JPS6270406A - 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 (meth)acrylate on or between supports subjected to orientation treatment and polymerizing the monomer in a state of a liquid crystal by irradiation with a radiation. CONSTITUTION:A support (A) subjected to orientation treatment is obtained by rubbing a support made of glass, plastic (e.g., PP) or the like, if desired, coated with a polyimide, a polyamide or the like with a natural fiber, synthetic fiber or the like or is coated with a surfactant. A liquid crystal (meth)acrylate of formula I (wherein X is H, Cl, Br, CN or formula II, p is 1-6, n is 2-6, 8 or 11, and R is H or CH3), e.g., formula III, is supported on or between components A. This monomer, if desired after the addition of a polymerization initiator, an ultraviolet absorber, low-MW liquid crystal glass beads, etc., is polymerized by irrdiation with a radiation while the monomer is kept in a state of a liquid crystal.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention This invention relates to a method for making highly uniaxially oriented films. Highly uniaxially oriented films have strong mechanical strength in the direction of orientation, and are not only used for packaging films that take advantage of this strength and films that are laminated at right angles to each other, but also in the direction of orientation and the direction perpendicular to it. Utilizing its optical anisotropy, it can be used in retardation films, dyed with dichroic dyes and used in polarizing films, and also used as optical filter recording materials and display materials.

(Prior Art) Highly uniaxially oriented films have conventionally been produced by uniaxially stretching a melt-extruded or solution-cast film at a temperature above the glass transition temperature and below the melting point, or by stretching the film in an appropriate swelling solvent. It is generally made by stretching in the direction. Uniaxial films made by these stretching methods are easily strained due to the manufacturing process. Heat treatment is sometimes performed to alleviate the strain, but the relaxation may not always be sufficient, or the flatness may be impaired, or the material may become optically non-uniform or crystallized and become cloudy.

JP-A-10-10-203 describes a method of making a polarizing film by sandwiching a mer between rubbed Nesa glass and applying a voltage to cause alignment polymerization, but the method requires that all Nesa glass be used, and a high voltage electric field is applied. This is a very troublesome method in terms of the film production process.

Another drawback is that unevenness occurs after polymerization on a uniform film surface before polymerization.

(Objective of the Invention) The object of the present invention is to create a strain-free, optically transparent, and excellent uniaxial alignment by a new means completely different from these methods.

(Structure of the Invention) According to the present invention, liquid crystal acrylate or methacrylate represented by the following general formula (I) is sandwiched between supports subjected to gold orientation treatment, and is irradiated with radiation in a liquid crystal state. It has been found that a uniaxially oriented film can be obtained.

General formula (I) R:H or CH3 n:, 2.3, Hiroshi,! , 1.1 X:H, α, Br, CN, 0CpHp-4-t (
p is an integer from / to 2→ The liquid crystal acrylate or methacrylate used in the present invention may be used alone, or two or more types may be used in combination. Among these, acrylate monomers are particularly preferred, and cyan group-substituted monomers are most preferred.

As the support, it is also possible to use glass, a plastic sheet, or a belt or drum metal plated or vapor-deposited with metal such as stainless steel, chrome, or aluminum on one of the supports.

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

Orientation treatment may be carried out by rubbing the surface of the support with metal, natural fibers such as cotton, wool, or synthetic fibers such as nylon, polyester, acrylonitrile, etc., or by applying polyimide, polyamide, polyvinyl alcohol, etc., and applying the above-mentioned fibers to the support surface. A rubbing treatment may be performed, or a suitable surfactant may be applied.

In order to maintain the monomer in a liquid crystal state, the temperature of the atmosphere must be higher than the crystal zero liquid crystal transition temperature (Tc) of the liquid crystal monomer.
It is sufficient to control the temperature to be below the isotropic liquid transition temperature (Ti).

As the radiation used for polymerization, ultraviolet rays, electron beams, etc. can be used.

Into this liquid crystalline monomer, materials such as polymerization initiators, dichroic dyes, ultraviolet absorbers, and gap agents such as low-molecular liquid crystal glass beads are added to the extent that they do not destroy the liquid crystallinity of the monomer. There is no problem.

Examples of polymerization initiators include etc. can be used.

As dichroic dyes, 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 is sandwiched between supports. It may be used directly, or it may be used after being peeled off from the support after polymerization.

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

Synthesis example The following liquid crystalline acrylate was synthesized by the following method.

