JPH05341273A - Polymer dispersion type liquid crystal composite film and its production - Google Patents

Abstract

PURPOSE: To provide a polymer dispersion type liquid crystal composite film having low driving voltage, high contrast and high retention by using a liquid crystal material having a functional group of F or Cl, which is chemically stable polar group, as a essential structural atom and a high polymer material. CONSTITUTION: The liquid crystal material selected from compounds expressed by formula I and formula II, and containing 50-100wt.% in total of both compounds is uniformly mixed with a photoradically polymerizable resin material having average solubility parameter of 8-11 and the average molecular weight of 100-1000 and the liquid crystal material is phase separated by photopolymerizing the polymerizable resin material. In formula I, each of A1 and A2 represents benzene ring, cyclohexane ring or the like, each of X1 -X6 represents H, F and Cl. Each of Z1 , Z2 and Q represents a single bond, -CH2 - or the like, Y represents H, F or Cl, R represents Cn H2n-1 - or the like, (m) is 0-2. And in formula II, each of B and C represents Cn H2n-1 -, Cn H2n-1 O or the like and L represents H or F.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a polymer dispersion type liquid crystal composite film. More specifically, a polymer-dispersed liquid crystal composite film using a display mode in which the difference in refractive index between liquid crystal droplets or continuous liquid crystal droplets and a polymer is changed by an external voltage to control light scattering occurring at the interface between the liquid crystal and the polymer. Regarding Specifically, the polymer-dispersed liquid crystal composite film of the present invention can be used for liquid crystal display devices, projection televisions, flat panel display devices such as personal computers, or display plates, windows, doors or walls using the shutter effect. it can.

[0002]

2. Description of the Related Art Conventionally, TN type and STN type using nematic liquid crystal have been put to practical use as display elements utilizing the electro-optical effect. Also, a device using a ferroelectric liquid crystal has been proposed. These require a polarizing plate and require an alignment treatment. on the other hand,
There are dynamic scattering (DS) mode, phase transition (PC) mode, and the like that utilize liquid crystal scattering without the need for a polarizing plate.

Recently, there has been proposed a method of electrically controlling a transparent or opaque state by utilizing the birefringence of a liquid crystal, which does not require a polarizing plate and does not require an alignment treatment. This method basically matches the ordinary refractive index of the liquid crystal molecules with the refractive index of the support medium, displays a transparent state when a liquid crystal is aligned by applying a voltage, and displays a transparent state when no voltage is applied. The light scattering state due to the disordered orientation is displayed.

A proposed method is Japanese Patent Laid-Open No. 58-58.
No. 501631 discloses a method of encapsulating a liquid crystal in a polymer capsule, and JP-A No. 61-502128 discloses that a liquid crystal compound is precipitated by mixing the liquid crystal with a light or thermosetting resin and curing the resin to precipitate the liquid crystal in the resin. A method of forming droplets is disclosed in JP-A-59-226322, in which a phase separation state of a liquid crystal and a polymer is formed by removing the solvent from a mixture of a polymer and a liquid crystal and a solvent which dissolves the mixture. A featured method is disclosed.

Most of the liquid crystal compounds used in the polymer dispersion type liquid crystal display device produced by these inventions are cyanobiphenyl compounds and cyanopyrimidine compounds having a --CN group at the molecular end. Examples of these liquid crystal compounds include JP-A-2-272422 to 272424, JP-A-2-75688, JP-A-2-28284, and JP-A-2-72824.
It is disclosed in Japanese Patent Publication No. 85822.

Further, the element manufactured by using the liquid crystal compound described in the above publication has hysteresis due to electro-optical characteristics (light transmittance is different when voltage rises and when voltage falls), and T
When the FT drive is performed, gradation display is different when the voltage rises and when the voltage falls. Therefore, when using these elements as a projection type display, having a hysteresis was a fatal defect. As a method of lowering the hysteresis, a method of adding a monobasic chromium complex into a photocurable resin has been proposed (Procedures of the 17th Liquid Crystal Conference, page 312). However, in this method, the use of ions lowers the electric retention rate, and the effect is not sufficient, so that it cannot be put to practical use.

[0007]

A liquid crystal compound having a --CN group at a terminal, which is conventionally used in a polymer-dispersed liquid crystal display device, is highly reactive due to the strong polarization of the --CN group and the entire system. Easy to take in impurities. Therefore, a high retention rate (90%) is maintained throughout the manufacturing process of the polymer dispersion type liquid crystal display device, which is often in contact with other substances.
It is difficult to manufacture a polymer dispersion type liquid crystal display device capable of maintaining a charge retention rate (equal to or more%) (retention rate means a rate in which electric charge is retained within 16.5 ms after voltage application).

