KR20050029594A - Polarizing film containing syndiotactic polyvinylalcohol with dye and method of producing the same - Google Patents

Abstract

Provided are a method for preparing a syndiotactic poly(vinyl alcohol)-based polarizing film with a dye, its polarizing film which has a very excellent polarizing effect and is improved in the durability at a high temperature and a high humidity, and a liquid crystal display device containing the polarizing film. The method comprises the steps of firstly drawing a syndiotactic poly(vinyl alcohol) film; dyeing the drawn film in a dye solution containing 0.01-5.00 wt% of a dye at a temperature of 0-70 deg.C for 20 min or less; and secondly drawing the dyed film. Preferably the second drawing process is carried out in a boric acid aqueous solution, a formalin aqueous solution or their mixture of a concentration of 0.1-10.0 wt%. Preferably at least one of the first and second drawing processes is a band drawing or wet drawing performed with a constant drawing ratio at a temperature of 10-230 deg.C. Preferably the dye is a direct dye.

Description

Polarizing Film Containing Syndiotactic Polyvinylalcohol with Dye and Method of Producing the Same

Field of invention

The present invention relates to a polyvinyl alcohol polarizing film and a method of manufacturing the same. More specifically, the present invention relates to an alternating polyvinyl alcohol dye-based polarizing film having improved durability and polarization effect at high temperature and high humidity, and a manufacturing method thereof.

Background of the Invention

Polarizing film used in the field of display serves to change the vibration plane of the light to the plane polarization. Such polarizing films are used for vehicle mounting, aircraft, outdoor installation, and are used for watches, electronic calculators, liquid crystal TVs, laptops, mobile phones, large projectors, and the like. In particular, recently, with the development of the electronics industry, its use is greatly increased, and polarizing film is attracting attention as the core of the parts and materials field of the liquid crystal display (LCD), which is emerging as a next-generation flat panel display device to replace the CRT.

Polyvinyl alcohol (PVA: polyvinylalcohol) is uniquely used as a material of a polarizing film, and PVA has been continuously studied for 70 years since it was first disclosed in German Patent No. 685,048 by German Hermann in 1931. In particular, it is used not only as a film but also as a high functional material, such as an adhesive agent, a medical polymer, and a contact lens.

PVA used as a polarizing film is introduced with iodine, dyes, pigments or conjugated double bond (conjugated double bond) in order to impart dichroism, and is oriented in the stretching direction to produce a PVA polarizing film.

At this time, there are two kinds of PVA used, an hybrid PAT represented by the following Chemical Formula 1 and a syndiotactic PVA represented by the following Chemical Formula 2.

[Formula 1]

[Formula 2]

Many monomers are used for synthesizing precursors for producing hybrid or alternating PVA. Vinyl trifluoride has been widely used as a monomer for synthesizing precursors for alternating PVA. However, this monomer has a problem that the price is very expensive and does not express sufficient alternating arrangement. Vinyl pivalate is known to express the best alternating arrangement due to the steric hindrance effect of the tertiary butyl group. The saponification method was not easy, but the saponification method was recently established by Yamamoto et al. Or Ha and Lyoo.

However, all precursors for obtaining alternating PVA, including those disclosed in Korean Patent No. 179,940, are very expensive compared to polyvinyl acetate, which is a polymerization monomer of polyvinyl acetate used as a precursor of hybrid array PVA. It was made through a complicated route such as ultraviolet irradiation or gamma irradiation.

On the other hand, in order to give a dichroism in order to use a hybrid array or alternating array PVA as a polarizing film, iodine is used a lot. Furthermore, the polarizing effect is increased by uniaxially stretching such a PVA iodine type film and improving the orientation. The PVA iodine polarizing film may be prepared by drawing an unstretched PVA film in a uniaxial direction and then adsorbing iodine, or by first forming an iodine complex and then stretching the film.

PVA and iodine form a complex of PVA-oligoiodine in the crystal region and the amorphous region in the PVA film, wherein the oligoiodine ion oriented in the stretching direction exhibits a polarizing effect. Such a complex is known to be formed under the influence of 1,2-glycol content, stereoregularity, degree of saponification, formalin treatment, etc. in the main chain, and thus polarization effect is affected.

However, PVA iodine-based polarizing film has the advantage of excellent initial polarization characteristics, but the durability is weak due to the sublimation of iodine, especially in high temperature, high humidity conditions the problem is more serious.

