JPH01297431A - Method for processing liquid crystal - Google Patents

Abstract

PURPOSE:To provide an uniform liquid crystal-formable thin film having a mono domain and suitable for record display elements by developing a film- formable liquid crystal containing a polymeric liquid crystal compound on the surface of water. CONSTITUTION:A film-formable liquid crystal (preferably one having a transparent point of >=50 deg.C) comprising a liquid crystal (preferably ferromagnetic liquid crystal) containing a polymeric liquid crystal compound (e.g., a main chain type polymeric liquid crystal compound of the formula) preferably in an amount of 50-100% and, as necessary, a non-liquid crystal polymeric compound (e.g., vinyl chloride resin) is dissolved in a solvent (e.g., an aromatic hydrocarbon) and dropped on preferably 10-25 deg.C water preferably at 20-50 deg.C to develop the film-formable liquid crystal on the surface of the water, thereby forming a thin liquid crystal-formable film. The thin film may be stretched for the improvement of the orientation property thereof and also be crosslinked for the improvement of the strength thereof.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for processing liquid crystals.

[Prior Art] In recent years, in contrast to low-molecular-weight liquid crystal compounds widely used in the electronics application field, the use of high-molecular liquid crystal compounds for recording and display elements has been actively developed.

[Problems to be solved by the invention] However, since no method has been found to uniformly align film-forming liquid crystals such as polymer liquid crystals, it is difficult to obtain monodomain alignment films like low-molecular liquid crystals. Have difficulty.

[Means for Solving the Problems] The present inventors have arrived at the present invention as a result of intensive study on a processing method for uniformly aligning a film-forming liquid crystal and obtaining a monodomain oriented film.

That is, the present invention provides a liquid crystal which is characterized in that a liquid crystal containing a polymeric liquid crystal compound and, if necessary, a film-forming liquid crystal comprising a non-liquid crystalline polymer compound are spread on a water surface to form a liquid crystalline film. It is a processing method.

In the present invention, the liquid crystal containing a polymer liquid crystal compound includes a polymer liquid crystal compound and a mixture thereof with a low molecular liquid crystal compound.

Examples of the polymer liquid crystal compound include a main chain type polymer liquid crystal compound, a side chain type polymer liquid crystal compound, and a main chain-side chain composite type polymer liquid crystal compound.

The main chain type polymer liquid crystal compound is a polymer compound in which mesogen is contained in the main chain, and may contain a flexible group (hereinafter referred to as a spacer) if necessary.

Examples of mesogens include those expressed as QX-Ω. Here, as X, CH=CH.

C-C, CH=CH-Co, Co-0, Co-NH.

etc.

Examples of the spacer include C4 to C12 methylene chains, oxyethylene chains, oxypropylene pyrene chains, dimethylsiloxane chains, and the like.

Examples of main chain type polymeric liquid crystal compounds include those having the following structure described in Macromolecule Hemi, Vol. 184, p. 253 (1983).

[-(CH2)++-〇-Q-Co-0-Q-C○-○
Other main chain polymer liquid crystal compounds include poly(γ
-benzylglutamate), cellulose derivatives such as hydroxypropylcellulose can also be used.

A side chain type polymeric liquid crystal compound is one in which a mesogen is included in the side chain, and a spacer may be interposed between the main chain and the mesogen. In addition to those mentioned above, mesogens include those containing a cholesteryl group or a chiral nematic group. Examples of the main chain used in the side chain type polymeric liquid crystal compound include a C--C bond, an Si-0 bond, and the like.

An example of the former is Macromolecule Hemi-17.
Examples include those shown by the following chemical structure described in Vol. 9, p. 2541 (1978).

Examples of the latter include those represented by the following chemical structure described in JP-A-56-79173.

Examples of the main chain-side chain composite polymer liquid crystal compound include those described in Macromolecular Hemi; Rabid Comics, Vol. 7, p. 389 (1986). Specifically, a polymer compound having a unit represented by the formula can be mentioned.

The polymer liquid crystal compound may contain a crosslinkable group, and such groups include groups that cause a reaction triggered by light irradiation, that is, groups that cause photocrosslinking, and other groups (other than photocrosslinking). It can be roughly divided into groups that crosslink by reaction.

Examples of the group that causes a photocrosslinking reaction include a radical polymerizable group, a photodimerizable group, an azide group, and a cationic polymerizable group.