In particular, in the method of curing the curable compound from the mixture of the liquid crystal compound and the curable compound and phase-separating the liquid crystal from the cured product, since the liquid crystal compound and the polymerization reaction active substance coexist in the cell, During the curing of the curable compound, the liquid crystal compound is damaged due to its high reactivity, and the retention rate of the resulting liquid crystal element becomes extremely low.

On the other hand, in order to reduce the hysteresis, it is conceivable to add a photocurable resin having the ability to form a low energy surface, but such a resin has an SP value with that of a conventionally used liquid crystal. However, it was difficult to be compatible and could not be put to practical use.

When the compatibility between the liquid crystal material and the resin material is poor, in the method of mixing the liquid crystal and the photocurable resin and causing the phase separation between the liquid crystal and the polymer by photopolymerization, the liquid crystal and the photocurable resin are mixed and uniformly mixed. Since there is a step of liquefying, the mixing temperature must be raised in order to match the resin with the compatibility parameter (SP value) of the liquid crystal. When phase separation due to photopolymerization occurs at such a high temperature, the polymerization rate is increased and the phase separation is completed in a nearly uniform state, so that the liquid crystal dispersed particles are small and the driving voltage is high. Furthermore, since the liquid crystal is injected into the cell at a high temperature, it becomes difficult to inject a mixture to which a resin material having a higher vapor pressure than liquid crystal is added in a vacuum.

The present invention has been made in view of the above circumstances, and is a polymer-dispersed liquid crystal composite satisfying all of the low driving voltage, high contrast, and high retention, which are considered to be the most important requirements of the polymer-dispersed liquid crystal display device. The purpose is to provide a membrane.

The object of the invention is to provide a liquid crystal compound having a structure different from the conventional one, that is, a liquid crystal material group (functional material, Vol2) having a functional group containing an atom such as F or Cl which is a chemically stable polar group as a main constituent atom. , No. 2, p5-12), and has a large refractive index anisotropy (Δn) that is said to be closely related to the contrast of the polymer dispersion type liquid crystal display element, It is achieved by using a liquid crystal material having an important clearing point (nematic phase-isotropic liquid transition temperature) of 60 to 100 ° C. and optimizing the resin composition.

[0013]

That is, the present invention is
(A) A compound selected from the group consisting of the compound represented by the following "Chemical Formula 3" and a compound selected from the group consisting of the compound represented by the following "Chemical Formula 4" in a total amount of 50% by weight to The liquid crystal material contained at a ratio of 100% by weight was uniformly mixed with (b) a photo-radical polymerizable resin material having an average solubility parameter (SP) value of 8 to 11 and an average molecular weight (Mn) of 100 to 1000, and this polymerization was carried out. Relates to a process for producing a polymer-dispersed liquid crystal composite film, which comprises subjecting a liquid crystal material to phase separation by photopolymerizing a photosensitive resin material;

[Chemical 3] (In the formula, A ₁ and A ₂ each independently represent a benzene ring, a cyclohexane ring, a pyrimidine ring, a pyridine ring, or a trans-1,3-dioxane ring; X ₁ , X ₂ , X ₃ ,
X ₄ , X ₅ and X ₆ each independently represent H, F or C ₁ ; Z ₁ and Z ₂ are each independently a single bond, —CH ₂ —, —
_{CH 2 CH 2 -, - CH} = CH -, - C≡C -, - COO
- or an -OCO-; Q is a single bond, -CH ₂ -,
_{-CH 2 CH 2 -, - CF} 2 -, - OCF 2 -, - C 2 F
₄ -, - CCl ₂ - or -C ₂ Cl ₄ - represents a; Y is, H,
F or Cl; R is, C _n H _{2n + 1} - or, C _n H
_{2n + 1 O-, C n H} 2n + 1 CH = CH- ( wherein, n 2-10
Represents an integer); m represents 0, 1, 2);

[Chemical 4] (In the formula, B and C are independently C _n H _{2n + 1} −, C _n H _{2n + 1
O-, C n H 2n + 1} CH = CH- or _{C n H 2n + 1 · C} 6 H
₁₀ − (in the formula, n has the same meaning as described above); L represents H or F).

