JPH02214731A - Polymeric oriented film substrate - Google Patents

Abstract

PURPOSE:To obtain the title substrate suitable for liquid crystal displays etc., by forming monomolecular solid films (LB film) consisting of a specific fumaric diester polymer on a substrate. CONSTITUTION:The objective substrate made up of (A) a substrate and (B) monomolecular solid films (Langmuir-Blodgett film) built up on the substrate, consisting of a fumaric diester polymer containing >=60mol% of fumaric diester recurring unit of the formula [R1 and R2 are each 3-12C (substituted) branched alkyl, (substituted) 3-12C cycloalkyl, etc.].

Description

[Detailed Description of the Invention] <Industrial Field> The present invention relates to a polymer alignment film substrate, and more specifically, a monomolecular solid film (LB film) of a fumaric acid diester polymer is accumulated on a substrate. The present invention relates to a polymer alignment film substrate.

Since the LB film in which molecules are highly oriented is accumulated on the polymer alignment film substrate of the present invention, for example, if liquid crystal molecules are arranged regularly on the LB film.

A liquid crystal display element is obtained.

<Prior art> As a display method, the liquid crystal method uses little electrical energy and can provide displays with relatively fast response, and can be used for displays ranging from small to large areas.

Since it is possible, it has developed greatly in recent years.

When manufacturing liquid crystal display devices, the key is how regularly the liquid crystal molecules are arranged.
For this purpose, it is important to impart orientation to the liquid crystal substrate.
Various orientation treatment methods are known.

Examples of methods for aligning the substrate include solution coating,
Plasma treatment, rubbing, vapor deposition, pull-up coating @ ("Latest technology of liquid crystals - physical properties, materials, applications" Matsumoto Osamu - 2 co-authored by Ichiyoshi Tsunoda), etc. are known. Among the above methods, the rubbing method is the most common. In this method, the substrate itself is rubbed in a certain direction, or a film of inorganic or organic matter is formed on the surface of the substrate and then rubbed, and the liquid crystal molecules are rubbed in the direction of the rubbing. Arrange in parallel. Currently, the method commonly used at manufacturing sites for liquid crystal cells is to apply polyimide resin to the liquid crystal substrate, and then
This method of rubbing the film is a very excellent method for processing the parallel alignment of liquid crystal molecules.

<Problem to be solved by the invention> In the future, liquid crystal displays with higher contrast and faster response will be desired, but in order to achieve this, the alignment film itself must be made ultra-thin and controlled in on-gest long order. It is necessary. It is also important to control the orientation more precisely. For these purposes, it is difficult to reduce the resin film thickness with the current method of coating polyimide resin and then rubbing it to create an alignment film. cannot be controlled.

On the other hand, a monomolecular film of a low-molecular compound having hydrophilic and hydrophobic groups is formed on the water surface, and pressure is applied to this to form a solid film (L
B film) and use an ultra-thin film obtained by accumulating this on a liquid crystal substrate, or a method of similarly accumulating monopolymerizable low molecular weight compounds and polymerizing the LB film (Japanese Patent Laid-Open No. 63-27445
No. 1) etc. have been proposed. However, low-molecular LBH has insufficient chemical, thermal, and mechanical resistance and is therefore impractical, and polymerizable LB films are not preferred because defects occur due to shrinkage during polymerization.

It is desired to develop a molecular alignment film substrate that has excellent liquid crystal orientation, excellent mechanical, chemical and thermal durability, and can be made into an ultra-thin film. Development of materials and technologies suitable for these purposes is required. is still not enough.

<Means for Solving the Problems> According to the present invention, there is provided a substrate and diene fumarate accumulated on the substrate. A polymer alignment film substrate comprising a monomolecular solid film (Langmuir-Blodgett film, LB film) of a chilled polymer, wherein the fumaric acid diester polymer has a substituent having a structure derived from the following general formula. It represents a substituted cycloalkyl group or a siloxane hydrocarbon group having 3 to 1 o carbon atoms, and the branched alkyl group, the cycloalkyl group, the substituted alkyl group, the substituted cycloalkyl group, and the siloxane hydrocarbon group include May contain heteroatoms,
Further, there is provided a polymer alignment film substrate characterized by containing at least 60 mol % or more of a repeating unit of a fumaric acid diester represented by ), which may be substituted with a halogen atom.

The present invention will be explained in more detail below.