Examples of the radically polymerizable group include an acrylate group, an α-chloroacrylate group, a methacrylate group, a styryl group, a vinyl group, a vinyl ester group, a vinyl ketone group, and an acrylamide group.

Examples of polymeric liquid crystal compounds containing such radically polymerizable groups include Molecular Crystals & Liquid.
Acrylic ester of hydroxybrobyl cellulose described in Crystals; Letters Vol. 102, p. 255 (1984) and Japanese Patent Application No. 62-294657 7M [I
Examples include polysiloxanes containing an acrylic group as described in I4.

Examples of groups that cause other photocrosslinking reactions and groups that cause crosslinking by other reactions include Japanese Patent Application No. 62-297
Examples include those described in No. 1657.

Preferred crosslinkable groups are photocrosslinkable groups,
Particularly preferred are acrylate and methacrylate-I groups.

Examples of low-molecular liquid crystal compounds include phenylbenzoic acid esters, biphenyl and its esters, phenylcyclohexane and its esters, cyclohexylcyclohegizan and its esters, phenyldioxane and its esters, Examples include phenylpyrimidine and its esters.

Further, in the present invention, the liquid crystal containing a polymer liquid crystal compound may be a ferroelectric liquid crystal, and such a liquid crystal may be a low molecular compound containing a chiral alkyl group, specifically, a low molecular compound containing a chiral alkyl group, specifically, a liquid crystal containing a high-molecular liquid crystal compound, such as a ferroelectric liquid crystal containing a high-molecular liquid crystal compound. The materials described in Chapter 7 of "Liquid Crystal Basics" (Baifukan, published in 1985) can be used.

It is also possible to use tolans containing a 4-ralalkyl group (for example, as disclosed in Japanese Patent Application No. 61-43696). Furthermore, it is also possible to use a ferroelectric polymeric liquid crystal compound as shown in the following formula.

H3 The film-forming liquid crystal includes (1) a liquid crystal containing a polymer liquid crystal compound, and (2) a mixture of a liquid crystal containing a polymer liquid crystal compound and a non-liquid crystal polymer compound.

There are no particular limitations on the non-liquid crystalline polymer compound as long as it is compatible with the liquid crystal compound. Specifically, in addition to vinyl chloride resins, acrylic resins, methacrylic resins, vinyl resins such as styrene resins, and copolymers such as vinyl chloride-acrylic copolymers, polyester IJ resins, Examples include polycarbonate resin and polyurethane resin.

Is a non-liquid crystal polymer compound a polymer? Similar to α compound,
It may also contain a crosslinkable group. Examples of the crosslinkable group include the same groups as those described for the polymeric liquid crystal compound, and preferred ones are also the same.

The crosslinkable group may be included in either the main chain or the side chain of the non-liquid crystalline polymer compound.

As the non-liquid crystalline polymer compound containing such a crosslinkable group, various polymer compounds that are practically used as photocurable resins can be used. Specific examples include triacrylate of triol obtained by addition polymerizing many moles of propylene oxide to glycerin.

The non-liquid crystal polymer compound usually has film-forming properties, but it does not necessarily have to be film-forming as long as the liquid crystal is film-forming.

In the present invention, the intermediate phase taken by the film-forming liquid crystal includes a smectic phase (smectic A phase, chiral smectic C phase, etc.), a nematic phase, a cholesteric phase, and the like. , irral smectic C phase is preferred.

In the present invention, the temperature at which the film-forming liquid crystal transitions from the liquid crystal phase to the isotropic liquid, that is, the clearing point, is usually above O'C,
Preferably it is 50°C or higher.

Various auxiliary agents as described below can be added to the film-forming liquid crystal in advance, if necessary.

Examples of photoinitiators for photocrosslinking include the compounds described in "Photo/Radiation Curing Technology" (Taiseisha, 1985), p. 12, such as acetate phenone, benzophenone, Michler's ketone, benzyl, benzoin, and benzoin ether. , benzyl ether, benzyl dimethyl ketal, thioxanthone and derivatives thereof.

The film-forming liquid crystal may contain a dichroic dye if necessary for displaying or reading out the information in the liquid crystal. Examples of dichroic pigments include merocyanine pigments, anthraquinone pigments, azo, 2g, styryl cysts, azomethine pigments, and squalirium cysts.