The liquid crystal compound represented by "Chemical Formula 3" is particularly excellent in chemical stability, and the higher the content thereof, the more chemically stable it is. However, with this compound alone, the refractive index anisotropy (Δn), which is closely related to the contrast of the polymer dispersion type liquid crystal display element, is small. In order to increase the refractive index anisotropy (Δn) of the liquid crystal material of the present invention, it has no strong polar group, is excellent in chemical stability, and has an effect of increasing the refractive index anisotropy (Δn). A liquid crystal compound as shown in Chemical formula 4 ”is added. This compound has a great effect of increasing the refractive index anisotropy (Δn), but in order to reduce the dielectric anisotropy (Δε), it is preferably 30% by weight or less based on the whole liquid crystal material.

In the present invention, other liquid crystal materials may be mixed, but in this case, it is prevented that the chemical stability of the entire liquid crystal material is remarkably lowered and the retention rate of the polymer dispersion type liquid crystal display element is lowered. Therefore, the content of the liquid crystal compounds represented by the above “Chemical Formula 3” and “Chemical Formula 4” is 50 to 100% by weight, and more preferably 70% by weight or less.
Up to 100% by weight.

The compounds represented by "Chemical Formula 3" and "Chemical Formula 4" are in the range of 99: 1 to 20:80 ((Chemical Formula 3) :( Chemical Formula 4)), preferably 97: 3. It is used in a ratio range of ˜50: 50, more preferably in a ratio range of 95: 5 to 75:25. If the ratio is larger than 99: 1, Δn does not become large, and if it is smaller than 20:80, Δε becomes small and the driving voltage becomes high, which is not suitable.

As the liquid crystal compounds other than the liquid crystal compounds represented by "Chemical Formula 3" and "Chemical Formula 4", liquid crystal materials generally used for polymer dispersion type liquid crystal display devices such as cyanobiphenyl type and cyanopyrimidine type are used. be able to.

The liquid crystal material used must be sufficiently purified, and the specific resistance after mixing the liquid crystal material is 10 ¹² Ω.
-Cm or more, preferably 10 ¹³ Ω-cm or more.

In the compounds represented by "Chemical formula 3" and "Chemical formula 4", the larger the number of benzene rings and / or cyclohexane rings (N) in the molecule, the larger the refractive index anisotropy (Δn). .. However, when a compound having a ring number (N) of N ≧ 4 is added, the clearing point of the entire liquid crystal is pushed up. In particular, in the case of a method utilizing phase separation by curing a mixture of a liquid crystal material and a photo-radical polymerizable resin material, the processing temperature becomes high, and the phase separation speed increases accordingly, so that the liquid crystal dispersed particles become extremely small. As a result, the driving voltage of the liquid crystal display element using the same becomes high. From this point of view, it is not possible to add many compounds with N ≧ 4. Further, a compound having a ring number (N) of N ≦ 2 or less lowers the refractive index anisotropy (Δn) of the liquid crystal material as a whole,
Also in this case, the compound cannot be added in a large amount. Accordingly, among the liquid crystal compounds represented by “Chemical Formula 3” and “Chemical Formula 4”, the compound having a total of three benzene rings and / or cyclohexane rings in the molecule is represented by “Chemical Formula 3” and “Chemical Formula 4”. It is desirable that the content of the compound is 60% by weight or more, preferably 90% by weight or more.

Further, a compound such as a dopant, a cholesteric liquid crystal or a dye (dichroic dye) may be added to such an extent that the chemical stability of the liquid crystal material of the present invention is not impaired.

The photopolymerizable resin material in the present invention is a mixture of compounds selected from monofunctional monomers, polyfunctional monomers and their oligomers, and is photopolymerizable. The polymerizable resin material is a resin material that satisfies the following SP value and molecular weight constraints, and the mixing ratio of the constituent monomers and oligomers is an important factor that determines the compatibility temperature with the liquid crystal material.

The resin material preferably has a chemical structure (solubility parameter (SP) value) matching the above liquid crystal material. If the SP value greatly deviates from that of the liquid crystal material, the compatibility between the liquid crystal and the resin deteriorates, and the mixing temperature must be increased in order to make it uniform. When the phase separation by photopolymerization is induced at a high temperature, the polymerization rate becomes fast and the phase separation is completed in a state close to a uniform state, so that the liquid crystal droplet becomes small and the driving voltage becomes high. As the SP value of the photopolymerizable resin material, the SP value of the above liquid crystal material is 9.
Since it is around 5, it is preferably 8 to 11, and more preferably 9 to 10.

