JPH02176709A - Polarizing film and its manufacture - Google Patents

Abstract

PURPOSE:To improve moisture resistance and optical characteristics by forming the polarizing film of a conjugate high polymer layer and a nonpolarizing plastic layer. CONSTITUTION:The conjugate high polymer part of a polarizing filter consisting of the nonpolarizing plastic film layer and nonpolarizing plastic layer is a change migration complex, so it has conductivity. Therefore, when the conjugate high polymer layer is present on at least one surface of the nonpolarizing plastic, the surface of an obtained polarizing filter is conductive. Further, the film is superior in thermal, chemical, and mechanical stability because of conjugate structure. Consequently, the optical characteristics and moisture resistance are improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a novel polarizing film with excellent moisture resistance and weather resistance for use in liquid crystal display devices, etc., and a method for producing the same.

Conventional technology Liquid crystal display elements have suppressed the market for competing electronic display elements and have dominated the fields of watches and calculators, and have recently been used in various measuring instruments, Baum electronics equipment, and office automation equipment such as personal computers and word processors. It is even used in motorcycles and cars. Along with this, the demand for polarizing films has increased dramatically.

Conventional polarizing films are roughly divided into three types manufactured by the following methods.

(1) After adsorbing iodine to a polyvinyl alcohol film, the film is l-axis stretched, or after the polyvinyl alcohol film is uniaxially stretched,
A polarizing film (H film) that has a polarizing function by adsorbing iodine.

(2) The polarizing function can be achieved by adsorbing a dichroic dye on a transparent plastic film and then stretching the film along the l-axis, or by stretching the transparent plastic film uniaxially and then adsorbing the dichroic dye. Applied polarizing film (L film).

(3) A polarizing film (K film) in which a polarizing function is imparted to a transparent plastic film by creating directional double bonds within the film before or after uniaxially stretching the film.

Of the three types of polarizing films mentioned above, the I (film) has excellent optical properties but is inferior in moisture resistance, the L film allows a wide range of color tones to be freely selected but is inferior in optical properties and moisture resistance. Although it has excellent moisture resistance, no one with satisfactory optical properties has been developed.

On the other hand, ever since it was discovered that doped polyacetylene exhibits metallic conductivity, research on conductivity using polyacetylene has been actively conducted, as well as the development of new conjugated polymers.

Attempts to apply this conjugated polymer to polarizing films were made in JP-A-61-239107 and JP-A-62-239.
No. 108. These technologies focus on the conductivity of conjugated polymers, and provide a conjugated polymer layer on a polarizing film to integrate the polarizing film and electrode of a liquid crystal display element. It is not a polarizing film that utilizes the polarizing ability of In addition, since the polarizing film produced by this method has a polymer layer of a five-membered heterocyclic compound on at least one surface of the polarizing film, although it has electrical conductivity, the single transmittance is poor. Among its optical properties, it has the disadvantage of poor display visibility (brightness, ease of viewing).

Due to the material that constitutes it, there are problems such as poor moisture resistance and poor optical properties.

The present invention has been made to solve these problems.

Means for Solving the Problems The present inventors conducted intensive studies to solve the above problems, and found that conjugated polymers have excellent polarizing ability, and developed a non-polarizing plastic layer. After stretching a composite film consisting of a conjugated polymer layer or a non-polarizing plastic film containing an oxidizing agent along the l-axis, the film is brought into contact with a conjugated polymer monomer to polymerize the conjugated polymer. They discovered that a polarizing film could be produced by doing this, and completed the present invention.

The conjugated polymer portion of the polarizing film comprising the conjugated polymer layer and the non-polarizing plastic layer of the present invention is a charge transfer complex and therefore has electrical conductivity. Therefore, when the conjugated polymer layer is present on at least one surface of the non-polarizing plastic, the surface of the resulting polarizing film becomes conductive. Additionally, due to its conjugated structure, the film has excellent thermal, chemical, and mechanical stability.

The conjugated polymer, which is one of the constituent elements of the polarizing film of the present invention, includes all general conjugated polymers having a molecular structure in which the main chain is conjugated.

Examples of such are polypyrrole, polythiophene, polyfuran, polyselenophene, polyaniline,
Polypyridazine, polyazophenylene, polyparaphenylene, polynaphthalene, polyanthracene, polyacetylene, polyacene, polyparaphenylene vinylene, and their substituted products poly(3,4-alkylpyrrole), poly(34-arylpyrrole), Examples include poly(N-alkylpyrrole) and poly(3-alkylthiophene). Among them, conjugated polymers having a substituent at the 3-position or 3.4-position of a 5-membered heterocyclic compound polymer such as polypyrrole, polythiophene, polyfuran, polyselenophene, etc., such as poly(3゜4-alkylpyrrole) , poly(34-arylpyrrole), poly(3-alkylthiophene), and the like are preferred.

