JP3055299B2 - Liquid crystal-polymer composite film and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a novel liquid crystal-polymer composite film and a method for producing the same. More specifically, a liquid crystal that can be widely applied as a display element such as a display, a light control element, a light modulation element, an optical shutter, a memory element, and the like.
The present invention relates to a polymer composite membrane and a method for producing the same.

[0002]

2. Description of the Related Art Low molecular weight liquid crystal materials are most commonly used as display materials for flat panel displays, such as TN type liquid crystal display elements such as clock faces and STN type for portable computers and portable word processors. Widely applied to liquid crystal display devices and the like. These control the transmission / non-transmission (ON / OFF) of light by utilizing the property that the polarization plane of the light passing through the liquid crystal layer changes according to the applied voltage, so that a total of two sheets are provided on both sides of the liquid crystal layer. A polarizing plate is required. In addition, it is indispensable to perform an alignment film treatment for the liquid crystal layer to assume a specific alignment state.

In recent years, a hybrid type liquid crystal display device in which a low molecular weight liquid crystal material is dispersed or encapsulated in a polymer binder has been proposed (US Pat. No. 4,435,435).
No. 047, JP-T-58-501631, JP-T-61-502128, and JP-A-62-2231.
JP, JP-A-64-62615, JP-A-Heisei 1-3
12527, JP-A-2-55787). For example, Japanese Patent Publication No. 58-501631 proposes a film in which nematic liquid crystal droplets encapsulated in polyvinyl alcohol are dispersed. When no voltage is applied, this film scatters light incident on the film because the nematic liquid crystal in the liquid crystal droplets is oriented along the capsule wall surface, while the nematic liquid crystal is applied when voltage is applied. Are aligned in the direction of the electric field, so that light incident on the film is transmitted.
It is said to take two states of transmission. In addition, Tokuyo Sho 61-
JP-A-502128 and JP-A-62-2231 disclose that a mixture of a polymerizable composition such as epoxy and a low-molecular liquid crystal material is irradiated with ultraviolet light or heat to polymerize the polymerizable composition to cause phase separation. A liquid crystal element in which liquid crystal droplets are dispersed and held in a binder has been proposed. Further, Japanese Patent Application Laid-Open No. 2-55787 proposes a liquid crystal element capable of lowering the driving voltage by increasing the ratio of the low-molecular liquid crystal material used in the above-described phase separation method by ultraviolet polymerization. .

[0004] The above-mentioned liquid crystal display element utilizes the property that the scattering state of transmitted light changes when a voltage is applied, and thus the light transmission / reception is reduced.
This controls the scattering (ON / OFF). Therefore, a polarizing plate, which is indispensable for the conventional TN type liquid crystal display element and STN type liquid crystal display element, becomes unnecessary, and a device incorporating such a display element can provide a brighter display. In addition, since an alignment film is not required, steps such as printing, baking, and rubbing of the alignment film are not required, which is advantageous in terms of manufacturing cost.

[0005]

However, in a conventional hybrid display device in which a low-molecular liquid crystal material is held in a polymer binder, the driving voltage required to drive the liquid crystal-polymer composite film is several. 10 ~ 100Vrms
And its use is limited. That is, it cannot be applied to time-division driving, and it is also difficult to apply it to an active matrix display element using a TFT or MIM. Slightly simple dimming element (dimming glass)
It is simply applied as Further, the steepness of the applied voltage-transmittance curve is poor, and there is almost no memory property such as a hysteresis characteristic. Therefore, application to a large-screen display element was practically impossible.

[0006] The present invention has been made in view of the above circumstances. That is, the object of the present invention is applicable not only to a dimming element but also to a display element, a light modulation element, an optical shutter, and a memory element that can be driven at a low voltage of 50 Vrms or less and have sufficient contrast and response time. To provide a liquid crystal-polymer composite film. At the same time, it is an object of the present invention to provide a liquid crystal-polymer composite film which can be applied to a display device having a larger screen by realizing a hysteresis characteristic which has not been achieved conventionally. Another object of the present invention is to provide a method for producing a liquid crystal-polymer composite film having the above-mentioned characteristics.