In the present invention, the SP value δ is generally the Fedor
It is calculated by the following "Equation 1" known as the method of s.

## EQU1 ## δ = √ (ΣΔei / ΣΔvi) (where Δei is the evaporation energy of an atom or atomic group,
Δvi represents the molar volume of an atom or an atomic group, respectively).

In the present invention, when several kinds of resins are mixed and used, the SP value of the mixed resin is defined by the following "Equation 2".

[Formula 2] δ = (X ₁ · δ ₁ + X ₂ · δ ₂ + X ₃ · δ ₃ + ...
+ Xn · δn) / 100 (where Xn is the weight% of the nth resin component, and δn is the SP value of the nth resin component)

Further, the molecular weight of the radical photopolymerizable resin material has a significant effect on the homogenization temperature when the liquid crystal material and the resin material are mixed and homogenized. For example, in the case of a photopolymerizable oligomer, the SP value hardly changes even if the molecular weight changes, but the enthalpy of the molecule decreases as the molecular weight increases. As a result, the solubility in the liquid crystal is lowered, and as a result, the homogenization temperature is raised. Therefore, the average molecular weight of the polymerizable resin material is 100 to 1000.
Is preferred. When it is 100 or less, the ratio of the monofunctional monomer increases, sufficient curing cannot be obtained, the vapor pressure of the polymerizable resin material becomes high, vacuum injection becomes difficult, and the toxicity becomes high, which is not suitable for industrial production. The average molecular weight is 100
When it is 0 or more, the homogenizing temperature of the liquid crystal is high, the polymerization rate is inevitably high, the particle size of the liquid crystal dispersed particles produced is small, and the driving voltage is high, which is not suitable. More preferably, the average molecular weight of the resin is in the range of 150 to 300.

The molecular weight (M ₀ ) of the oligomer referred to in the present invention
And gel permeation chromatography (GP
C) The weight average molecular weight (monodisperse polymethylmethacrylate (PMMA) is used as a standard) determined by the method.

In the present invention, the average molecular weight (M) of a mixture of compounds having different chemical structural formulas is defined by the following "Equation 3".

[Equation 3] M = (X ₁ · M ₁ + X ₂ · M ₂ + X ₃ · M ₃ + ...
Xn · Mn) / 100 (where Xn represents the weight% of the nth resin component, and Mn represents the average molecular weight of the nth resin component)

In particular, the monofunctional monomer is preferably contained in the polymerizable resin material in a proportion of 60 to 98%. When the content of the monofunctional monomer in the polymerizable resin material is 60% or less, the following problems occur. That is, the molecular weight of the polymerizable resin material increases, and the compatibility temperature between the liquid crystal material and the resin material increases. Moreover, since the polyfunctional monomer has an effect of developing the network structure of the polymer, the polyfunctional monomer remarkably accelerates the phase separation speed between the liquid crystal molecule and the polymer. For example, the particle size of the generated liquid crystal dispersed particles is reduced and the driving voltage is increased. In addition, the content of the monofunctional monomer in the resin is 98.
%, The polymer matrix having sufficient strength cannot be obtained, and the sufficient phase separation rate cannot be obtained, so that the particle size of the liquid crystal dispersed particles becomes large. Therefore, the contrast of the manufactured cell is significantly reduced.

The total amount of polyfunctional monomers and oligomers is preferably 2 to 40% by weight, more preferably 10 to 30% by weight in the polymerizable resin material. Both may be used alone or in combination. The content of polyfunctional monomer is preferably 5 to 25% by weight, more preferably 8 to 15% by weight, and the amount of oligomer is 5 to 20% by weight, more preferably 8 to 15% by weight.

Specific monomers constituting the polymerizable resin material include benzene ring, linear alkyl, branched alkyl, among acrylic acid and acrylic acid ester derivatives.
Further, a compound having an alkyl chain or a benzene ring in which one or all of hydrogen atoms are replaced by F or Cl atoms in the molecule can be used.

More specifically, as monofunctional monomers, isobutyl acrylate, stearyl acrylate, lauryl acrylate, isoamyl acrylate, n-butyl methacrylate, n-lauryl methacrylate, tridecyl methacrylate, n-stearyl methacrylate. , Cyclohexyl methacrylate, benzyl methacrylate, 2-ethylhexyl acrylate, 2-phenoxyethyl methacrylate, bisphenol A dimethacrylate, bisphenol A diacrylate and the like are applicable.

