JPH0757845B2 - Ferroelectric liquid crystal composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to a ferroelectric liquid crystal composition which is preferably used as a liquid crystal material for liquid crystal display devices, liquid crystal storage devices, liquid crystal acoustic devices and the like.

[Conventional technology]

In recent years, a liquid crystal optical element formed by using a ferroelectric liquid crystal as a liquid crystal material, highly controlling the orientation of the liquid crystal, and sandwiching the liquid crystal material between two substrates provided with electrodes is Since it has excellent characteristics such as high-speed response to external stimuli and excellent contrast, it has been widely used as a liquid crystal display element, a liquid crystal storage element, and the like.

For example, Japanese Patent Application Laid-Open No. 63-109418 describes a composite liquid crystal material composed of a non-liquid crystal polymer substance and a low molecular weight ferroelectric liquid crystal. However, since a low molecular weight liquid crystal is used, a film is formed. Since the property depends only on the polymer, it is difficult to form a thin film having a thickness of several μm or less, and there is a problem that the mechanical strength of the device after the device is manufactured is not sufficient. Furthermore, although the orientation of the liquid crystal is controlled by stretching, it is difficult to obtain a high degree of orientation by stretching using a low-molecular liquid crystal,
Further, since the liquid crystal is aligned along the polymer aligned by stretching, it is difficult to sufficiently exhibit bistability.

Further, JP-A-63-137211 discloses that a liquid crystal is dispersed in a resin matrix and a scattering / non-scattering state of light is created by applying an electric field to use it as a blind. Since liquid crystal is used, the response time is long, and light is turned on and off by scattering / non-scattering, so that the contrast is low and it is not sufficient as a display element.

[Problems to be Solved by the Invention]

The present invention has been made based on the above circumstances, and an object thereof is to have excellent film-forming properties and alignment properties when manufacturing a liquid crystal optical element, and to provide dimensional stability and shock resistance when formed into an element. It is intended to provide a ferroelectric liquid crystal composition having excellent mechanical strength such as properties and contrast, and having a fast response to an electric field.

[Means for Solving the Problems]

As a result of intensive studies to solve the above problems, the present inventors have found that the above object can be achieved by a liquid crystal composition in which a specific adhesive is mixed with a ferroelectric polymer liquid crystal, and this finding The present invention has been completed based on the above.

That is, the present invention comprises 20 to 97% by weight of at least one ferroelectric polymer liquid crystal and 3 to 80% by weight of at least one adhesive selected from an epoxy thermosetting adhesive and an acrylic UV curable adhesive. The present invention provides a ferroelectric liquid crystal composition obtained by blending

The ferroelectric polymer liquid crystal used in the present invention is not particularly limited as long as it has ferroelectricity, but one having a number average molecular weight of 1000 or more is preferably used. Further, it is not limited to a homopolymer and may be a copolymer.

The representative ones are listed below.

Ferroelectric polymer liquid crystal having polyacrylate main chain (JP-A-63-99204) Ferroelectric polymer liquid crystal having polymethacrylate main chain (JC Dubois et al., Mol. Cryst. Liq. Cryst., 1986, 137, 349) Ferroelectric polymer liquid crystal having polychloroacrylate main chain (JC Dubois et al., Mol. Cryst. Liq. Cryst., 1986, 137, 349) Ferroelectric polymer liquid crystal having polyoxirane main chain (JP-A-63-264629) Ferroelectric polymer liquid crystal having polysiloxane main chain (Applied by the applicant as Japanese Patent Application No. 62-114716) Ferroelectric polymer liquid crystal having a polyester main chain (Applied by the applicant as Japanese Patent Application No. 62-173205) (Applied by the applicant as Japanese Patent Application No. Sho 62-179140) (R.Zentel et al., Liq. Cryst. 1987,2,83) The side chain (mesogen) part of each polymer liquid crystal has various skeletons known in low-molecular liquid crystals (eg, biphenyl skeleton, phenylbenzoate skeleton). , Biphenyl benzoate skeleton, phenyl-4-phenyl benzoate skeleton). And the benzene ring in each skeleton is
Each of them may be replaced with, for example, a pyrimidine ring, a pyridine ring, a pyridazine ring, a cyclohexane ring, a dioxoborinane ring, or the like, and may have a halogen group such as fluorine or chlorine. The optically active group is, for example, a 1-methylalkyl group, a 2-fluoroalkyl group,
2-chloroalkyl group, 2-chloro-3-methylalkyl group, 2-trifluoromethylalkyl group, 1-alkoxycarbonylethyl group, 2-alkoxy-1-methylethyl group, 2-alkoxypropyl group, 2-chloro -1
-Methylalkyl group, 2-alkoxycarbonyl-1-
It may be replaced with a trifluoromethylpropyl group or the like. Further, the length of the spacer may be changed within the range of 1 to 30 as long as it exhibits ferroelectricity.