In order to compensate for this disadvantage, there is a method of adsorbing iodine on PVA film and then rapidly treating in formalin aqueous solution or boric acid solution to introduce crosslinking between PVA chains. And a method of bonding a PVA film to a protective film which is not easy to transfer moisture, such as a film obtained by applying and polymerizing a polyfunctional acrylate.

In addition, dichroic organic pigments are used instead of iodine in Korean Patent Publication No. 1998-68290, Korean Patent Publication No. 2001-104259, Korean Patent Publication No. 2001-100955, Korean Patent Publication No. 2001-0100941, and the like. By producing a PVA dye-based polarizing film to improve the durability is disclosed.

There is also a method of introducing a double bond onto the PVA main chain by partially dehydrating PVA itself with an acid catalyst without using iodine or dyes.

However, these methods still do not solve the fundamental problems such as deformation of the film in a high temperature, high humidity environment and degradation of polarization.

On the other hand, the stretchability of the film is known to be affected by the molecular weight and molecular weight distribution of the polymer material used, the crystallinity of the unstretched film, and the concentration of the polymer solution used in the film production. In general, as the molecular weight increases, the draw ratio increases. When the molecular weight is large enough, the draw ratio mainly depends on the film forming concentration.

In particular, PVA has an extreme elastic modulus of 236 GPa, which is as large as polyethylene, and thus attracts attention as a high strength and high modulus polymer material, but due to the strong intermolecular and intramolecular hydrogen bonds between adjacent hydroxy groups, the polymer chain is used in general stretching methods. It is difficult to orientate sufficiently so that the drawability is not good, and due to these disadvantages, inherent ultimate physical properties are difficult to be expressed. In other words, it is difficult to completely unfold the polymer chain by the general stretching method. To overcome this problem, gel stretching method, single crystal mat stretching method and high temperature band stretching method have been studied. Among these methods, the high temperature strip stretching method is stretched by applying heat to a local region of a sample, and thus has a merit of less refolding of chains, less pyrolysis, and no need for chemicals, compared to general thermal stretching methods.

Korean Patent No. 179,940 discloses a production method of polymerizing vinyl pivalate at high temperature to produce polyvinyl alcohol and stretching the film once. However, this film still suffers from weak durability and polarization effect at high temperature and high humidity.

Therefore, the present inventors prepared a PVA dye-based polarizing film by using a new stretching technique for stretching the PVA film synthesized by the improved polymer synthesis technology before and after dyeing, in order to overcome the problems of the prior art, high temperature, high humidity It is to improve the durability in and to complete the alternating polyvinyl alcohol dye-based polarizing film with excellent polarization effect.

An object of the present invention is to provide an alternating polyvinyl alcohol dye-based polarizing film to which a novel stretching technique is applied to a PVA film.

Another object of the present invention is to provide an alternating polyvinyl alcohol dye-based polarizing film which is significantly improved durability at high temperature and high humidity.

Still another object of the present invention is to provide an alternating polyvinyl alcohol dye-based polarizing film having excellent polarization effect.

Another object of the present invention is to provide an alternating polyvinyl alcohol dye-based polarizing film having high stereoregularity.

Still another object of the present invention is to provide an alternating polyvinyl alcohol dye-based polarizing film having excellent durability even without bonding a protective film on both sides of the film.

Still another object of the present invention is to provide a method of manufacturing an alternating polyvinyl alcohol dye-based polarizing film.

The above and other objects of the present invention can be achieved by the present invention described in detail.

Summary of the Invention

The alternating polyvinyl alcohol dye-based polarizing film according to the present invention is the first stretching the alternating array PVA film, and the stretched film is dyed for 1 second to 20 minutes in a dye bath of 0 to 70 ℃ of 0.01 to 5% by weight dye And it is characterized in that it is prepared in the second stretching step of the dye film again. In this case, at least one of the first and second stretching may be a band stretching, a wet stretching, etc., at least one of which is performed at a constant stretching ratio at 10 to 230 ° C., and the second stretching may be an aqueous solution of boric acid having a concentration of 0.1 to 10 wt%, formalin. Aqueous solution, or a mixture thereof.

The alternating PVA film according to the present invention is polymerized with vinyl acetate and / or vinyl pivalate by adding an initiator used at low temperature, thereby obtaining a number average polymerization degree of 3,600 to 22,000, a saponification degree of 90.0 to 99.9%, and an alternating arrangement. It is preferable to prepare an alternating arrangement PVA having a diad group content of 53 to 68% and to dissolve the prepared PVA in a solvent such as water, dimethyl sulfoxide, or a mixture thereof.