The bifunctional or higher polyfunctional monomer functions to increase the physical strength of the polymer, and for example, 1,4-butanediol dimethacrylate, 1,6-hexanediol dimethacrylate, trimethylolpropane trimethacrylate, Trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, etc. can be applied.

Further, it is more preferable to add a fluorinated, chlorinated or silicified compound of the above-mentioned monomer, which has an effect of reducing the interaction at the interface between the liquid crystal material and the resin and lowering the hysteresis. The addition amount of these fluorinated, chlorinated or silicified monomers is preferably 0.1 to 50% by weight based on the total amount of the polymerizable resin material. If it is less than 0.1% by weight, the effect of reducing the hysteresis is weak. When it is 50% by weight or more, the compatibilization temperature is increased due to the difference in SP value with other monomers, which is not practical. Examples of the fluorinated, chlorinated or silicified compound include 2,2,3,4,4,4-hexafluorobutyl methacrylate, 2,2,3,4,4,4-hexachlorobutyl methacrylate and 2,2. , 3,3-Tetrafluoropropylmethacrylate, 2,2,3,3-tetrafluoropropylmethacrylate, perfluorooctylethylmethacrylate, perchlorooctylethylmethacrylate, perfluorooctylethylacrylate, perchlorooctylethylacrylate can be used is there.

As the oligomer, urethane acrylate or polyoxyethylene acrylate can be used.

In the polymer-dispersed liquid crystal composite film, the liquid crystal material, the photopolymerizable resin material, the photopolymerization initiator and, if desired, other additives are uniformly mixed in a predetermined amount to prepare a uniform mixed liquid. The liquid crystal material and the photopolymerizable resin material are used in a ratio of 100 to 500 parts by weight, preferably 300 to 500 parts by weight with respect to 100 parts by weight of the former.

As the photopolymerization initiator, those conventionally used may be used, and the amount thereof is 0.1 to 30% by weight, preferably 1 to 20% by weight, more preferably 1 to 20% by weight based on the polymerizable resin material. Is 5 to 15% by weight. 0.1% by weight
If it is less than the above range, curing does not sufficiently occur, and if it is more than 30% by weight, the molecular weight of the produced polymer is lowered, the strength of the resin matrix is lowered, and the retention rate is not suitable, which is unsuitable.

The polymer-dispersed composite film is obtained by injecting the above-mentioned homogeneous mixture into a desired cell or device, irradiating it with light, and polymerizing the photoradical-polymerizable resin material, thereby phase-separating the liquid crystal material from the polymerized resin. It is formed by The conditions of light irradiation are not particularly limited, but a light source containing light having a wavelength of 400 nm or less is preferable, and for example, a high pressure mercury lamp, a low pressure mercury lamp, a metal halide lamp, etc. can be used. The light irradiation conditions vary depending on the type of resin and are not particularly limited, but the intensity of directly hitting the mixture of the liquid crystal and the resin material is 1 to 400 mW / cm ² (measured at 365 nm).
Is preferred. When it is 1 or less, the phase separation rate becomes slow, and the scattering intensity decreases. On the other hand, when it is 200 or more, a decomposition reaction occurs due to a photoreaction, and the retention rate decreases. The irradiation temperature is preferably the temperature at which the surface tension of the liquid crystal is high and the liquid crystal droplets tend to become spherical, and the compatibility temperature of the mixture of the liquid crystal and the resin and the range within 20 ° C. from the temperature are preferable. Below the compatibility temperature, phase separation occurs before UV curing, resulting in non-uniform liquid crystal droplets.

The polymer dispersion type composite film obtained as described above can be applied to the liquid crystal display device shown in FIGS. 1 and 2, for example. The device is constituted by interposing the polymer dispersed composite film (8) of the present invention as a liquid crystal layer between a display electrode substrate and a counter electrode substrate. In addition to bus lines such as signal lines (2) and scanning lines (3), a pixel electrode (5) and a switching transistor associated therewith are formed on a transparent insulating substrate (1) made of glass without birefringence. The active matrix drive type display electrode substrate is formed by arranging (4) in a matrix. The switching transistor (4) is a
-Si thin film transistor (TFT) is formed. The counter electrode substrate is formed by forming a counter electrode (7) on a transparent insulating substrate (6) also made of glass so as to face each picture element electrode (5) of the display electrode substrate. The picture element electrode (5) and the counter electrode (7) are transparent electrodes for applying a voltage to the liquid crystal layer (8) and are made of ITO. The liquid crystal layer (8) is sealed by a seal (9) made of epoxy resin.