The epoxy-based curable adhesive and acrylic UV-curable adhesive mixed with the ferroelectric polymer liquid crystal may be used alone or in combination of two or more. In addition, the adhesive includes
The epoxy-based thermosetting adhesive contains a curing agent such as an amine and an acid anhydride. The adhesive is suitable for improving the adhesion to the substrate and the strength of the liquid crystal element.

Further, a thermoplastic resin may be mixed and used as the adhesive. When a mixture of the adhesive and the thermoplastic resin is used, the proportion of the adhesive may be 50% by weight or more.

As an example of the epoxy thermosetting adhesive, a bisphenol A type is preferable as the main component. Bisphenol A
It is also possible to use a main agent in which the part of bisphenol compound as shown below is used.

That is, in the above epoxy compound, R ¹ and R ² are methyl groups (bisphenol A type), R ¹ is a methyl group, R ² is an ethyl group, R ¹ is a methyl group, R ² is an isopropyl group, and R ¹ is a methyl group. R ² is an isobutyl group, R ¹ is a methyl group, R ² is a heptyl group, R ¹ is a methyl group, R ² is a nonyl group, R ¹ and R ² are propyl groups, R ¹ and R ² are butylidene groups, respectively. Pentylidene group,
Examples thereof include a 2-methylpentylidene group, a 3-methylpentylidene group, a methyl group of R ¹ and R ^{2 and a} methyl group of X and Y.

As a curing agent for the epoxy compound, diethylenetriamine, triethylenetetramine, xylylenediamine, diaminodiphenylmethane, polyamide resin, dicyandiamide, boron trifluoride-amine complex, triethanolamine borate ester, hexahydrophthalic anhydride, phthalic anhydride, Maleic anhydride, polysulfide, resole and the like can be used. The epoxy thermosetting adhesive may be either a one-component type or a two-component type.

Examples of the epoxy thermosetting adhesive are shown below.

Examples of the acrylic UV-curable adhesive include a mixture of an acrylic ester with a polymerization initiator (which is cured by irradiation with light).

As the thermoplastic resin, one having a Tg of preferably 30 ° C. or higher, more preferably 70 ° C. or higher is used.

Specifically, polyvinyl chloride, polyvinyl bromide, polyvinyl fluoride, vinyl chloride-vinyl acetate copolymer, vinyl chloride-ethylene copolymer, vinyl chloride-propylene copolymer, vinyl chloride-vinylidene chloride copolymer Polymer, vinyl chloride-butadiene copolymer, vinyl chloride-acrylic acid ester copolymer, vinyl chloride-acrylonitrile copolymer, vinyl chloride-styrene-acrylonitrile terpolymer, vinyl chloride-vinylidene chloride-vinyl acetate copolymer Halogenated vinyl polymers or copolymers such as polymer, polyvinylidene chloride, polytetrafluoroethylene, polytetrafluorochloroethylene, polyvinylidene fluoride; unsaturated alcohols such as polyvinyl alcohol, polyallyl alcohol, polyvinyl ether, polyallyl ether Or the weight of ether Polymers or copolymers of unsaturated carboxylic acids such as acrylic acid or methacrylic acid; unsaturated bonds in alcohol residues such as polyvinyl esters such as polyvinyl acetate and polyallyl esters such as polyphthalic acid Polymers or copolymers of those having; polyacrylic acid ester, polymethacrylic acid ester,
Polymers or copolymers of acid residues such as polymers of maleic acid esters or fumaric acid esters or those having unsaturated bonds in acid residues and alcohol residues; Polymers or copolymers of acrylonitrile or methacrylonitrile Unsaturated poly (vinylidene cyanide), malononitrile or fumaronitrile polymers or copolymers; ,
Polymers or copolymers of aromatic vinyl compounds such as styrene-p-methylstyrene copolymer, polyvinylbenzene, and polyhalogenated styrene; and heteropolymers such as polyvinylpyridine, poly-N-vinylpyrrolidine, and poly-N-vinylpyrrolidone Polymer or copolymer of cyclic compound; Polyester condensate such as polycarbonate, polyamide condensate such as nylon 6, nylon 6,6; Polymer or copolymer containing maleic anhydride, fumaric anhydride and its imidized product Polyamide imide, polyether imide, polyimide,
Examples thereof include heat-resistant organic polymers such as polyphenylene oxide, polyphenylene sulfide, polysulfone, polyether sulfone, and polyarylate.