Alternately arranged PVA dye-based polarizing film prepared by improved polymer synthesis technology and novel stretching technology according to the present invention can be used in a display device such as LCD, wherein the polarizing effect of the polarizing film is very excellent, at high temperature and high humidity Durability is also greatly improved.

Hereinafter, the content of the present invention will be described in detail.

Detailed Description of the Invention

According to the present invention, by applying an improved polymer synthesis technology to synthesize alternating PVA in a simple process at a low cost and low temperatures, and to dissolve the synthesized PVA in a solvent such as water or dimethyl sulfoxide to produce an alternating PVA film By applying a novel stretching technology that stretches before and after dyeing the film on the produced film, the alternating array PVA dye-based polarizing film is manufactured, so that the polarizing effect is not only excellent but also excellent durability at high temperature and high humidity. It is to prepare a polarizing film.

Synthesis of Alternating PVA

By adding an initiator used at a low temperature to polymerize vinyl acetate and / or vinyl pivalate, alternating PVA having a number average polymerization degree of 3,600 to 22,000, a saponification degree of 90.0 to 99.9%, and an alternating diad group content of 53 to 68% is obtained. Synthesize

When synthesizing the alternating arrangement PVA, it was generally performed at a high temperature of 100 ° C or higher. However, in Korean Patent Laid-Open Publication No. 2002-62175 invented by the present inventors, polyvinyl carbonate is prepared by suspending and polymerizing vinyl pivalate by adding azobisdimethylvaleronitrile, which is an initiator, at a low temperature of 20 to 70 ° C. Alternately arranged polypivalate was prepared by a simple chemical reaction without complex paths such as irradiation or gamma irradiation.

Therefore, the present invention synthesizes an alternating arrangement PVA having improved stereoregularity by not only adding azobisdimethylvaleronitrile or the like which can be used at low temperatures but also copolymerizing vinyl acetate with vinyl acetate, which is very inexpensive.

When copolymerizing vinyl acetate and vinyl pivalate, the method includes bulk copolymerization, solution copolymerization, emulsion copolymerization, suspension copolymerization, and the like. The vinyl pivalate may be polymerized alone. At this time, the number average polymerization degree of the alternating arrangement PVA produced is 3600-22,000, the saponification degree is 90.0-99.9%, and the alternating diad group content is 53-68%.

Preparation of Alternating PVA Films

The alternating PVA film prepared according to the present invention is dissolved in a solvent such as water, dimethyl sulfoxide, or a mixture thereof to prepare an alternating PVA film.

When the alternating arrangement PVA is dissolved in a solvent such as water or dimethyl sulfoxide, the concentration of PVA can be adjusted in various ways. In particular, in consideration of environmental problems and economic costs and considering the permeability of the produced PVA film, it is most effective to dissolve the PVA film in water. At this time, the alternating PVA film of various concentrations is prepared using 20 to 500 mol of water, which is a solvent, for 1 mol of the alternating PVA.

Preparation of Alternate Arrayed PVA Dye Polarizing Film

By applying a novel stretching technique to the alternating PVA film prepared according to the present invention to produce an alternating array PVA dye-based polarizing film, it is characterized in that the stretching before and after the PVA film is dyed. That is, first stretching the alternating PVA film, dyeing the stretched film for 1 second to 20 minutes in a dye bath at 0 to 70 ℃ of 0.01 to 5% by weight of the dye, and second stretched the film again will be.

In this case, at least one of the first and second stretching may be a band stretching, a wet stretching, etc., at least one of which is performed at a constant stretching ratio at 10 to 230 ° C., and the second stretching may be an aqueous solution of boric acid having a concentration of 0.1 to 10 wt%, formalin. Aqueous solution, or a mixture thereof. Further, the second stretching may be performed after washing, fixing, and drying the dyed film. Washing, fixing and drying methods can be easily carried out by those skilled in the art.

When dyeing the first stretched PVA film with a dye, various dyes may be used, and the type of dye is not limited. Preferably, a direct dye is used, and specifically, there are Direct Red, Direct Blue, Direct Yellow, and Direct Black.

Further, the first stretched film is dyed for 1 second to 20 minutes in a salt bath at 0 to 70 DEG C of 0.01 to 5% by weight of dye, and preferably 1 second to 20 minutes at 10 to 60 DEG C. Dye for 10 minutes.