In addition, the non-polarizing plastic which is another component of the present invention includes polyester-based, polycarbonate-based, polyethersulfone-based, polyimide-based, polyamide-based, halogenated vinyl polymer system, halogenated vinylidene polymer system, Examples include those based on ethylene-vinyl acetate copolymer, cellulose, polyvinyl butyral, and liquid crystal polymer, and those with high transparency when stretched are particularly preferred. Furthermore, if moisture resistance or weather resistance is not particularly required, polyvinyl alcohol-based materials are preferred.

The polarizing film of the present invention can be manufactured by the following method. (1) After a non-polarizing plastic film containing an oxidizing agent is stretched along the l-axis, the film is brought into contact with a conjugated polymer monomer to polymerize the conjugated polymer. (2) A non-polarizing plastic film containing an oxidizing agent is brought into contact with a conjugated polymer monomer to polymerize the conjugated polymer, and then the film is stretched along the l-axis. (3) If the conjugated polymer is soluble in a solvent, dissolve the conjugated polymer obtained by electrolytic oxidative polymerization or chemical oxidative polymerization in an appropriate solvent, and cast the solution on a non-polarizing plastic film. , the film is oriented in the l-axis. (4) When the conjugated polymer is soluble in a solvent, the conjugated polymer is dissolved in an adhesive for non-polarizing plastic films, and the adhesive is used to adhere two non-polarizing plastic films; The film is uniaxially stretched. Of the above manufacturing methods, the polarizing films manufactured by methods (1), (2), and (3) have a conjugated polymer layer on the surface layer, so they are conductive polarizing films. Another transparent film may be superposed thereon for the purpose of protecting the conjugated polymer layer. Examples of oxidizing agents that can be used in the production methods (1) and (2) include ferric chloride, potassium dichromate, potassium permanganate, potassium persulfate, ferric chloride, ruthenium chloride, and platinum chloride. Can be mentioned. Methods of incorporating oxidizing agents into non-polarizing plastics are known. The amount of the oxidizing agent blended is preferably about 0.1 to 10% by weight. Examples of solvents that can dissolve conjugated polymers include toluene and the like.

In addition, as adhesives for glass films that can be used in polarizing film manufacturing method (4), phenol-based, epoxy-based, vinyl-based, acrylic acid-based, isocyanate-based adhesives or hot-melt adhesives are used. However, if thermal stability or impact resistance is required, it is preferable to use a thermosetting adhesive such as a phenolic or epoxy adhesive. Additionally, depending on the non-polarizing plastic used, solvent cement, dope cement, and monomer cement can also be used.

As mentioned above, the conjugated polymer can be obtained by electrolytic oxidation polymerization method or chemical oxidation polymerization method. In the electrolytic oxidation polymerization method, a conjugated polymer monomer and a supporting electrolyte are dissolved or dispersed in a suitable polar solvent to form an electrolytic solution, and a voltage is applied between two electrode plates immersed in the electrolytic solution. Create a polymer. The material and shape of the electrode used at this time are not particularly limited, and ordinary conductive substances such as metals and semiconductors can be used. Applied voltage is usually 0.230v1
Preferably it is 0.2-10V. As the supporting electrolyte for the electrolytic reaction, conventionally known electrolytes used for normal electrolytic reactions can be used.

On the other hand, in the chemical oxidative polymerization method, a conjugated polymer monomer and an oxidizing agent are dissolved or dispersed in a suitable polar solvent, and the complex
Oxidative polymerization of membered cyclic compounds. The oxidizing agent used in this case is an oxygen-containing oxidizing agent or a transition metal compound known as a Lewis acid, such as potassium dichromate, potassium permanganate, potassium persulfate, ferric chloride, Examples include ruthenium chloride and chloroplatinic acid.

Effects of the Invention The polarizing film of the present invention is significantly different from conventional films in that it utilizes the polarizing properties of a conjugated polymer layer.

In addition, due to the presence of the conjugated polymer layer, it has excellent thermal, chemical, and mechanical stability. In addition, when the conjugated polymer layer is exposed on the surface, the surface of the polarizing film becomes conductive,
Expands the range of uses.

[Examples] The present invention will be specifically described below with reference to Examples, but the present invention is not limited only to these Examples.