[0039]

EXAMPLES The present invention will be described in more detail below with reference to examples, but the scope of the present invention is not limited to these examples.

Examples 1, 2, 3, 2-ethylhexyl acrylate (2EHA; SP value δ: 8.6, average molecular weight (Mn): 184, liquid resistivity value: 1.2 × 10 ¹² Ω · cm; Japaneseized Yakusha) and diacrylic monomer (R-684; SP value δ: 10.3, average molecular weight (Mn): 304, liquid specific resistance value: 2.1 × 10 ¹² Ω · c
m; manufactured by Nippon Kayaku Co., Ltd.) was mixed at a ratio shown in Table 1 to prepare a photoradical polymerizable resin material. The average molecular weight and SP value of the prepared polymerizable resin material are also shown in Table 1.

[0041]

[Table 1]

0.3 g of these polymerizable resin materials, 1.2 g of liquid crystal material A (manufactured by Merck & Co., Inc.) shown in Table 2 and a photoinitiator (Irgacu
re184: manufactured by Ciba-Geigy) 0.045 g was uniformly mixed at 80 ° C.

[0043]

[Table 2]

A cell was formed between two ITO-containing glass (a mixture of indium oxide and tin oxide) (flint glass with ITO-500Å; manufactured by Nippon Sheet Glass Co., Ltd.) via a 12 μm spacer, and the mixture was injected. After that, the ultraviolet (UV) irradiation temperature is 15 ° C, and the UV irradiation intensity under a low-pressure mercury lamp is 50 mW / cm ² (UV irradiation intensity at 365 nm: UV illuminometer U).
The resin material was polymerized and cured by irradiating it with ultraviolet rays for 20 seconds with IT-101: manufactured by Ushio Inc.). After UV irradiation, it was left at 50 ° C. for 2 hours.

The retention rate of the prepared cell was measured by the retention rate measuring system shown in FIG. This system is a switching transistor (F
ET), a drive circuit, and a circuit for measuring discharge of electric charge stored in the cell. Table 3 shows the measurement results measured at room temperature. As a result, Examples 1, 2, and 3 showed high retention rates of 95% or more.

Further, the electro-optical characteristics of the manufactured cell are
10% of the value obtained by subtracting the light transmittance (T ₀ ) when no voltage is applied from the saturation transmittance (Ts) when the voltage is excessively high, the applied voltage ( (Threshold voltage)
(Vth), saturation voltage (V
s), the light transmittance (T ₀ ) when no voltage is applied and the light transmittance (T ₁₀₀ ) when a 50 V AC voltage is applied when the light collection angle of the light receiving portion is 6 ° are also shown in Table 3.

[0047]

[Table 3]

Examples 4 and 5, Comparative Examples 1 and 2, Liquid Crystal Material B (Example 4) (Table 4), Liquid Crystal Material C (Example 5)
(Table 5), cyanobiphenyl liquid crystal E8 (manufactured by Merck,
A polymer-dispersed liquid crystal display device was produced in the same manner as in Example 2 except that Comparative Example 1) and E44 (Comparative Example 2 manufactured by Merck & Co., Inc.) were each replaced with the liquid crystal material A (Table 2) shown in Example 2. did.

[0049]

[Table 4]

[0050]

[Table 5]

The retention rate of the prepared cell was measured in the same manner as in Example 2, and Table 6 shows the results of Example 4 and Example 5.

[0052]

[Table 6]

In Comparative Examples 1 and 2, the polymerizable resin material and the liquid crystal material were not mixed at a low temperature, and the compatibility temperatures were 80 and 85, respectively.
It was ℃. The prepared cell had almost no change in light transmittance even when applied with 50 V and had a retention rate of 8 each.
It is 5.1, 83.8%, which is not practical.

Comparative Examples 3 and 4 Using the same compounds as in Example 1, resin materials having the compositions shown in Table 1 were prepared, and a liquid crystal material A (Table 2) was used. A device was produced. Table 7 shows the electro-optical characteristics of the manufactured cell.