In the present invention, since the thermoplastic resin is used as the structural material, the compatibility with the liquid crystal material may be high or low.

Adhesion between ferroelectric polymer liquid crystal and the above adhesive (epoxy thermosetting adhesive and / or acrylic UV curable adhesive), and ferroelectric polymer liquid crystal when thermoplastic resin is added The agent and the thermoplastic resin may be mixed directly as they are or as a solution using a solvent. The mixing may be carried out at room temperature or may be carried out by heating.

Various solvents such as methylene chloride, chloroform, toluene, xylene, tetrahydrofuran, methyl ethyl ketone, dimethylacetamide, and dimethylformamide can be used as the solvent. By evaporating this solvent, a uniformly dispersed mixture can be obtained, and the size of the liquid crystal capsule can be changed by adjusting the evaporation rate.

The mixing ratio of the ferroelectric polymer liquid crystal, the adhesive and the thermoplastic resin is such that the ratio of the ferroelectric polymer liquid crystal is usually 20 to 97% of the whole.
It is desirable to set the content by weight, preferably 50 to 80% by weight. If the blending ratio of the ferroelectric polymer liquid crystal is too small, the contrast may decrease, and conversely, if it is too large, the mechanical strength of the liquid crystal optical element may be insufficient.

Further, a liquid crystal display dye can be blended in the ferroelectric polymer liquid crystal composition of the present invention. The compounding amount is preferably 0.1 to 3% by weight in the composition.

Liquid crystal display dyes include styryl-based, azomethine-based,
Azo dyes, naphthoquinone dyes, anthroquinone dyes, merocyanine dyes, benzoquinone dyes, and tetrazine dyes are used. Azo type and anthraquinone type are preferable.

Examples of the styryl dye include 4- [β- (6′-nitro-2′-benzothiazolyl) vinyl] -N, N-dimethylaniline.

Examples of the azomethine dye include 2-[(4-dimethylamino) benzylideneamino] benzothiazole.

Examples of the azo dyes include azobenzene, 4-nitroazobenzene, 4-dimethylaminoazobenzene, 4-dimethylamino-2'-methylazobenzene, 4-dimethylamino-2-methyl-4'-nitroazobenzene, and 4-dimethylamino-2-methyl-4'-nitroazobenzene.
Dimethylamino-3-methyl-4'-nitroazobenzene, 4-dimethylamino-2'-chloro-4'-nitroazobenzene, 4-dimethylamino-2 ', 4'-dinitroazobenzene, 4-dimethylamino-2' , 5'-dichloro-4'-nitroazobenzene, 4-dimethylamino-2 ', 6'-dichloro-4'-nitroazobenzene, 4
-Diethylamino-4'-nitroazobenzene, 4-
(5'-Nitro-2'-thiazolylazo) -N, N-dimethylaniline, 4- (6'-ethoxy-2'-benzothiazolylazo) -N, N-dimethylaniline, 4- (6 '
-Nitro-2'-benzothiazolylazo) -N, N-diethylaniline, 9-phenylazourolidine, 4- [N
-(4-Ethoxybenzylideneamino) phenylazo]
-1- [N- (4-ethoxybenzylidene)] naphthylamine, 4-phenylazo-4 '-(1-pyrrolidinyl) azobenzene, 4- (2-benzothiazolylazo)
-4'-N, N-diethylaminoazobenzene, 4- (6
-Ethoxy-2-benzothiazolylazo) -4'-N, N
-Dimethylaminoazobenzene, 4- (6-ethoxy-
2-benzothiazolylazo) -4'-N, N-diethylaminoazobenzene, 4- (6-nitro-2-benzothiazolylazo) -4'-N, N-diethylaminoazobenzene, 4- (6- n-Butylsulfonyl-2-benzothiazolylazo) -4'-N, N-diethylaminoazobenzene, trisazobenzene, 4,4'-bis (2-hydroxy-1-naphthylazo) azobenzene, 4,4'-bis (P-Dimethylaminophenylazo) -2,2'-dichloroazobenzene, 4,4'-bis (9-eurolidinylazo) azobenzene and the like can be mentioned.