Example 1 0.19 g of poly-3-hexylthiophene prepared by a chemical oxidative polymerization method was dissolved in 100 d of toluene.

This toluene solution was applied to a polyvinyl chloride film.
3-hexylthiophene was cast to a thickness of about 0.5 μl, and the film was dried.

The obtained film was immersed in a 10% ferric chloride acetonitrile solution for 10 minutes, and the film was washed with ion-exchanged water.
It was dried and doped with poly-3-hexylthiophene.

This film was stretched 4 times in one direction at 90°C to obtain a film colored with black edges. The absorption spectrum of this film is shown in FIG. Curve 1 in Figure 1 is the absorption spectrum of the single film obtained in this example.Curve 2 is the absorption spectrum when two films are stacked so that the stretching directions of the films are parallel to each other.Curve 3 is the absorption spectrum of the film obtained in this example. This is an absorption spectrum obtained when two films are stacked so that the directions are perpendicular to each other. As is clear from the figure, the film obtained in this example exhibits high polarization ability in the visible light and near-infrared regions of 40 (1 to 1000 nm).

Also, when the conductive dust on this film was measured using a four-probe method, it was found to be 0. ]S/am.

The optical characteristics are MCPD110A manufactured by Otsuka Electronics Co., Ltd.
Measurements were made using a type instantaneous multi-photometering system.

Comparative Example Polarizing film containing iodine and using polyvinyl alcohol as a base material (NPFF1225DU manufactured by Nitto Electric Industry Co., Ltd.)
) The toluene solution of poly-3-hexylthiophene used in Example 1 was cast on the surface of the film, and the film was dried. At this time, the thickness of the poly-3-hexylthiophene was adjusted to be approximately Olμ. The obtained film was immersed in a 10% ferric chloride acetonitrile solution for 10 minutes, and the film was washed with ion-exchanged water and dried to bring poly-3-hexylthiophene into a taupe state. The conductive dust on the surface of this polarizing film was 2 S/cm.

The absorption spectrum of this film is shown in FIG.

Curve 1 in FIG. 2 is the absorption spectrum of the film obtained in this comparative example, curve 2 is the absorption spectrum of the film obtained in Example 1, and curve 3 is the absorption spectrum of the NPF-F'1225DU film.

As is clear from the figure, the film obtained in this comparative example had poor single transmittance and poor display visibility (brightness, ease of viewing).
It is inferior to

Example 2 0.1 g of poly-3-hexylthiophene produced by electrolytic oxidation polymerization method was dissolved in 100 ml of toluene.

This toluene solution was cast onto a polyvinyl alcohol film containing 1% ferric chloride so that the thickness of poly-3-hexylthiophene was approximately 0.5 μm, and ethanol and
It was washed with ion-exchanged water to remove excess ferric chloride.

After drying the film, heat the film at 70°C in one direction for 5
A film with a black edge color was obtained by stretching the film twice. The optical properties of this film were almost the same as those shown in FIG.

Example 3 10% polyvinyl chloride film containing 1% ferric chloride
3-hexylthiophene acetonitrile solution to obtain a polyvinyl chloride film containing poly-3-hexylthiophene. At this time, the dipping time was adjusted so that the thickness of the poly-3-hexylthiophene was approximately 0.5 μm.

Further, excess ferric chloride was removed by washing with acetonitrile and ion-exchanged water.

This film was stretched 4 times in one direction at 90°C to obtain a film colored with black edges. The optical properties of this film were the same as in FIG.

Example 4 A polyvinyl chloride film containing 1% ferric chloride was heated to 90°C.
The poly-3-
A film colored with a black edge color containing hexylthiophene was obtained. At this time, the immersion time was adjusted so that the thickness of the poly-3-hekylene thiophene was approximately 0.5 μm. Further, excess ferric chloride was removed by washing with acetonitrile and ion-exchanged water.

The optical properties of this film were almost the same as those shown in FIG.

Example 5 0.1 g of poly-3-hexylthiophene produced by a chemical oxidative polymerization method was dissolved in 100× toluene (!).

This toluene solution was applied onto a polyethylene terephthalate film so that the thickness of poly-3-hexylthiophene was approximately 0.5 mm.
The film was cast to a thickness of μm and dried. The obtained film was dissolved in 10% ferric chloride acetonitrile solution for 1 hour.
After immersion for 0 minutes, the film was washed with ion-exchanged water, dried, and doped with poly-3-hexene-ruthiophene.

This film was stretched 3 times in one direction at 180°C to obtain a film colored with black edges.

The optical properties of the film were the same as in FIG.