[0007]

Means for Solving the Problems As a result of intensive studies on the liquid crystal-polymer composite film, the present inventors have focused on the constituent components of the polymer compound and the mixing ratio of the low-molecular liquid crystal to the polymer compound. Having a liquid crystalline side chain component and a non-liquid crystalline component in the molecule as a polymer compound, the molar ratio of the liquid crystalline side chain component to the non-liquid crystalline component and the blending ratio of the low molecular weight liquid crystal to the polymer compound are within predetermined ranges. By setting, it was further found that a liquid crystal-polymer composite film in which the control of liquid crystal droplets was easy was obtained, and the present invention was completed.

That is, the present invention relates to a low-molecular liquid crystal of at least one kind , a monomer having a liquid crystal substituent, and a liquid crystal.
A liquid crystal comprising a polymer having at least one liquid crystalline side chain component and at least one non-liquid crystalline component, each of which is a copolymer with a polymerizable component having no substituent. - made of polymer composite film, the polymer compound in the liquid crystal side chain component and a non-liquid-crystalline component molar ratio 0.1: 100 to 100: 1 and the low molecular liquid crystal and the polymer compound by weight A novel liquid crystal-polymer composite film having a ratio of 1:10 to 50: 1. The present invention also provides a polymerizable monomer having a low molecular weight liquid crystal and a liquid crystal substituent and a polymerizable component having no liquid crystal substituent each having at least one polymerizable monomer.
Preparing a mixture with the seed-containing polymerizable composition, followed by a polymerizable model having a liquid crystalline substituent of the polymerizable composition.
A step of co-polymerizing the polymerizable component having no liquid crystal substituent and a monomer having a liquid crystal substituent and having a total number of moles of the polymerizable monomer having a liquid crystal substituent in the polymerizable composition. 0.1: 100 to 1
00: 1 and the weight ratio of the low-molecular liquid crystal to the polymerizable composition in the mixture is 1:10 to 50: 1.

Hereinafter, the present invention will be described in detail. The liquid crystal-polymer composite film of the present invention exhibits its function when the low-molecular liquid crystal and the high-molecular compound are phase-separated from each other. The form of the phase separation may be such that each droplet is dispersed and held, or a plurality of liquid crystal droplets may be aggregated. The shape of the liquid crystal droplet may be spherical or polyhedral as in the case where a polymer compound forms a wall on a thin film. Further, the liquid crystal may form a continuous phase. The microstructure of the liquid crystal-polymer composite film can be variously changed depending on the types (thermodynamic properties and chemical properties) of the low-molecular liquid crystal and the polymer compound to be used, the mixing ratio, and the like. The following forms are illustrated by way of example. FIG. 1A is an example in which a high molecular compound 2 is used in excess of a low molecular liquid crystal 1,
The liquid crystal-polymer composite film 3 in which the low-molecular liquid crystal 1 is dispersed in the polymer compound 2 in a microdroplet shape is illustrated. FIG. 1B is an example in which low-molecular liquid crystal 1 and high-molecular compound 2 are used in substantially equal amounts, and illustrates a sponge-like liquid crystal-polymer composite film 3. FIG. 1C is an example in which the low-molecular liquid crystal 1 is used in excess of the high-molecular compound 2, and illustrates a liquid crystal-polymer composite film 3 in which the high-molecular compound 2 is distributed in a fibrous form in the low-molecular liquid crystal 1. Is shown.

[0010] The low-molecular liquid crystal constituting the liquid crystal-polymer composite film includes various liquid crystals used as general display materials or electric field driven display materials such as nematic liquid crystal, cholesteric liquid crystal, smectic liquid crystal and ferroelectric liquid crystal. Can be used. Specifically, biphenyl, phenylbenzoate, cyclohexylbenzene, azoxybenzene, azobenzene, azomethine, terphenyl, biphenylbenzoate,
Cyclohexylbiphenyl, phenylpyrimidine,
Various liquid crystal compounds such as cyclohexylpyrimidine and cholesterol are exemplified. These low-molecular liquid crystals do not need to have a single composition like liquid crystal materials generally used, and may be composed of a plurality of components. For the purpose of displaying by an electric field, it is preferable to use a liquid crystal compound having a positive dielectric anisotropy among the above. Some liquid crystals change the dielectric anisotropy from positive to negative when the frequency of the applied voltage exceeds a certain value (crossover frequency).
It goes without saying that the present invention can be applied to frequency driving.