In the present invention, the following general formula (wherein R1 and R8 represent the same or different groups, and at least one group of R1 and R8 has 3 to 12 carbon atoms)
A branched alkyl group having 3 to 12 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, and 2 carbon atoms having a substituent having a ring structure having 3 to 14 carbon atoms.
~6 substituted alkyl groups, using a fumaric acid diester polymer containing the repeating unit of the fumaric acid diester shown above. In the formula 0, R1 and R2 represent the same or different groups, and at least one of R1 and R2 The group has 3 carbon atoms
-12 branched alkyl group, cycloalkyl group having 3 to 12 carbon atoms, substituted alkyl group having 2 to 6 carbon atoms having a substituent having a ring structure having 3 to 14 carbon atoms, having a substituent having the above ring structure Represents a substituted cycloalkyl group or siloxane hydrocarbon group having 3 to 10 carbon atoms: The branched alkyl group, the cycloalkyl group, the substituted alkyl group, the substituted cycloalkyl group, and the siloxane hydrocarbon group contain a nitrogen atom. ,
When only one of R□ and R2 is the above hydrocarbon group, which may contain a heteroatom such as an oxygen atom, a phosphorus atom, or a sulfur atom, and may be substituted with a halogen atom, the other The group is preferably an alkyl group having 1 to 12 carbon atoms or a cycloalkyl group having 3 to 12 carbon atoms.

Examples of the above-mentioned fumaric acid diesters having a hydrocarbon group include diisopropyl fumarate and di-tart-fumaric acid.
Butyl, dicyclohexyl fumarate, di-5e fumarate
c-butyl, di-4-methyl-2-pentyl fumarate,
Isopropyl-tert-butyl fumarate, Isopropyl-isoamyl fumarate, Isopropyl-4-fumarate
Methyl-2-pentyl, isopropyl-2-ethylhexyl fumarate, isopropyl-nonyl fumarate.

tert-butyl-5ea-butyl fumarate, tert-butyl-isoamyl fumarate, tar fumarate
t-Butyl-4-methyl-2-pentyl, te fumarate
Preferred examples include rt-butyl-2-ethylhexyl. Further, fumaric acid diesters having a siloxane hydrocarbon group include methyl-(trimethylsilyl)-fumarate, ethyl-(trimethylsilyl)-
fumarate, isopropyl-(trimethylsilyl)-fumarate, cyclohexyl(trimethylsilyl)-fumarate, tart-butyl-(trimethylsilyl)-fumarate, isopropyl-[3-tris(trimethylsiloxy)silyl]propyl fumarate, isopropyl-3-(( Examples of fumaric diesters containing heteroatoms include N,N-dimethylaminoethyl-isopropyl fumarate, tart-butyl-1-butoxy-2- Propyl fumarate, 2-cyanoethyl-isopropyl fumarate, glycidyl-isopropyl fumarate.

Diethylphosphonomethyl-isopropyl fumarate, 2
-Methylthioethyl-isopropyl fumarate and the like. On the other hand, examples of fumaric acid diesters substituted with halogen atoms include perfluorooctylethyl-isopropyl fumarate, triple olomethyl-isopropyl fumarate, and pentafluoroethyl-isopropyl fumarate.
Examples include isopropyl fumarate, hexafluoro-isopropyl fumarate, and bis-1-chloro-isopropyl fumarate.

In the present invention, a fumaric acid diester polymer obtained by polymerizing fumaric acid diester is used. To obtain the fumaric acid diester polymer, it is preferable to use an ordinary radical polymerization method.As the polymerization initiator used in the polymerization, organic peroxides and azo compounds having a 10-hour half-life temperature of 120°C or less are used. One or more types may be used.

As a polymerization initiator, benzoyl peroxide, diisopropyl peroxycarbonate, tert-butyl peroxy-2-ethylhexanoate, tart-butyl peroxy bivalate, tert-butyl peroxy diisobutyrate, lauroyl peroxide, azobisisobutyroyl peroxide, The amount of the polymerization initiator such as nitrile used is preferably 10 parts by weight or less, more preferably 5 parts by weight or less, based on 100 parts by weight of the raw material monomer.

The fumaric acid diester polymer used in the present invention must contain at least 60 mol % or more of fumaric acid diester repeating units. This means that the content of fumaric acid diester units in the fumaric acid diester polymer used in the present invention is 60.
This is because if the amount exceeds mol%, the fumaric acid diester polymer becomes rigid due to the side chains and the molecular form becomes rod-like, so that it does not form a thread-like aggregate.