100m of KOH 3 hirot (o,ri hmol) dissolved
1 methanol solution, ≠-hydroxy≠'-cyanobiphenyl 1ooy (o, 72 mol) and 2-bromo-l
-Hexanolta 3r (o, t12 mol)'f: addition,
The mixture was heated under reflux for 13 hours, poured into ice water, and extracted using ethyl acetate. After concentrating the extract under reduced pressure using an evaporator, column treatment (carrier: Wakogel C-CO 00, developing solvent: Keene/THF), μ-(7-hydroxyhexyloxy)-≠'-cyanobiphenyl + tr(
Yield: 3%)? :Obtained.

This g-(+-hydroxyhexyloxy)-Hiro'-cyanobiphenyl 6! (O, 22 mol) and triethylamine 31y (0,31 mol) were dissolved in t00 ml of gold THF, this solution was cooled to 2 s 0C, and while stirring with a Starsea, acrylic acid chloride 2≠9 (o, 2A mol) was dissolved in THF. ) over 30 minutes, and more! After reacting at ~100C for 1 hour, the mixture was poured into ice water and extracted with ethyl acetate. The yellow solid obtained by concentrating the extract to dryness was mixed with hexane, T
Recrystallized twice from a mixed solvent of HF to obtain ≠-[w(propenoyloxy)hexyloxy) <tl-cyanobiphenyl μF? (Yield: 2%) was obtained.

It was synthesized in exactly the same manner as compound (5).

Na3 It was synthesized in exactly the same manner as compound (5).

Example 1 PIX-/<Aoo-o≠ (manufactured by Hitachi Chemical) as an alignment agent
After applying it with a spin coater and heat treating it, do you rub it in a certain direction with a nylon cloth? The liquid crystal monomer (6) was added with k/wt% of the compound (4) as a photopolymerization initiator between the glass plates. The glass cell was heated to 7j0C and then cooled. ! Polymerization was carried out by irradiating light for 5 seconds at θ0C using a 2kWlfi high-pressure mercury lamp. After polymerization, when the glass was removed, a uniform and flexible film was obtained, and the birefringence value of this film was 0.7t.

Example λ The liquid crystal monomer (6) in Example 1 was changed to a mixture of liquid crystal monomer (5) and (force t to A film was obtained.The birefringence value of this film was 0./7.

Comparative Example: Polymerization was carried out in the same manner as in Example using liquid crystal of compound (8), but only a non-uniform film with different birefringence could be obtained in each part.

I O- Compound (8) CI (3 7-/MA Patent Applicant Fuji Photo Film Co., Ltd.-/l- Procedural Amendment 1989 to February 72-1, Case Description 1985 Patent Application No. 210t! No. 2, Title of the invention: Method for producing an oriented film 3, Relationship with the person making the amendment Case: Patent applicant Address: 210-4 Nakanuma, Minamiashigara City, Kanagawa Prefecture, Subject of amendment: “Detailed description of the invention” in the specification Column 5, page 7 of the statement of contents of the amendment, first line from the bottom.

February 22, 1970 - [21 Patent 1 Commissioner U71
, Incident Display Showa 6Q Patent Application No.-210411
No. 2, Title of the invention Method for producing an oriented film 3, Contact information for the person making the amendment 21-26-30-4, Nishi-Azabu, Minato-ku, Tokyo 106 106 Subject of the amendment The "Claims" column of the specification and " Column 5 of "Detailed Description of the Invention", contents of amendment (1) Specification cylinder ≠ page jth line "0CpHp+IJ is corrected as rQCriH21)+IJ.

(2. Amend the claims in a separate sheet.

Attached Patent Claims A liquid crystalline acrylate or/and methacrylate represented by the general formula (I) is supported on or between supports subjected to alignment treatment, and irradiated with radiation while maintaining the monomer in a liquid crystal state. A method for producing an oriented film characterized by polymerization.

where X: H,, C1, Br, CN, 0CI) H2p+
1 (integer at p:/-Jt-) n: 2.3, ! ,t1♂,l/R:H,CH3

Claims (1)

[Claims] Liquid crystalline acrylate or/
and a method for producing an oriented film, which comprises supporting methacrylate on or between supports that have been subjected to an alignment treatment, and polymerizing the monomer by irradiating it with radiation while maintaining the monomer in a liquid crystal state. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ General formula (I) where X: H, Cl, Br, CN, OCpHp_+_1
(p: an integer from 1 to 6) n: 2, 3, 4, 5, 6, 8, 11 R: H, CH_3