As a naphthoquinone dye, 3-butylamino-2
-Cyano-5-amino-8-hydroxy-1,4-naphthoquinone, 3,8-bis (butylamino) -2-cyano-5
-Amino-1,4-naphthoquinone and the like can be mentioned.

Anthraquinone dyes include 1-hydroxy-4
-(4'-methylphenylamino) anthraquinone, 1
-Aminoanthraquinone, 1-amino-4-methylaminoanthraquinone, 1-amino-4-phenylaminoanthraquinone, 1,4-diaminoanthraquinone, 1,4-diaminoanthraquinone- (Nn-butyl) -2,3- Dicarboximide, 1,4-diaminoanthraquinone-
(Nn-hexyl) -2,3-dicarboximide, 1,4
-Diaminoanthraquinone- (Nn-butyl) -3 '
-Imino-2,3-dicarboximide, 1,4-diaminoanthraquinone- (Nn-hexyl) -3'-imino-
2,3-dicarboximide, 1,4-diaminoanthraquinone- (Nn-hexyl) -3'-thioxo-2,3-dicarboximide, 1,4-diaminoanthraquinone-
(Nn-octyl) -3'-thioxo-2,3-dicarboximide, 1,5-diaminoanthraquinone, 1,4,5-
Triaminoanthraquinone, 1,4,5,8-tetraaminoanthraquinone, 1,4-bis (methylamino) anthraquinone, 1,4-bis (phenylamino) anthraquinone,
1,4-bis (4'-t-butylphenylamino) anthraquinone, 1,5-bis (phenylamino) anthraquinone, 1,5-bis (4'-methylphenylamino) anthraquinone, 1,5-bis (4 '-Hydroxyphenylamino) anthraquinone, 1,5-bis (4'-ethylphenylamino) anthraquinone, 1,5-bis (4'-methoxyphenylamino) anthraquinone, 1,5-bis (4'
-N-propylphenylamino) anthraquinone, 1,5
-Bis (4'-isopropylphenylamino) anthraquinone, 1,5-bis (4'-dimethylaminophenylamino) anthraquinone, 1,5-bis (4'-ethoxyphenylamino) anthraquinone, 1,5-bis (4 '-N
-Butylphenylamino) anthraquinone, 1,5-bis (4'-n-propoxyphenylamino) anthraquinone, 1,5-bis (4'-n-pentylphenylamino)
Anthraquinone, 1,5-bis (4'-n-butoxyphenylamino) anthraquinone, 1,5-bis (4'-morpholinophenylaminoanthraquinone, 1,5-bis (4'-n-pentyloxyphenylamino) Anthraquinone, 1,5-bis [4 '-(N-ethyl-N-β-hydroxyphenyl) phenylamino] anthraquinone,
1,5-bis (4'-phenoxyphenylamino) anthraquinone, 1,5-bis (4'-hexyloxyphenylamino) anthraquinone, 1,5-bis [4 '-(phenylazo) phenylamino] anthraquinone, 1, 5-bis (4'-n-heptyloxyphenylamino) anthraquinone, 1,5-bis (4'-n-octyloxyphenylamino) anthraquinone, 1,5-bis (4'-nonyloxyphenylamino) anthraquinone, 1,5-bis (4'-n-decyloxyphenylamino) anthraquinone and the like can be mentioned.