In the present invention, when forming a monomolecular solid film of a fumaric acid diester polymer (usually referred to as a Langmuir-Blodget film or LB film), the fumaric acid diester polymer is treated with a vaporizable organic solvent that is immiscible with water. A fumaric acid diester solution is obtained by dissolving the fumaric acid diester solution, and then the fumaric acid diester solution is spread on a clean water surface to form a gas film. As the transpirationable organic solvent, general-purpose organic solvents such as chloroform, ethylene dichloride, benzene, toluene, etc. can be mentioned, and the fumaric acid diester polymer is made into a dilute solution of these organic solvents and gently spread on a horizontal surface. do. When spreading on a horizontal surface, it is necessary to pay attention to the concentration of the fumaric acid diester polymer solution and the type of solvent. If a concentrated solution or a solvent that is miscible with water is used, a mere water surface spread film is likely to result. , it is not possible to control the molecular orientation, surface smoothness, homogeneity, etc. of the film, and it is also impossible to prepare an ultra-thin film, and the concentration of the solution to be developed is 10
■/■Ω or less is desirable, preferably 0.1~
It is in the range of 3■/m II. The selection of the type and concentration of the solvent needs to vary slightly depending on the working temperature; the higher the temperature, the more preferable it is to use a high-boiling point solvent such as benzene or ethylene dichloride, and the more dilute the solution is, however, at normal working temperatures. , concentration 10■/■Ω in the range of 10 to 35℃
The following conditions are sufficient. When it is spread on the water surface and the solvent is evaporated, a gas film is obtained in which the molecules do not interact with each other and the surface pressure is usually less than 1 dy16/ffi.

The gas film obtained as described above becomes a solid film by applying surface pressure from the horizontal direction and maintaining it at about 3 to 3 Qdyne/cs. How much surface pressure to set depends on the type of fumaric acid diester polymer used. Obtain the surface pressure-area (FA) isotherm curve in advance, and find the sharp rising part of the FA curve that corresponds to the solid film phase. Set the surface pressure to .

Next, a polymer alignment film substrate is obtained by depositing this solid film on a substrate by a vertical dipping method or a horizontal deposition method.

Various commonly used substrates can be used as the substrate on which the above-mentioned LB film is accumulated, but in order to make a cell for a liquid crystal display, it is necessary to use a conductive transparent substrate. A material 1 made of glass imparted with conductivity, such as an ITO (indium oxide) glass substrate, a NESA (tin oxide) glass substrate, etc., is used. In addition, various transparent resins with conductivity can be used, but in order to accumulate the polymer LB film, it is desirable to use a conductive glass substrate from the viewpoint of surface smoothness, scratch resistance, etc. .

<Effects of the Invention> Since the polymer alignment film substrate of the present invention uses an LB film of fumaric acid diester polymer, it has a smooth film surface without film defects such as pinholes, and has a high degree of orientation. This makes it an excellent material for electrical devices such as liquid crystal display devices.

<Examples> Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited by these.

Pure water was poured into a Teflon trough with an inner area of 20 x 20 cm and a depth of 103 cm to a depth of 83 cm, and the temperature of the entire room was set at 20°C. 150 μg of a chloroform solution of poly(diisopropyl fumarate) (abbreviated as PDiPF) with a concentration of 1 / ■ Ω was gently dropped onto the water surface, and the solution was placed on the water surface while detecting the surface pressure that caused the solvent to evaporate. The length is 20C! The Teflon float of No. 1 is moved in parallel at a speed of 2 dyna/n to narrow the surface area and increase the surface pressure by 5 dyna/n.
am, an LB film was prepared, and five layers were accumulated on an ITO glass substrate by a vertical dipping method to prepare a polymer alignment film substrate.

A liquid crystal cell 10 as shown in the attached drawings was created using the obtained polymer alignment film substrate. That is, the polymer alignment film substrate 1 of the present invention is obtained by accumulating the LB film 13 on an ITO glass substrate consisting of a glass substrate 12 covered with an ITO film 11.
A TN (twisted nematic) alignment type liquid crystal cell 10 is made by stacking two sheets of 4 with their orientations perpendicular to each other and sealing a liquid crystal 15 (p-methoxybenzylidene-p'-butylaniline (MBBA)) between them. 16, the electrical response was examined by visual observation using a polarizing plate and by applying a voltage. As a result, it was found that the response to electricity was good. On the other hand, as a result of photographing the polymer alignment film substrate 14 using a differential interference optical microscope at a magnification of 400 times and enlarging it to a magnification of 1000 times, no defects in the film that would affect the orientation were observed. was found to be uniformly created.

Similarly, LB films were created by varying the surface pressure in the range of 5 to 25 dyne/Ql, and various polymer alignment film substrates were created by accumulating 5 to 20 layers, and the resulting polymer alignment film substrates were A liquid crystal cell 10 was created using the same. When the electrical response was investigated in the same way, the surface pressure was 5 to 15 dyne.
It has been found that the liquid crystals accumulate at a relatively low layer of about 5/am before forming a complete solid film, and that a cumulative number of about 5 layers is enough to orient the liquid crystal and provide good electrical response.

