoms were not directly bonded to each other. May be.) Contain at least one kind of the compound represented by the polymer dispersed liquid crystal display element composition characterized.   The composition for a polymer-dispersed liquid crystal display element according to claim 1, wherein the content of the general formula (II-a) is 60 to 95% by weight and the content of the general formula (II-b) is 5 to 40% by weight. object.   By having at least one substrate having at least one electrode layer transparent and a light control layer supported between the substrates, the light control layer irradiates the composition according to claim 1 with ultraviolet rays. Obtained polymer dispersion type liquid crystal display element. 4. The polymer dispersed liquid crystal display element according to claim 3 , 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.