The polymer compound, which is the other component of the liquid crystal-polymer composite film, contains at least one liquid crystal side chain component and at least one non-liquid crystal component in the molecule. A side chain type polymer liquid crystal of a homopolymer having a liquid crystal component in a polymer compound is known as an electro-optic material,
The polymer compound in the present invention includes a polymerizable monomer having a polymerizable liquid crystal substituent (hereinafter, referred to as a liquid crystal monomer) and a polymerizable component having no liquid crystal substituent (hereinafter, a non-liquid crystal polymerizable component). And a polymerizable composition containing at least one of them in a predetermined molar ratio. Also, but it may also be a polymer compound bonded by an addition reaction liquid crystalline side chains and non-liquid crystalline side chain.

The above-mentioned liquid crystal monomer is a compound in which a liquid crystal compound is bonded to a vinyl group, an acryl group, a methacryl group or the like via an appropriate alkyl spacer. These are described, for example, in Makromol. Chem. Vol. 1
8, p651 (1982). Specific examples thereof include, for example, biphenyl, phenylbenzoate, cyclohexylbenzene, azoxybenzene, azobenzene, azomethine, terphenyl, biphenylbenzoate, cyclohexylbiphenyl, phenylpyrimidine, and cyclohexylpyrimidine. And cholesterol-based liquid crystal compounds are bonded to a vinyl group, an acryl group, a methacryl group or the like via an appropriate alkyl spacer. These liquid crystal monomers need not be a single compound, and may be used in combination of two or more.

Representative liquid crystalline monomers are shown below. In the following formula, R represents a hydrogen atom or a methyl group, and Z represents a halogen atom, a cyano group, an alkoxy group or a halogenated alkyl group. Also, m is 2 to 30
And n is an integer of 1 to 20.

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As the non-liquid crystalline polymerizable component which is the other component contained in the polymer compound, a monomer or oligomer which does not exhibit liquid crystallinity and can be copolymerized with the above-mentioned liquid crystalline monomer can be used. . Specific examples thereof include, in the case of polymerization, acrylic acid, methacrylic acid, alkyl acrylate, alkyl methacrylate, acrylamide, methacrylamide and their derivatives, styrene and its derivatives, acrylonitrile, methacrylonitrile, ethylene and its Derivatives, vinyl chloride, vinylidene chloride, butadiene, isoprene, chloroprene,
Not only monofunctional monomers such as vinylpyrrolidone, polyethylene glycol monoacrylate having a molecular weight of 500 to 20,000 and its monomethacrylate, but also polyols such as ethylene glycol, propylene glycol, 1,3-propanediol, glycerin, pentaerythritol, and polyethylene glycol Polyfunctional monomers having two or more polymerizable groups in a molecule, such as an ester in which a plurality of molecules of acrylic acid or methacrylic acid are bonded, divinylbenzene, and divinyl adipate are exemplified. In the case of the addition reaction, compounds having a reactive unsaturated bond at the terminal, for example, 1-propene, 1-butene, 1-hexene and the like can be mentioned. These non-liquid crystalline polymerizable components may be oligomers in which some monomers are polymerized,
The compound need not be a single compound, and two or more compounds can be used in combination.

In the synthesis of the polymer compound of the present invention, in the case of polymerization, ordinary radical polymerization or ionic polymerization is possible, and a polymerizable composition containing a liquid crystal monomer and a non-liquid crystal polymerizable component is polymerized. It is carried out by copolymerization by heating or light irradiation in the presence or absence of an initiator.
This synthesis may be performed simultaneously with the production of the liquid crystal-polymer composite film described later. With this polymerization, the liquid crystalline monomer and the non-liquid crystalline polymerizable component become a liquid crystalline side chain component and a non-liquid crystalline component, respectively. In addition, the addition reaction is carried out by adding the two components to a reactive prepolymer represented by polyhydromethylsilicone using a platinum catalyst or the like. Thermal polymerization represented by an azobis initiator such as 2,2'-azobisisobutyronitrile and 1,1'-azobis-1-cyclohexanenitrile is used as a polymerization initiator added at the time of the radical polymerization. Initiators or photoinitiators such as 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, and the like. Any one used can be appropriately selected and used according to the polymerization method.

The molar ratio of the liquid crystalline side chain component to the non-liquid crystalline component in the synthesized polymer compound is 0.1: 100 to 10:
It must be set in the range of 0: 1. In order to synthesize a polymer compound in which the molar ratio of both components is within the above range, the composition ratio of the liquid crystalline monomer and the non-liquid crystalline polymerizable component is adjusted to the above range in the ratio of the total mole number to the polymerizable compound. The composition may be copolymerized. When the liquid crystal side chain component is larger than the above range, the polymer compound becomes compatible with the low molecular weight liquid crystal, and the properties as a display material are not expected. Function is lost. The preferred range is 0.1: 100 to 5: 1.