This polarizing film was left in a thermostat at 150° C. for 12 hours, and then the optical properties of the film were examined, and the same properties as shown in FIG. 1 were obtained. Furthermore, when this polarizing film was left in water for 12 hours and the optical properties of the film were examined, the same properties as shown in FIG. 1 were also obtained. Therefore, the polarizing film according to the present invention has excellent moisture resistance and has heat resistance below the heat distortion temperature of non-polarizing plastic.

Example 6 0.1 g of poly-3-hexylthiophene produced by electrolytic oxidation polymerization method was dissolved in toluene at 100×C.

This toluene solution was added to the 10% polyvinyl chloride film tetrahydrofuran solution and mixed.

This mixed solution was cast onto a polyvinyl chloride film so that the thickness of poly-3-hexylthiophene was approximately 0.5μ, and another polyvinyl chloride film was placed on top of it to form two films. Glue and dry.

This film was stretched 3 times in one direction at 90°C to obtain a dark brown film. The absorption spectrum of this film is shown in FIG. Curve 1 in Figure 3 is the absorption spectrum of the single film obtained in this example, Curve 2 is the absorption spectrum of two films stacked so that the stretching directions of the films are parallel, and Curve 3 is the absorption spectrum of the film obtained by stretching the film. This is an absorption spectrum obtained when two films are stacked with the directions perpendicular to each other. As is clear from the figure, the film obtained in this example exhibits high polarization ability in the visible light range of 400 to 11,000 nm and in the near-infrared region.

Example 7 10% polyvinyl chloride film containing 1% ferric chloride
A polyvinyl chloride film containing polypyrrole was obtained. At this time, the dipping time was adjusted so that the thickness of the polypyrrole was approximately 0.5 μm.

Further, excess ferric chloride was removed by washing with acetonitrile and ion-exchanged water.

This film was stretched 4 times in one direction at 90°C to obtain a film colored with black edges. The optical properties of this film were almost the same as those shown in FIG.

Example 8 A polyvinyl chloride film containing 1% ferric chloride was heated to 90°C.
The film was stretched 4 times in one direction, and then immersed in a 10% pyrolacetonitrile solution to obtain a film containing polypyrrole and colored with a black edge color.

At this time, the dipping time was adjusted so that the thickness of the polypyrrole was about 0.5 μm. Further, excess ferric chloride was removed by washing with acetonitrile and ion-exchanged water.

The optical properties of this film were almost the same as those shown in FIG.

[Brief explanation of the drawing]

Figure 3 is a diagram showing the optical properties of an example of a polarizing film made of a conjugated polymer and a non-polarizing plastic according to the present invention. However, the conjugated polymer is in an oxidized state. Note that the measurement wavelength range is 300 nm, and the wavelength range is 400 nm to 700 nm.
nm and 700 nm to 11000 nm were measured separately, and the two were later glued together. Figure 2 is Nitto Electric Industry Co., Ltd.'s frame side optical film NPF-F.
'l 225DU, an example of a polarizing film having a conjugated polymer layer on the surface of the film, and an example of a polarizing film made of a conjugated polymer and a non-polarizing plastic of the present invention
This is an example absorption spectrum of a simple substance. FIG. 3 is a diagram showing the optical properties of an example of a polarizing film made of a conjugated polymer and a non-polarizing plastic according to the present invention. However, the conjugated polymer is in a neutral state. In addition, the measurement wavelength range is 300 nm, and the wavelength range is 400 nm to 700 nm.
and 700 nm to IO00 nm were measured separately, and both were later bonded together.

Claims (1)

[Claims] 1. A polarizing film comprising a conjugated polymer layer and a non-polarizing plastic layer. 2. The polarizing film according to claim 1, wherein the conjugated polymer layer is a 5-membered heterocyclic compound polymer having substituents at the 3-position or at the 3- and 4-positions. 3. A method for producing a polarizing film, which comprises uniaxially stretching a composite film comprising a conjugated polymer layer and a non-polarizing plastic layer. 4. After uniaxially stretching a non-polarizing plastic film containing an oxidizing agent, the film is brought into contact with a conjugated polymer monomer to polymerize the conjugated polymer, or
A method for producing a polarizing film, which comprises bringing a conjugated polymer monomer into contact with a non-polarizing plastic film containing an oxidizing agent to polymerize the conjugated polymer, and then uniaxially stretching the film. 5. Polarized light characterized by dissolving a conjugated polymer in a non-polarizing plastic film adhesive, bonding two non-polarizing plastic films using the adhesive, and uniaxially stretching the film. Film manufacturing method.