3-Ethyl-5- [4- (3
-Ethyl-2-benzothiazolidene) -2-hexenylidene] rhodamine and the like.

Examples of the benzoquinone dye include 2,5-di (4-heptyloxyphenyl) -3,6-dichlorobenzoquinone.

Examples of the tetrazine dye include 6- (4-pentyloxyphenyl) -3- (4-pentylpiperidin-1-yl) -1,2,4,5-tetrazine and 3- (p-butoxyphenyl) -6-. (4'-n-pentylcyclohexyl)-
6- (4-trans-4'-butylcyclohexylphenyl) -1,2,4,5-tetrazine, 3-n-hexyl-6
Examples include-(4-n-butyloxyphenyl) -1,2,4,5-tetrazine.

〔Example〕

Hereinafter, the present invention will be described in detail based on examples, but the present invention is not limited thereto.

Example 1 Ferroelectric polymer liquid crystal Mn = 5300 Phase transition behavior [Cry: crystalline phase, SmC ^* : chiral smectic C phase, Sm
A: Smectic A phase, Iso: Isotropic phase] 50 parts by weight of the above ferroelectric polymer liquid crystal and epoxy resin (Epicote 834 manufactured by Yuka Shell Epoxy Co. and its curing agent Q
X-11 mixed in a weight ratio of 2: 1) 40 parts by weight and polyvinyl acetate 10 parts by weight to obtain a ferroelectric liquid crystal composition, which is dissolved in dichloromethane to obtain a 15% by weight solution. I chose PES substrate with ITO electrode (thickness 125 μm, width 15 cm,
The above solution was applied to a roll having a length of 50 m) using a microgravure coater, and after evaporation of the solvent, a film having a thickness of about 3 μm was obtained.
Laminate the same type of PES substrate as the opposite substrate,
Orientation treatment was carried out by passing between four rolls as shown in FIG. In the figure, 1, 2, 3, 4 are rolls for bending and orientation treatment having a roll diameter of 80 mm, and 9 is a winding roll. At this time, the line speed v is 3 m / min, T ₁ = 115 ° C, T ₂ = 95 ° C, T
₃ = 90 ° C. and T ₄ = 25 ° C.

After the above alignment treatment, it was left at room temperature for about 1 hour, and after the epoxy resin was almost cured, it was cut into a liquid crystal cell of 15 cm × 30 cm. When the contrast at room temperature was measured under crossed Nicols, a good alignment state of 28 was obtained by applying ± 5 V,
The display remained for more than 24 hours even when the electric field was turned off.

As described above, according to this method, continuous production (coating, laminating, alignment treatment, cutting) of a long product is possible, and a good alignment state can be easily obtained.

In addition, the mechanical strength of the liquid crystal cell was examined. As a result, there was no change in contrast and bistability under a vertical pressure of 10 kg / cm ² and a bending deformation at room temperature up to a radius of curvature of 3 cm. .

Comparative Example 1 For the purpose of Comparative Example, a liquid crystal composition using the following low molecular ferroelectric liquid crystal was used in place of the ferroelectric polymer liquid crystal of Example 1.

Low molecular ferroelectric liquid crystal Phase transition behavior Coating, film formation and lamination were carried out in the same manner as in Example 1.
The line speed v is _{3m / min, T 1 = 56} ℃, T 2 = 50 ℃, T 3 = 45
℃, T ₄ = 25 ℃.

The contrast was 13 (25 ° C) when ± 5V was applied. Next, when the mechanical strength was examined, it was 3 kg / c for vertical pressure.
Bending deformation at m ² and room temperature showed no disordered orientation up to a radius of curvature of 12 cm. However, it was revealed that the mechanical strength of the ferroelectric polymer liquid crystal was considerably reduced as compared with the case of using it.