Next, a method for producing the liquid crystal-polymer composite film of the present invention will be described. As a particularly desirable method, a low-molecular liquid crystal and a polymerizable composition are preferably mixed with the polymerization initiator to prepare a uniform solution, and this solution is used in advance to prepare two counter electrode plates having an optimum gap. after sealed in a cell comprising a liquid crystalline substituent of the polymerizable composition by heat or light, etc.
Having a polymerizable monomer and having no liquid crystalline substituent
A method of producing a liquid crystal-polymer composite film by copolymerizing a polymerizable component is exemplified . In addition, a mixed solution in which a low-molecular liquid crystal and a high-molecular compound are dissolved in a common solvent is prepared, and this solution is applied to a substrate such as a transparent electrode, dried, and then the electrode substrate is attached. Thereby, the composite film can be produced.

The content of the low-molecular liquid crystal in the liquid crystal-polymer composite film can be variously changed depending on the desired performance. The compounding ratio of the low-molecular liquid crystal and the high-molecular compound is 1:10 to 50 by weight. : 1 must be set. If the amount of the low-molecular liquid crystal is larger than this range, it is difficult to produce a composite film having self-holding properties and mechanical strength, and if the amount is small, the performance as a target display material cannot be obtained. The preferred range is from 1: 5 to 20: 1, particularly preferably from 1: 1 to 9: 1.

The liquid crystal-polymer composite film of the present invention can be used as a display material or a memory material even if it is composed of only two components, a low-molecular liquid crystal and a high-molecular compound. For the purpose of improving the durability, various compounds can be added. For example, various dichroic dyes such as anthraquinone type, styryl type, azomethine type and azo type can be used for the purpose of improving the contrast. In that case, it is preferable that the dichroic dye is basically compatible with the liquid crystal component in the composite film and is incompatible with the polymer compound. In addition, antioxidants, ultraviolet absorbers, various plasticizers, and the like are also preferably used from the viewpoint of improving stability and durability.

As a form of the device of the liquid crystal-polymer composite film, as shown in FIG. 2, a structure sandwiched between two electrode plates 4 and 5 is preferable as in a normal liquid crystal element. FIG. 2 shows that a voltage is applied to the electrode plates 4 and 5 from the power
3 shows a state in which the composite film 3 is oriented in the electric field direction in the composite film 3. When this voltage is applied, light incident on the composite film 3 is transmitted. As the electrode plate, for example, IT
O-treated glass substrate, plastic film, NES
A transparent electrode plate such as an A glass substrate is preferably used. As described above, the device is manufactured by encapsulating a mixture of a low-molecular liquid crystal and a polymerizable composition in a cell and then polymerizing the polymerizable composition, or forming a composite film on one electrode plate. After that, a method of bonding the other electrode plate is applicable. At this time, it is also preferable to use an appropriate spacer material or to provide a protective layer or an adhesive layer between the electrode plate and the composite film, as in the prior art.

[0021]

The operation of the liquid crystal-polymer composite film of the present invention will be described below with reference to FIG. 3 showing the principle of operation of the composite film. When no voltage is applied to the electrode plates 4 and 5, the low-molecular liquid crystal 1 is dispersed and held in the composite film 3 in a phase-separated state, and the orientation vector of the liquid crystal molecules 1a is Figure 3
As shown in (A), the light is turbid due to scattering of incident light. When no voltage is applied as described above, the liquid crystal side chain component 2a in the polymer compound 2 has a high affinity for the liquid crystal molecule 1a. In a dissolved state, just like a low-molecular liquid crystal 1
Is in a state of being surrounded by the interface of the liquid crystal side chain component 2a. On the other hand, when a voltage is applied to voltages 4 and 5 to generate an electric field, the liquid crystal molecules 1a in the composite film 3 change as shown in FIG.
As shown in FIG. 3, since the light is oriented in the direction of the electric field, the incident light is transmitted and the state changes from a cloudy state to a transparent state. When a voltage is applied in this manner, the liquid crystal side chain component 2a at the interface also
Since the liquid crystal molecules are aligned in the same direction as the liquid crystal molecules 1a and anchoring at the interface is reduced, it is considered that the liquid crystal molecules 1a operate at a low applied voltage.