Poly(fumaric acid di-t) was used instead of PDiPF in Example 1.
-Butyl) (abbreviated as PDtBF) (abbreviated as PDtBF) in the same manner as in Example 1 except that a 1■/■a chloroform solution was used.
A liquid crystal cell 10 was prepared using a polymer alignment film substrate 14 in which four LB films (surface pressure 8 dyne/cm) were stacked, and the alignment and electrical response of the liquid crystal 15 were examined. As a result, it was found that the liquid crystal 15 had good alignment and good responsiveness to electricity.

Table 3311 P D c in the same manner as in Example 1 except that a li@/mQ chloroform solution of poly(dicyclohexyl fumarate) (PDcHF) was used instead of PDiPF in Example 1.
A liquid crystal cell 10 was prepared using a polymer alignment film substrate 14 in which six HF LB films were accumulated, and the alignment and electrical response of the liquid crystal 15 were examined. As a result, it was found that the liquid crystal 15 had good alignment and good responsiveness to electricity.

Poly(fumaric acid di-8) was used instead of PDiPF in Example 1.
(3Q-Butyl) (PDsBF, Example 4).

Poly(di-4-methyl-2-pentyl fumarate) (PD
MPF, Example 5), poly(tert-butyl-5ea-butyl fumarate) (PtB/sBF.

Example 6), poly(tert-butylisoamyl fumarate) (PtB/iAmF, Example 7).

Poly(tert-butyl-4-methyl-2-pentyl fumarate) (PtB/MPF, Example 8), Poly(tert-butyl-2-ethylhexyl fumarate) (PtB/
EHF, Example 9), poly(isopropyl fumarate-perfluorooctylethyl) (Pip/FxvFt Example 10), poly(isopropyl fumarate-hexafluoroisopropyl) (PiP/1P-F, F, Example 11)
), poly(2-chloroisopropyl fumarate) (P
DCliPF, Example 12), poly(N,N-dimethylaminoethyl-isoprobyl fumarate) (PAESP
F, Example 13), poly(1-butoxy-2-propyl-tart-butyl fumarate) (PBPtBF, Example 14), poly[isopropyl-(3-tris(trimethylsiloxy)silyl)propyl fumarate) ( PSi
iPF.

Example 15) was carried out in the same manner as in Example 1 except that the polymer alignment film substrate 1 was prepared using the surface pressure and calendar number shown in Table 1.
4, a prototype liquid crystal cell 10 was manufactured, and the orientation and electrical response of the liquid crystal were investigated. As a result, it was found that all of the polymer alignment film substrates 14 had good alignment of the liquid crystal 15 and good responsiveness to electricity. In addition, Table 1 also shows Example 1 table.

[Brief explanation of the drawing]

The accompanying drawing is a schematic perspective view schematically showing the outline of a liquid crystal cell prepared using a polymer alignment film substrate according to the present invention. In the figure, 10...Liquid crystal cell, 11...ITO film, 12...
Glass substrate, 13...LB film, 14...polymer alignment film substrate, 15...liquid crystal. 1゜2゜3゜Indication of the case 1999 Patent Application No. 32865 Name of the invention Person who corrects polymer alignment film substrate Relationship to the case Patent issuer (434) Nippon Oil Co., Ltd. 4, Agent Address: 1-20 Toranomon, Minato-ku, Tokyo 105 5゜6゜ Drawings subject to correction Details of the correction as per attached sheet

Claims (1)

[Scope of Claims] A polymer alignment film substrate comprising a substrate and a monomolecular solid film of fumaric acid diester polymer (Langmuir-Blodgett film, LB film) accumulated on the substrate, The fumaric acid diester polymer has the following general formula ▲ Numerical formula, chemical formula, table, etc. Branched alkyl group, cycloalkyl group having 3 to 12 carbon atoms, substituted alkyl group having 2 to 6 carbon atoms having a substituent having a ring structure having 3 to 14 carbon atoms, and having a substituent having a ring structure having 3 to 3 carbon atoms ~10 substituted cycloalkyl groups or siloxane-based hydrocarbon groups, the branched alkyl group,
The cycloalkyl group, the substituted alkyl group, the substituted cycloalkyl group, and the siloxane-based hydrocarbon group may contain a heteroatom or may be substituted with a halogen atom. ) A polymer alignment film substrate containing at least 60 mol % or more of a repeating unit of a fumaric acid diester shown in (a).