The film-forming liquid crystal can contain a light-absorbing dye, which can be selected depending on the wavelength of the recording light.

When using a semiconductor laser, it is preferable to use a near-infrared absorbing dye, and when using a He--Ne laser, Ar laser, tungsten lamp, halogen lamp, etc., it is preferable to use a visible light-absorbing dye.

Various near-infrared absorbing dyes have been developed in recent years, such as those described in Organic Synthetic Chemistry, Vol. 43, No. 4, pp. 36-45 (1985), such as phthalocyanines, TeI-rabhydrocholine, and benzenedithiol nickel complexes. , naph I, quinones, etc. are fried.

Further, the film-forming liquid crystal can contain a non-liquid crystal liquid in order to shorten the response time or lower the driving threshold voltage. Such substances include 2-oxazolidinones,
Examples include propylene carbonate, dialkyl bisfukenols, and alkylcyclohexylcyclohexanes.

In the present invention, an example of the formulation of the film-forming liquid crystal is as follows. % is weight 'B1%.

LCD 30-100% 50-95
% (Polymer liquid crystal compound) 30-10050-95 (Low-molecular liquid crystal compound) 0-700-/1.0 Non-liquid crystal polymer compound 0-70 0-7° (When using a polymer liquid crystal compound) 0- 50 0-30 (If no polymeric liquid crystal compound is used) 0-70 40-70 Photoinitiator 0-30 0-2 Dichroic dye 0-10 0-5 Recording light absorption color base 0-20 1-10 Non liquid crystal liquid
0 to 20 0 to 10 Among the liquid crystals, the amount of high molecular liquid crystal compound is usually 0 to 100%, preferably 50% based on the total weight of the high molecular liquid crystal compound and low molecular liquid crystal compound.
-100%.

In the present invention, the film-forming liquid crystal is processed by spreading its solution on the water surface.

As the solvent used in the present invention, various solvents can be used as long as they are compatible with the film-forming liquid crystal and have low solubility in water. Examples of such compounds include fractional group hydrocarbons, halogenated hydrocarbons, carbons, esters, ethers, and the like.

Additives such as alcohols, phenols, etc. can also be added to these solvents in order to improve the ductility of the water surface film.

A method for spreading the film-forming liquid crystal on a water surface includes a method of dropping the solution onto the water surface. When the solution is added dropwise,
It immediately spreads on the water surface and forms a thin film.

When the solution of the film-forming liquid crystal is brought to a boil, it is desirable to maintain the temperature of the film-forming liquid crystal and the temperature of the water within a certain range in advance. The temperature of the solution is typically 20-50°C. temperature is 2
If it is lower than 0°C, the viscosity will increase and it will be difficult to spread it uniformly.
If the temperature is higher than °C, the solvent will easily volatilize and wrinkles will easily form when spread on the water surface. On the other hand, the temperature of the water is preferably 5
-30°C5, particularly preferably 10-25°C.

If the temperature is lower than 5 °C, the viscosity of the solution increases and
If the temperature is higher than °C, the solvent will easily volatilize.

The thickness of the film formed by casting and drying on the water surface is usually
0.0l-57-on. By using a film-forming liquid crystal with a large molecular weight at a low concentration, an extremely thin film of about 0.1 μm can be easily created. It is also possible to make relatively thick films using high-quality solutions.

Several to hundreds of water surface glabellar membranes can be stacked and used depending on the purpose of application. By doing so, a uniform and relatively thick film having a thickness of about 0.1 to 1001 t to 1'lj· can be obtained.

The water surface film thus obtained can be stretched or crosslinked if necessary.

As the stretching method, a uniaxial stretching method, a biaxial stretching method, an inflated silicon method, etc., which are used for ordinary polymer compounds, can be used.

When stretching, it is possible to stretch in an atmosphere containing vapor of a solvent (for example, toluene, cucorbenzene).

The stretching ratio is usually 50 to 500%, preferably 100 to 500%.
It is 300%.

The stretching speed is usually 10-1000%/min.

The thin film developed on the water surface and stretched if necessary is not self-supporting by itself, so a support is usually required. The support has thermal conductivity, mechanical strength,
Select by considering optical properties, flatness accuracy, etc. Supports include glass, ceramics, plastics,
(acrylic resin/methacrylic resin, polycarbonate resin, polyolefin resin), metal (aluminum, etc.)
Commonly used substrates include:

The shape of the base body can be obtained in various ways depending on the purpose, for example,
Examples include plate shape, disk (circular) shape, and drum shape.