In the liquid crystal-polymer composite film of the present invention, the polymer compound has a liquid crystal side chain component, and this liquid crystal side chain component has a strong affinity for the low molecular liquid crystal in the composite film. Therefore, it is estimated that they are arranged at the interface between the low-molecular liquid crystal phase and the high-molecular compound phase. As a result, it is considered that the force for attaching the low-molecular liquid crystal molecules to the polymer compound interface was reduced, and the driving at a lower voltage became possible. Also, when using a liquid crystalline side chain component that is oriented at a higher voltage than a low molecular liquid crystal,
Actually, the orientation of the low-molecular liquid crystal is governed by the interface between the liquid crystal side chain components, so that the same memory properties and hysteresis characteristics as the high-molecular liquid crystal are exhibited. Thus, the conventional liquid crystal-
Low-voltage drivability and memory properties that cannot be achieved with the polymer composite film are realized.

[0023]

The present invention will be described below in more detail with reference to examples, but the present invention is not limited to these examples.
In the following description, "parts" means "parts by weight". Example 1 0.5 g of a cyanobiphenyl-based acrylic monomer represented by the following structural formula (1) as a liquid crystalline monomer and 9.5 g of ethyl methacrylate as a non-liquid crystalline polymerizable component were mixed in tetrahydrofuran with 2,2'-azobisisobutylene. Polymerization was performed using butyronitrile as a polymerization initiator to obtain a crude polymer compound. This was reprecipitated and purified using methanol to obtain 9.5 g of a polymer compound used in the present invention.
From NMR analysis, the composition of this polymer compound was almost the same as the charged composition.

[0024]

Embedded image Next, 1 part of the obtained polymer compound and a low-molecular liquid crystal (manufactured by BDH, E-4) so that the film thickness when dried becomes about 10 μm.
4) A solution obtained by dissolving 1 part in toluene was blade-coated on an ITO glass substrate to obtain a composite film. The obtained composite film was uniformly clouded visually. In addition, when observed with a polarizing microscope, the low-molecular liquid crystal formed fine domains separated from each other. On this composite membrane, ITO
Was pressed to produce a sandwich cell.

Example 2 The procedure of Example 1 was repeated except that the amount of the cyanobiphenyl-based acrylic monomer used in the synthesis of the polymer was changed to 0.1 g and the amount of ethyl methacrylate was changed to 9.0 g. Was synthesized. From NMR analysis,
The composition of this polymer compound was almost the same as the charged composition. Further, a composite membrane was obtained in the same manner as in Example 1. The obtained composite film was uniformly clouded visually. In addition, when observed with a polarizing microscope, the low-molecular liquid crystal formed fine domains separated from each other. On this composite membrane, I
The sandwiched cell was produced by pressing the PET film subjected to TO.

Comparative Example 1 In the synthesis of the polymer compound of Example 1, except that the cyanobiphenyl-based acrylic monomer was not used, that is, only the non-liquid crystal polymerizable component ethyl methacrylate was used.
Polyethyl methacrylate was obtained in exactly the same manner. A composite film was obtained in exactly the same manner as in Example 1 except that this polyethyl methacrylate was used as a polymer compound. From the viewpoint of visual observation of the obtained composite film and observation by a polarizing microscope, it was the same as the composite films of Examples 1 and 2. A sandwich type cell was produced by pressing a PET film on which ITO was applied on the composite film.

Evaluation Example 1 Using the sandwich cells prepared in Examples 1 and 2 and Comparative Example 1 as samples, the voltage-transmittance characteristics were measured by an evaluation apparatus shown in FIG. (Measurement Method of Transmitted Light Intensity) White light from a 50 W halogen lamp was incident on the sample as parallel rays by the lens system 1. At the same time, the sample was
A rectangular wave AC voltage of 100 Hz was applied. The transmitted light from the sample is allowed to reach a maximum spread angle of about ± 10 by the lens system 2.
° only the transmitted light was condensed, converted to a current by a photodiode, and the transmitted light intensity was read by a light intensity measuring instrument. The reading of the transmitted light intensity by the light intensity measuring device and the adjustment of the voltage application by the voltage application device were automatically performed by a computer. (Characteristic evaluation method) The transmittance T (%) was obtained from the measured transmitted light intensity according to the following equation. Note that I _sample ,
I _blank and I _back are as defined below.