Example 2 Ferroelectric polymer liquid crystal I Mn = 15000 Phase transition behavior [G: glass state, S ₁ : unidentified smectic phase] Ferroelectric polymer liquid crystal II Mn = 3000 Phase transition behavior A mixture of the above two types of liquid crystal mixed at 50:50 (mol%), a mixture of UV curable acrylic adhesive (Semedine Corp., Semeloc Super Y-862-1) and polyvinyl pyridine (adhesion) Agent and polyvinyl pyridine in a weight ratio of 4:
1) and were mixed in a ratio of 3: 1 to obtain a liquid crystal composition. This ferroelectric liquid crystal composition was dissolved in acetone to prepare a 10 wt% solution.

Then, this solution was uniaxially stretched to form a PET substrate with ITO (thickness
100 μm, width 200 mm, length 20 m) was applied using a direct gravure coater, and then heated to 50 ° C. to evaporate the solvent. At this time, the film thickness of the liquid crystal composition was 2.5 μm. Subsequently, a counter substrate was laminated on this, and a bending orientation treatment was performed with two rolls as shown in FIG. In the figure, 5 is a heating furnace, 6 and 7 are rolls for bending orientation treatment, and 8
Is a 400W metal hydride lamp. Roll diameter 6 is 100mm, 7 is 60mm, line speed v is 4m / min, T ₅
= 130 ° C., T ₆ = 100 ° C., T ₇ = 75 ° C.

Immediately after the above alignment treatment, UV irradiation was performed, and the resin portion was cured and then cut, and then cut into several cm squares and the contrast was measured. At an applied voltage of ± 5 V, it was 47 at 70 ° C and 30 at 25 ° C. was gotten. In addition, the display was retained for 72 hours or more even when the electric field was turned off, indicating good memory performance. Mechanical strength is vertical pressure 15kg / cm ² or more, bending radius 2cm at bending deformation (room temperature)
No decrease in contrast or memory was observed.

Comparative Example 2 The ferroelectric polymer liquid crystal used in Example 1 and the thermoplastic poly-
3-chlorostyrene And were mixed at a weight ratio of 2: 1 to obtain a ferroelectric liquid crystal composition.
Using this, a 2.3 μm film was prepared in the same manner as in Example 1, and using the apparatus shown in FIG. 1, line speed v = 3 m / min, T ₁ =
Alignment treatment was performed at 115 ° C., T ₂ = 95 ° C., T ₃ = 60 ° C., T ₄ = 25 ° C. to obtain a liquid crystal cell. When the contrast at room temperature was measured, a contrast of 26 was obtained by applying ± 5V. Also, when the mechanical strength of the liquid crystal cell was examined, vertical pressure of 7 kg / c
The orientation was not disturbed by deformation up to m ² and a radius of curvature of 5 cm.

〔The invention's effect〕

When the ferroelectric polymer liquid crystal composition of the present invention is used, it is possible to manufacture a liquid crystal optical element having a large area and good film-forming properties.

In addition, a highly aligned liquid crystal optical element can be manufactured extremely easily by a mechanical alignment method such as bending deformation treatment.

When the ferroelectric polymer liquid crystal composition of the present invention is used, a liquid crystal optical element having excellent mechanical stability, bistability, and high-speed response can be obtained.

[Brief description of drawings]

FIG. 1 and FIG. 2 are cross-sectional explanatory views of an apparatus used for bending and orienting a liquid crystal material used in Examples of the present invention.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location G02F 1/137 500 (56) Reference JP-A 63-264629 (JP, A) JP-A 63 -99204 (JP, A) JP 63-109418 (JP, A) JP 63-137211 (JP, A)

Claims (4)

[Claims] 1. At least one ferroelectric polymer liquid crystal 20 to
97% by weight with epoxy thermosetting adhesive and acrylic UV
At least one adhesive selected from curable adhesives 3 to
A ferroelectric liquid crystal composition containing 80% by weight. 2. A ferroelectric polymer liquid crystal having a number average molecular weight of 1,000.
The ferroelectric liquid crystal composition according to claim 1, which is the above. 3. The ferroelectric liquid crystal composition according to claim 1, wherein the ferroelectric polymer liquid crystal is a copolymer. 4. At least one ferroelectric polymer liquid crystal 50 to
The ferroelectric liquid crystal composition according to claim 1, 2 or 3, which comprises 80% by weight and 20 to 50% by weight of an acrylic UV curable adhesive.