JPS6270407A - Preparation of orientated film - Google Patents

Abstract

PURPOSE:To obtain an uniaxially orientated film free of strain and excellent in optical transparency, by supporting a specified liquid crystal monomer and a photopolymerization initiator-containing composition on a support subjected to orientation treatment and irradiating the monomer in a state of a liquid crystal with ultraviolet rays or visible light. CONSTITUTION:At least two liquid crystal monomers which show a nematic or smectic phase and have a polymerizable functional groups in the molecule [e.g., formula I (wherein R is H or CH3, n is 1-8 or 11, X is formula II, III or the like and Z is -CN, -F or the like) and a composition containing a photopolymerization initiator (e.g., formula IV), if desired, after the addition of a dichroic dye, an ultraviolet absorber and a gapping agent (e.g., glass beads) is polymerized by irradiation with ultraviolet rays or visible light, while the monomers are kept in a state of a liquid crystal.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention] The present invention relates to a method g1 for producing a film with uniaxial C, two degrees of g, and two orientations. Films with a high degree of knee axis orientation have a strong mechanical strength in the direction of orientation, and are used not only for packaging films that take advantage of this strength, but also for reinforced films laminated at right angles to each other. Utilizing the optical anisotropy in the perpendicular direction, it can be used in retardation films, fully doped with dichroic dyes, used in polarizing films, and other optical filters, optical switching elements, recording materials, or displays. It is also used as a material.

[Conventional technology]

Highly uniaxially oriented membranes have traditionally been melt extruded or solution cast, uniaxially stretched at a temperature above the glass transition temperature and below the melting point, or uniaxially stretched in an appropriately swelling solvent. It is generally made by stretching. Uniaxially stretched films produced by these stretching methods are susceptible to pinholes and principal strain due to the manufacturing process. Heat treatment is sometimes performed to reduce distorted sound, but the reduction may not be sufficient, or flatness may be completely lost, optical C2 non-uniformity may occur, or clouding may occur due to crystallization. be.

On the other hand, as a method for creating an alignment film different from the above method, The monomer is sandwiched between rubbed Nesa glass.

A method for creating a polarizing film by applying high voltage, aligning and polymerizing is described in JP-A-102-20J. However, in this method, expensive Nesa glass must be used, high voltage must be fully applied, 2. The temperature at which the liquid crystalline region of the liquid crystalline monomer appears is high, and unevenness occurs due to C polymerization shrinkage after polymerization. There are many problems in the film production process.

(Objective of the Invention) The object of the present invention is to produce a highly uniaxially oriented film that is free from pinholes, distortion, or unevenness due to shrinkage C2 during polymerization and has excellent optical C2 transparency.

(Structure of the Invention) According to the present invention, a composition containing at least two or more types of liquid crystalline polymers exhibiting a nemastic or smectic phase and having polymerizable functional groups in the molecule and a photopolymerization initiator is fully oriented. By sandwiching the composition between treated supports and polymerizing it by irradiating it with ultraviolet rays or visible light while maintaining the entire liquid crystal state, it is possible to form a composition with excellent optical transparency without pinholes, distortion, or unevenness. . It was found that highly uniaxially oriented films could be obtained.

Among the liquid crystal monomers, those having a structure such as acrylate represented by the general formula (CI) or methacrylate (methacrylate) as a polymerizable functional group are particularly desirable.

■ General formula [I] In general formula CI), R is H or CH3,
n is l, ko, 3, da 5, ot, 7,! , // can take an integer value.

X is a para-substituted aromatic ring or heterocycle as shown below, and of course, C2 is limited to the above C2. Note that 2 in formula X is -CN, -F, -C/! , B
r, OCH3, -〇C2H5, -oc3n7,
-□C4H9, -0C5H1□.

-QC6H13, -QC7H15, -NH2, -NO2
, -NHQ, -NO2 (Q means a lower alkyl group having 7 or less carbon atoms such as a methyl group or an ethyl group), but of course the above are not limited to C2 h0 In the case of this type of combination of different liquid crystalline seven monomers, the general formula of each monomer is CI]
Letting J and n2 respectively, it is desirable that the value of Δn=1nl-n2/ is l, 2.3.9, and the evening range l2.

For the 193 combinations, Δn 1-/n
1-n2/+Δn2:”/112 n3/, Δn3=
Each △n value of /111 n3/ is /, ko, 3,
It is desirable that the evening range is within the range. Similarly, it is desirable that the Δn value has the above-mentioned value for combinations of more than one type.

Furthermore, a combination containing at least one acrylate monomer is more desirable than a combination of methacrylate monomers, especially a combination containing at least two acrylate monomers. If methacrylate monomer is included in the combination, it may become difficult to obtain a stable orientation for the same reason as mentioned above.

Examples of photopolymerization initiators used in the present invention include the following.

(1) Acetophenones (2) Benzophenones, etc. j lever (CH3)2NCH2CH2
Used in combination with 0H etc.

(3) Benzoins H (4) Benzyls (5) Michler ketones (61) Benzoin alkyl ethers (7) Benzyl dimethyl ketals -♂- (8) Thioxanthones (9) Polyhalogens Of course, it is limited to the above. However, they may be used in combination as required.

As the support, it is also possible to use glass, plastic sheets, or belts or drums plated or vapor-deposited with metals such as stainless steel, chrome, and aluminum.

The amount added is usually 0°2~j to 2 liquid crystalline monomers.
wt% seems to be accumulating.

Examples of plastic sheets include cellulose, cellulose derivatives such as cellulose triacetate, cellulose diacetate, and cellulose acetate butyrate, polyesters such as polyethylene terephthalate and polyethylene naphthalate, polyolefins such as polycarbonate, polypropylene, and polyethylene, polyvinyl alcohol, polyvinyl chloride, Polyvinylidene chloride, nylon, polystyrene, etc. can be used.