(Equation 1) I _sample : Transmitted light intensity when a sample is set I _blank : Transmitted light intensity when a sample is removed I _back : Transmitted light intensity when light from a light source is shielded And transmitted light intensity was measured for each sample. Voltage-transmittance curve (V) representing the relationship between the voltage V at the time and the transmittance T
-T curve). In this V-T curve, a voltage V which the transmittance T is 90% of the saturation value is defined as driving voltage V _90, was subjected to characteristic evaluation of the composite film by the V _90. FIG.
There is illustrated a V-T curve illustrating the driving voltage V _90.

(Evaluation Results) Examples 1 and 2 and Comparative Example 1
The voltage-transmittance characteristics of the sandwich type cell manufactured in the above were evaluated, and the obtained characteristic values are shown in Table 1. FIG. 6 shows a VT curve created for the sample of Example 1. As is clear from Table 1, the liquid crystal-polymer composite film of the present invention has a lower driving voltage than that of the comparative example. In addition, Example 2 in which the proportion of the liquid crystalline side chain component in the polymer compound is larger has a greater effect of reducing the driving voltage, indicating that the composite film of the present invention has excellent utility. Further, as shown in FIG. 6, in the composite membrane of the present invention, the VT curve exhibits different behaviors when the voltage is increased and when the voltage is decreased. That is, it can be seen that it shows a hysteresis characteristic (memory property). Moreover, this hysteresis characteristic was reversibly observed any number of times. This is considered to be due to the development of memory properties due to the liquid crystal side chain component in the polymer compound, as described above. By using this memory characteristic, it is possible to realize a large-screen display which has been difficult in the past.

[0029]

[Table 1]

Example 3 5 parts of a cyanobiphenyl acrylic monomer represented by the above structural formula (1) as a liquid crystalline monomer, 95 parts of n-butyl acrylate as a non-liquid crystalline polymerizable component, and 2,2 'as a polymerization initiator 1 part of azobisisobutyronitrile (Wako Pure Chemical Industries, Ltd.) was mixed to obtain a liquid mixture of the polymerizable composition. A mixture of 2.5 parts of the polymerizable composition and 7.5 parts of a low-molecular liquid crystal (E-7, manufactured by BDH) became a uniform, colorless and transparent liquid at room temperature (hereinafter referred to as an injection liquid). . The infused solution was sealed under reduced pressure in an ITO glass cell having a cell gap of 10 μm, and heat-treated at 60 ° C. for 15 hours to thermally polymerize the polymerizable composition. As a result, a strongly clouded liquid crystal-polymer composite film was obtained at room temperature. Was.

Example 4 0.4 parts of a cyanobiphenyl-based acrylic monomer represented by the above structural formula (1) as a liquid crystalline monomer, 2.7 parts of n-butyl acrylate as a non-liquid crystalline polymerizable component, and ethylene glycol dimethacrylate 0.3 part and 0.05 part of 2-hydroxy-2-methyl-1-phenylpropan-1-one (manufactured by Merck) as a polymerization initiator were mixed to prepare a mixture of the polymerizable composition. 2.5 parts of this polymerizable composition and 7.5 parts of low-molecular liquid crystal (E-7, manufactured by BDH) were mixed to obtain a uniform, colorless and transparent injection at room temperature. The infused solution was sealed under reduced pressure in an ITO glass cell having a cell gap of 10 μm, and the polymerizable composition was photopolymerized by irradiation with a 500 W xenon lamp. Was.

Comparative Example 2 A liquid crystal-polymer composite film was obtained in exactly the same manner as in Example 3, except that no cyanobiphenyl-based monomer was added during the preparation of the polymerizable composition. Comparative Example 3 A liquid crystal-polymer composite film was obtained in exactly the same manner as in Example 4 except that no cyanobiphenyl-based monomer was added during the preparation of the polymerizable composition.

Evaluation Example 2 The liquid crystal-polymer composite films produced in Examples 3 and 4 and Comparative Examples 2 and 3 were evaluated as samples by the following method. While a He-Ne laser having a wavelength of 632.8 nm was vertically incident on the sample, an AC voltage of 100 Hz and a rectangular wave was applied to the sample, and the light intensity of the laser transmitted through the sample was measured while changing the applied voltage. .
From the measured transmitted light intensity, the transmittance T was determined according to Evaluation Example 1 described above. The contrast CR was determined from the VT curve according to the driving voltage _V90 and the following equation. Contrast CR = T _max / T _min where T _max and T _min are the maximum values of transmittance T, respectively.
Indicates the minimum value. The results are shown in Table 2 below.