When laminating on a substrate, an adhesive, an adhesive, or the like may be used to improve the adhesion between the film-forming liquid crystal and the substrate. As such, it is possible to use pressure-sensitive adhesives and adhesives commonly used for laminated films.

In the present invention, crosslinking can be carried out if necessary. Preferably, crosslinking is carried out using light.

As this light, ultraviolet rays are usually used, but radiation such as electron beams and alpha rays may also be irradiated.

Both stretching and crosslinking can be carried out, but
Either one may be used.

In addition to the recording/displaying layer made of the liquid crystal film formed on the substrate in this way, layers having various functions for the purpose of recording/displaying can be provided. Examples of such a layer include a light absorbing layer, a reflective layer, an antireflection layer, and a protective layer.

The light-absorbing layer may be formed by coating the above-mentioned light-absorbing pigment, or may be formed by vacuum deposition of carbon or metal (such as bismuth or tellurium). The reflective layer is usually provided by vacuum-depositing aluminum, silver, or the like.

Anti-reflection F? :! ! A transparent inorganic compound such as magnesium fluoride described in Js R Membrane Handbook, page 820 (1981, Ohmsha) can be installed by vapor deposition or other means.

The film-forming liquid crystal obtained according to the processing method of the present invention can be used as a recording display element.

Preferably the element is capable of recording using light.

As recording light, semiconductor laser, Ar laser, He −
Recording light such as a Ne laser is used.

Generally, the laser beam irradiation method is 0.7-107L+
One example is a method of irradiating a beam focused to nφ with a pulse width of 0.1 to 10 μs and an energy of 5 to 2 On+W.

The εΦ light of this element may also include ordinary light sources such as tungsten lamps, xenon lamps, high-pressure mercury lamps,
It is also possible to use light sources from light emitting diodes. When using such a light source, a pattern can be placed and written between the light source and the element. It is also possible to use an arrayed device such as a liquid crystal printer or a light emitting diode printer.

It is also possible to use a heat source such as a thermal printer head instead of light for recording.

Reading is generally performed using an optical head.

Further, the film-forming liquid crystal obtained according to the processing method of the present invention can be used as a large-area display device, and in this case 1, illumination by a backlight can be provided from the rear side if necessary.

Erasing can be done by heat or light. If it is caused by heat, use an infrared lamp, nichrome wire heater, etc.
The recording layer is usually heated to 100 to 150°C.

In the case of erasing with light, the same laser light used for recording can be used.

Recording and erasing can be performed repeatedly, for example, 10 to 100 times or more.

[Example] Hereinafter, the present invention will be further explained with reference to Examples, but the present invention is not limited thereto.

Example 1 A water surface film was formed from a solution of a film-forming liquid crystal containing a polymeric liquid crystal compound, and the structure of the liquid crystal was investigated.

10-Undecenoic acid was reduced with lithium aluminum hydride to give 10-undecenyl alcohol, and 4-toluenesulfonic acid chloride was reacted to give tosyl ester. This was reacted with 4-oxybenzoic acid to etherify it, and then esterified with 4-cyanophenol to form 4-(10-undecenyloxy)-oxybenzoic acid (
CNSO-11) was obtained. Next, this was added to polymethylhydrosiloxane (polymerization degree 40, manufactured by Shin-Etsu Chemical Co., Ltd.) using chloroplatinic acid as a catalyst to form a polymeric liquid crystal compound CN5.
Obtained O-11-40.

Polarized light microscopy (POM), differential scanning calorimetry (DSC)
Accordingly, CN5O-11 has a melting point of 75℃, is non-liquid crystalline, and C
It was found that N5O-11-40 is a liquid crystal with a glass transition point of 15°C and a clearing point of 185°C.

Dissolve 1% CN5O-11-40 in toluene, drop the film-forming liquid crystal solution gently on the wall of the water surface in an aquarium, form a thin film on the water surface, scoop it up, and dry it under vacuum at room temperature to obtain a water surface-spreading film. Ta. After laminating 100 sheets of the membrane thus obtained on a Teflon plate, the membrane was fixed to a frame and then peeled off from the Teflon plate to prepare a composite membrane.