[0055]

[Table 7]

Examples 6, 7 and 8 2-Ethylhexyl acrylate (2EHA; SP value δ: 8.6, average molecular weight (Mn): 184; manufactured by Nippon Kayaku Co., Ltd.) and diacrylate monomer (R-684; SP value) δ:
10.3; average molecular weight (Mn): 304; manufactured by Nippon Kayaku Co., Ltd.)
And urethane acrylate oligomer (SP value δ: 10.
3; average molecular weight (Mn): 1700; liquid resistivity: 1.
5 × 10 ¹² Ω · cm (manufactured by Nippon Kayaku Co., Ltd.) were mixed at a ratio shown in Table 5 to prepare a polymerizable resin material. The average molecular weight and SP value of the prepared resin material are shown in Table 8.

[0057]

[Table 8]

Using these resin materials and liquid crystal material A (Table 2), a polymer dispersion type liquid crystal display device was produced in the same manner as in Example 1. Table 9 shows the electro-optical characteristics of the manufactured cell.

[0059]

[Table 9]

Examples 9, 10 and 11 2-Ethylhexyl acrylate (2EHA; SP value δ: 8.6; average molecular weight (Mn): 184; manufactured by Nippon Kayaku Co., Ltd.) and perfluorooctylethyl acrylate (FA-1).
08; SP value δ: 7.4; average molecular weight (Mn): 57
8; Kyoeisha Co., Ltd., diacryl monomer (R-684; S
P value δ: 10.3; average molecular weight (Mn): 304; manufactured by Nippon Kayaku Co., Ltd. and urethane acrylate oligomer (SP value δ: 10.3; average molecular weight (Mn): 1700; liquid resistance value: 1.1 × 10 ¹² Ω · cm (manufactured by Nippon Kayaku Co., Ltd.) was mixed at a ratio shown in Table 10 to prepare a polymerizable resin material. Table 10 also shows the average molecular weight (Mn) and SP value of the prepared resin material.

[0061]

[Table 10]

Using these resin materials and liquid crystal material A (Table 2), a polymer dispersion type liquid crystal display device was produced in the same manner as in Example 1. Measurements of the electro-optical characteristics, the same measurement as in Example 1, the hysteresis, the difference V ↑ ↓ and V ₅₀ ↑ of V ₅₀ ↓ voltage during rise when a voltage lowered (V ₅₀ ↓ -V ₅₀ ↑) It was measured.
Table 11 shows the electro-optical characteristics of the manufactured cell. Note the change in light transmittance and V ₅₀ is 50% of the whole change
The voltage when it changes.

[0063]

[Table 11]

Comparative Examples 5 and 6 The same repeating unit as the urethane acrylate oligomer used in Examples 6, 7 and 8 had an average molecular weight (Mn) of 25.
Example 1 except that the compound of No. 00 was used (Comparative Example 5), while 2EHA 100% (Comparative Example 6) was used as the photo-radical polymerizable resin material, and the same liquid crystal material as in Example 1 was used. A polymer dispersion type liquid crystal display device was produced in the same manner as in (Table 8 shows the composition of the resin material). Table 12 shows the electro-optical characteristics of the manufactured cell.

[0065]

[Table 12]

In Comparative Example 5, the saturation voltage was 50 V or higher. Further, in Comparative Example 6, curing did not sufficiently occur and sufficient contrast was not obtained.

Comparative Example 7 2-hydroxyethyl acrylate (light ester HOA; SP value δ: 12.5; instead of 2EHA of Example 2;
A molecular weight (Mn); 116; manufactured by Kyoeisha Co., Ltd. was used and mixed with the liquid crystal material A (Table 2), but the cell could not be prepared without mixing even at 80 ° C. Table 13 shows the composition of the resin material.

[0068]

[Table 13]

[0069]

According to the present invention, chemically stable F and C are used.
By combining an l-based liquid crystal material and a polymerizable resin material suitable for the liquid crystal material, there is no problem of low retention ratio which is the most obstacle in polymer dispersion type liquid crystal display, and low voltage drive, high contrast and low hysteresis It is possible to obtain a highly reliable polymer-dispersed liquid crystal film having excellent display quality such as properties.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing one embodiment of a liquid crystal display device that can use a polymer-dispersed liquid crystal composite film according to the present invention.

FIG. 2 is a schematic cross-sectional view showing one embodiment of the liquid crystal display element.

FIG. 3 is a circuit of a device for measuring retention rate.