[0034]

[Table 2] As is clear from Table 2, the samples of Examples 3 and 4 have lower driving voltages and more sufficient contrast than those of Comparative Examples 2 and 3.

[0035]

The liquid crystal-polymer composite film according to the present invention can be driven at a low voltage of 50 Vrms or less, in addition to the inherent feature that a polarizing plate is unnecessary and a bright display is possible.
It has excellent characteristics of having memory properties and having sufficient contrast and response time. Therefore, TFT
And MIM, and can be applied not only to dimming elements, but also to display elements, light modulation elements, optical shutters and memory elements, especially large screens that have been difficult to put into practical use in the past. Application to a display element (transmission and reflection mode) is also possible. Further, according to the production method of the present invention, since the liquid crystal components are mixed with the low-molecular liquid crystal and the low-molecular compound of the polymerizable composition, the droplets are easily controlled, and the driving voltage of the device tends to be low. Further, Examples 3 and 4
As shown in the above, there is an advantage that it is not necessary to dissolve the low molecular liquid crystal and the polymerizable composition in a solvent when preparing the composite film, and it is not necessary to remove the solvent after preparing the composite film.

[Brief description of the drawings]

FIG. 1 is a schematic view of a composite membrane of the present invention.

FIG. 2 is a schematic configuration diagram of a device using the composite film of the present invention.

FIG. 3 is a diagram illustrating the operation principle of the composite membrane of the present invention.

FIG. 4 is a schematic configuration diagram of a composite membrane evaluation device of the present invention.

FIG. 5 is a graph showing the relationship between the applied voltage and the transmittance of the composite film.

FIG. 6 shows a voltage-transmittance curve of the composite membrane obtained in Example 1.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Low molecular liquid crystal, 1a ... Liquid crystal molecule, 2 ... High molecular compound, 2a ... High molecular liquid crystal side chain component, 3 ...
..Liquid crystal-polymer composite film, 4, 5 ... electrode plate, 6 ...
·Power supply.

──────────────────────────────────────────────────続 き Continuing on the front page (51) Int.Cl. ⁷ Identification code FIG02F 1/13 500 C08L 101/00 (72) Inventor Toru Ishii 1600 Takematsu, Minamiashigara-shi, Kanagawa Fuji Xerox Co., Ltd. 56) References JP-A-2-116824 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G02F 1/1334 C08J 5/18 C08K 5/00 C08L 101/16 C09K 19 / 54 G02F 1/13 500

Claims (3)

(57) [Claims] 1. A low molecular liquid crystal comprising at least one kind, and a liquid
Monomers with crystalline substituents and no liquid crystalline substituents
A liquid crystal-polymer composite film comprising a copolymer with a polymerizable component and comprising at least two components of a polymer compound having at least one liquid crystalline side chain component and at least one non-liquid crystalline component in a molecule. more becomes 0.1 liquid-crystalline side-chain component and a non-liquid components of the polymer compound is a molar ratio: 100
A liquid crystal-polymer composite film, wherein the weight ratio of the low-molecular liquid crystal to the high molecular compound is 1:10 to 50: 1. 2. The liquid crystal-polymer composite film according to claim 1, wherein at least two components of the low molecular liquid crystal and the high molecular compound in the composite film exist in a phase separated state. 3. A step of preparing a mixture of a low-molecular liquid crystal, a polymerizable monomer having a liquid crystal substituent, and a polymerizable composition containing at least one polymerizable component having no liquid crystal substituent, Liquid crystalline properties of polymerizable composition
Having a polymerizable monomer having a substituent and a liquid crystalline substituent
Copolymerizing a polymerizable component having no liquid crystal substituent in the polymerizable composition, wherein the total mole number of the polymerizable monomer having a liquid crystal substituent and the total mole number of the polymerizable component having no liquid crystal substituent in the polymerizable composition are 0.1: 100 to 100: 1, and the weight ratio of the low-molecular liquid crystal and the polymerizable composition in the mixture is 1:10 to 5
2. The method for producing a liquid crystal-polymer composite film according to claim 1, wherein the ratio is 0: 1.