The orientation treatment may be performed by rubbing the support surface with metal, natural fibers such as cotton, wool, or synthetic fibers such as nylon, polyester, acrylonitrile, etc., or by coating the surface with polyimide, boria ξ-d, polyvinyl alcohol, etc. It may be subjected to a rubbing treatment with the above-mentioned fibers or the like, or it may be entirely coated with a suitable surfactant.

In order to maintain the monomer in an all-liquid crystal state, the temperature of the atmosphere may be controlled to be above the crystal e-liquid crystal transition temperature (Tc) and below the liquid crystal e isotropic liquid transition temperature (Ti) of the liquid crystal monomer.

Examples of radiation that can be used as a polymerization C compound include ultraviolet rays.

This liquid crystalline monomer composition includes materials that do not destroy the liquid crystallinity of the composition, and materials that do not destroy the composition (in particular, dichroic dyes, ultraviolet absorbers, low-molecular liquid crystals, or gap agents such as glass beads). may be added.

As the dichroic dye, it is possible to use, for example, anthraquinone and azo dyes that are used as guests in normal guest-host liquid crystals.

The film obtained by the method of the present invention may be used while being sandwiched between supports, or may be used after being peeled from the support after polymerization.

Examples will be described below, in which birefringence was measured by measuring retardation using a polarizing microscope with a compensator using white light, and dividing this value by the thickness of the film.

1. Synthesis of liquid crystal monomers 1. Two explanations will be given.

(1) Synthesis of liquid crystalline 7-mer 6H) J''00ml methanol fFil2,derhydroxyg'-cyanobiphenyl 100f(o,s/comole) in which KUHs 4tfl-(0-unit/Vmol) was dissolved. ) and t-bromo-l-hexanolta 3f (0.1 l comol) were added, heated under reflux for 73 hours, and extracted with ice water (dry cold water).The extract was concentrated under reduced pressure using a total evaporator. Column treatment (carrier: Wako gel C
-200, developing solvent hexane/THF) k, g-(
, <-hydroxyhexyloxy) t, tT -cyanobipheni/I/ t j S' (yield go%) 1-
Obtained.

This g-(+-hydroxyhexyloxy)-da'-cyanobiphenyl ≦ ψ (00,22 mol) and triethylamine 31f (0,31 mol) total 600 ml of THE'
This solution was cooled to 1 pm, and the acrylic/Lz acid chloride 2 (1"1 l (0,
2 mol)' (Dropped over zJO minutes, and then 1 nit~
After reacting at 10°C for 1 hour, the mixture was poured with ice water and extracted with ethyl acetate. The yellow solid obtained by concentrating the extract to dryness was recrystallized once from a mixed solvent of hexane-THF to obtain goo [ω (pro-neuroxy)hexyloxy] a'
-cyanobiphenyl t,t9f/(yield: 9%) was obtained.

Synthesis of [abbreviated as YuH] (Synthesized in a circular manner with 6H described in 11).

(3) Liquid crystalline monomer.

Synthesis of It was synthesized in the same manner as +H described in (1).

(4) liquid crystal monomer, Synthesis of (1) and synthesized in the same manner as 7:6H.

Example/ PIX-/Koo-o-da (manufactured by Hitachi Chemical) was applied as an alignment agent using a Cobin coater, heat treated, and then coated in a fixed direction with a nylon cloth. - As a photopolymerization initiator between rubbed glass plates.

Added liquid crystal monomer H/liquid crystal monomer O H//
/ (weight ratio) was loaded on the glass cell to a thickness of 0 μm, and the glass cell was heated to 7°C for 7 days and then cooled. z
ooc, using a jKW ultra-high pressure mercury lamp! Polymerization was carried out by light irradiation for seconds. When the glass was removed after polymerization, a uniform, transparent and flexible alignment film was obtained, and the birefringence value of this film was Q,/9.

Comparative Example/Example/Liquid crystalline monomer composition f tcH3/
/ i CH3///C weight ratio), and in the same manner as in Example 1, an attempt was made to create a C2/C1 alignment film.

However, once the glass cellke is heated to 7℃,
Upon cooling, a structure peculiar to the smectic phase is formed,
No uniform orientation occurred.

Comparative Example The following compound was used alone as a liquid crystal monomer and alignment and polymerization were carried out in the same manner as in the example, but only a non-uniform alignment film with different birefringence was obtained for each part C2. (It was heated to 1.00C and then cooled.)

Patent Applicant: Fuji Photo Film Co., Ltd. Procedural Amendment Document Showa to Year 1/Monday Rakuten Office 6 Kawa I],
Display of case: Showa tO year patent application No. 2//Jilt No. 2, Title of invention: Alignment film preparation method 3, Person making the amendment Relationship with the case: Patent applicant Location: 210-4 Nakanuma, Minamiashigara City, Kanagawa Prefecture, Amendment: Subject Column 5 of the "Detailed Description of the Invention" of the specification, contents of amendment (1) The following sentence is inserted between the first line and the seventh line of the specification.

"The amount of photopolymerization initiator added is usually O, Co~jwt4 relative to the liquid crystal monomer." (2) "The amount of photopolymerization added is... ...
...is desirable. ” to be deleted.

Claims (1)

[Claims] A composition that exhibits a nematic phase or a smectic phase and contains at least two types of liquid crystal monomers having a polymerizable functional group in the molecule and a photopolymerization initiator is supported on or between supports that have been subjected to an alignment treatment. . A method for producing an alignment film, which comprises polymerizing the composition by irradiating it with ultraviolet rays or visible light while maintaining the composition in a liquid crystal state.