When the film thus prepared was observed with a POM, it was found to be a uniform liquid crystalline film with no defects.

Example 2 Optically active 4-n-decyloxy-4'-(
2-Methylbutyloxycarbonyl)-diphenylacetylene was synthesized by the method described in the specification of JP-A-62-228043, and the mixture with CN5O-11-/10 was dissolved in toluene to form a water surface film. I got it. This film was a uniform liquid crystal film throughout. It was confirmed by the triangular wave method that it had spontaneous polarization.

Example 3 4-allyloxybenzoic acid-4-cyanophenyl ester (CNSO-3) was synthesized as in Example 1,
This and Bo-rimethylhydrosiloxane (degree of polymerization 240)
Therefore, CN5O-11-40 of Example 1 is a polymeric liquid crystal compound CN5 having a different length of methylene spacer and degree of polymerization.
Obtained O-3-240. This was spread out on the water surface in the same manner as in Example 1, and 40 sheets were stacked. Next, this film was stretched 200% at a stretching speed of 250%/min in an atmosphere of 45°C. When the properties of the liquid crystal of the thus obtained film were examined in the same manner as in Example 1, it was confirmed that the degree of orientation was significantly improved compared to before stretching.

Example 4 In order to synthesize a photocrosslinkable polymeric liquid crystal compound, first 4-
Allyloxybenzoic acid trityl ester was obtained by reacting trityl chloride and 4-allyloxybenzoic acid in THF-triethylamine. This trityl ester 0.
84 g of CN5O-32,233 and 0.6 g of polymethylhydrosiloxane (degree of polymerization 120) was treated with water/acetic acid to remove the trityl group.・Next, a photolinkable polymeric liquid crystal compound containing about 20 mol % of acrylate groups based on mesogenic groups was obtained by subjecting I.trifluoroacetic anhydride and hydroxyethyl acrylate to a Jl [ff order reaction.

Separately synthesized 4-(n-octyloxy)-benzoic acid-4
A mixture of 30% cyanophenyl ester and 0.5% photoinitiator Irganox 184 (manufactured by Ciba Geigy) was spread on the water surface in the same manner as in Example 1, and the laminated film was exposed to an ultraviolet irradiation device (Ushioni). Ultraviolet light (1, OJ/cm2) was irradiated using an ultraviolet light (1, OJ/cm2) manufactured by Chic Co., Ltd.).

The film of the crosslinked polymeric liquid crystal compound thus obtained was uniform throughout and had a high degree of orientation.

[Effect of the invention] The liquid crystal processing method of the present invention has the following effects.

(1) A uniform, monodomain alignment film, which has been difficult to obtain in film-forming liquid crystals, can be obtained by the water surface glabella method of the present invention.

In the case of low-molecular liquid crystal compounds, such as nematic liquid crystals, a monodomain liquid crystal film can be obtained by slowly cooling them on an alignment film from a temperature above the clearing point, but in the case of high-molecular liquid crystal compounds, the presence of main chains and Due to the high viscosity, this method resulted in insufficient orientation and only a polydomain film.

(2) In the processing method of the present invention, the response time is significantly shortened by compounding with a ferroelectric liquid crystal compound.

(3) By stretching, a more oriented liquid crystal film can be obtained.

(4) By crosslinking, the oriented state can be fixed and a strong film can be obtained.

Because of the above effects, the processing method of the present invention can be applied to recording and display elements.

Claims (1)

[Claims] 1. A film-forming liquid crystal comprising a liquid crystal containing a polymer liquid crystal compound and, if necessary, a non-liquid crystal polymer compound, is spread on the water surface to form a liquid crystal thin film. Liquid crystal processing method. 2. The processing method according to claim 1, wherein the liquid crystal containing the polymeric liquid crystal compound is a ferroelectric liquid crystal. 3. Claim 1 in which the film-forming liquid crystal has a clearing point of 50°C or higher.
Or the processing method described in 2. 4. The processing method according to any one of claims 1 to 3, wherein the film obtained by spreading the film-forming liquid crystal on the water surface is stretched, if necessary. 5. The processing method according to any one of claims 1 to 4, wherein the film obtained by spreading the film-forming liquid crystal on the water surface is crosslinked, if necessary.