[Explanation of symbols]

1 First Transparent Insulating Substrate 2 Signal Electrode 3 Scanning Electrode 4 Switching Transistor 5 Display Pixel Electrode 6 Second Transparent Insulating Substrate 7 Counter Electrode 8 Liquid Crystal Layer 9 Seal

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[Procedure amendment]

[Submission date] September 18, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 4

[Correction method] Change

[Correction content]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0035

[Correction method] Change

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In the polymer-dispersed liquid crystal composite film, the liquid crystal material, the photopolymerizable resin material, the photopolymerization initiator and, if desired, other additives are uniformly mixed in a predetermined amount to prepare a uniform mixed liquid. The photopolymerizable resin material and the liquid crystal material are used in a ratio of 100 to 500 parts by weight, preferably 300 to 500 parts by weight of the latter with respect to 100 parts by weight of the former.

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[Table 3]

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[0052]

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─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical indication location C09K 19/44 7457-4H 19/52 7457-4H G09F 9/35 303 6447-5G (72) Invention Nobuaki Yamada 22-22 Nagaike-cho, Abeno-ku, Osaka-shi, Osaka Prefecture Sharp Corporation (72) Inventor Toshiyuki Hirai 22-22, Nagaike-cho, Abeno-ku, Osaka City Osaka Prefecture (72) Inventor Noriaki Onishi Osaka 22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka Prefecture (72) Inventor Shuichi Kanzaki 22-22, Nagaike-cho, Abeno-ku, Osaka-shi, Osaka Prefecture (72) Inventor David Coates United Kingdom, England, B21 21 Es W, Dorset, Wyborne, Marley, Sopwith Cresent 87 (72) Inventor Bernhard Rieger 2834 Otadaira, Nara-cho, Midori-ku, Yokohama-shi, Kanagawa W-Colle Tamagawa Gakuen B-511 (72) Inventor Masaomi Tanaka 3-22-1, Tsumada Nishi, Atsugi-shi, Kanagawa Pure Heights Yoshimura 202

Claims (5)

[Claims] 1. A total amount of a compound selected from the group consisting of a compound represented by the following “Chemical formula 1” and a compound selected from a group consisting of a compound represented by the following “Chemical formula 2”. In a proportion of 50 wt% to 100 wt% in (b) a photo-radical polymerizable resin material having an average solubility parameter (SP) value of 8 to 11 and an average molecular weight (Mn) of 100 to 1000 A method for producing a polymer-dispersed liquid crystal composite film, characterized in that the liquid crystal material is phase-separated by photopolymerizing the polymerizable resin material. (In the formula, A ₁ and A ₂ each independently represent a benzene ring, a cyclohexane ring, a pyrimidine ring, a pyridine ring, or a trans-1,3-dioxane ring; X ₁ , X ₂ , X ₃ ,
X ₄ , X ₅ and X ₆ each independently represent H, F or C ₁ ; Z ₁ and Z ₂ are each independently a single bond, —CH ₂ —, —
_{CH 2 CH 2 -, - CH} = CH -, - C≡C -, - COO
- or an -OCO-; Q is a single bond, -CH ₂ -,
_{-CH 2 CH 2 -, - CF} 2 -, - OCF 2 -, - C 2 F
₄ -, - CCl ₂ - or -C ₂ Cl ₄ - represents a; Y is, H,
F or Cl; R is, C _n H _{2n + 1} - or, C _n H
_{2n + 1 O-, C n H} 2n + 1 CH = CH- ( wherein, n 2-10
Represents an integer of 0); m represents 0, 1, or 2); (In the formula, B and C are independently C _n H _{2n + 1} −, C _n H _{2n + 1
O-, C n H 2n + 1} CH = CH- or _{C n H 2n + 1 · C} 6 H
₁₀ − (in the formula, n has the same meaning as described above); L represents H or F). 2. A polymerizable fluorinated material in the photopolymerizable resin material,
The method for producing a polymer-dispersed liquid crystal film according to claim 1, comprising at least one kind of chlorinated or silicified resin material. 3. The photopolymerizable resin material is a monofunctional monomer,
The content of monofunctional monomers selected from polyfunctional monomers and their oligomers is 6% of that of photopolymerizable resin materials.
The manufacturing method according to claim 1, which is 0 to 98% by weight. 4. The method according to claim 1, wherein the compounding ratio of the liquid crystal material and the photopolymerizable resin material is 100 to 500 parts by weight of the latter with respect to 100 parts by weight of the former. 5. A polymer-dispersed liquid crystal film produced by the method of claim 1.