Alternately arranged PVA dye-based polarizing film prepared according to the present invention, unlike the conventional PVA polarizing film is melted or deformed in water at 50 ℃, almost no deformation in water of 80 ℃ or more, the average transmittance of 40% It has an excellent polarization effect with an average polarization degree of 99.5% or more. In particular, since the alternating arrangement PVA dye-based polarizing film according to the present invention is very excellent in durability, it can be used even without a protective film such as TAC used on both sides of the conventional PVA polarizing film.

Alternately arranged PVA dye-based polarizing film according to the present invention is used in a variety of display devices exhibiting excellent polarization effect and durability. In particular, it can be used in a liquid crystal display (LCD), which can be easily carried out by those skilled in the art.

The invention can be better understood by the following examples, which are intended for the purpose of illustration of the invention and are not intended to limit the scope of protection defined by the appended claims.

Example

Example 1

80 mol of water was mixed with 1 mol of alternating PVA having a number average degree of polymerization of 10,000, saponification degree of 99.9%, and alternating diad group content of 56%. The solution was dissolved by stirring at 90 ° C. for 1 hour to prepare a solution. Poured into a stainless plate, vacuum dried for 40 hours at 40 ℃ to dry completely to prepare a film. The prepared film was stretched twice at 150 ° C. and dyed for 1 minute at a concentration of 1.0 wt.% Of 40 ° C. using a direct dye (C. I. Direct Red 81), and then stretched 2.5 times at 40 ° C. in an aqueous boric acid solution. The concentration of aqueous boric acid solution used was 3 wt.%.

Then, light is irradiated to the polarizing film manufactured using the ultraviolet-visible spectrophotometer, and the single transmittance, parallel transmittance (Y _∥ ) and orthogonal transmittance (Y _⊥ ) at each wavelength are measured, and the equation The degree of polarization (ρ) was calculated by.

The result showed a polarization of 99.6% and a transmittance of 40.5%. In addition, the durability test after 5 hours in a high temperature wet state (90 ℃, relative humidity: 85%) showed little change in polarization and transmittance, and the shape of the film did not change.

Example 2

80 mol of water was mixed with 1 mol of alternating PVA having a number average degree of polymerization of 6,000, 99.9% of saponification, and 57% of an alternating diad group, and then completely dissolved by stirring at 90 ° C. for 1 hour. Poured into a stainless steel plate, dried under vacuum at 40 ℃ for 40 hours to dry completely to prepare a film. The prepared film was stretched twice at 150 ° C., dyed for 2 minutes at a concentration of 0.5 wt.% Of 40 ° C. using a direct dye (C. I. Direct Red 81), and stretched 2.5 times at 40 ° C. in boric acid aqueous solution. The concentration of aqueous boric acid solution used was 3 wt.%. Measurements using an ultraviolet-visible spectrophotometer showed a polarization of 99.4% and a transmission of 40.3%. Durability test after 5 hours in high temperature wet condition (90 ℃, relative humidity: 85%) showed little change in polarization and transmittance and no change in film form.

Example 3

80 mol of water was mixed with 1 mol of alternating PVA having a number average degree of polymerization of 4,500, 99.9% of saponification, and 58% of an alternating diad group, and then completely dissolved by stirring at 90 ° C. for 1 hour. Poured into a stainless steel plate, dried under vacuum at 40 ℃ for 40 hours to dry completely to prepare a film. The prepared film was stretched twice at 150 ° C. and dyed for 1 minute at a concentration of 1.0 wt.% Of 40 ° C. using a direct dye (C. I. Direct Red 81), and then stretched 2.5 times at 40 ° C. in an aqueous boric acid solution. The concentration of aqueous boric acid solution used was 3 wt.%. Measurements using an ultraviolet-visible spectrophotometer showed a polarization of 99.7% and a transmission of 40.2%. Durability test after 5 hours in high temperature wet condition (90 ℃, relative humidity: 85%) showed little change in polarization and transmittance and no change in film form.

Example 4

80 mol of water was mixed with 1 mol of alternating PVA having a number average degree of polymerization of 4,000, a degree of saponification of 99.9%, and a content of alternating diad groups of 59%. Poured into a stainless steel plate, dried under vacuum at 40 ℃ for 40 hours to dry completely to prepare a film. The prepared film was stretched twice at 100 ° C., dyed for 1 minute at a concentration of 1.0 wt.% At 30 ° C. using a direct dye (C. I. Direct Red 79), and stretched 2.5 times at 40 ° C. in an aqueous boric acid solution. The concentration of aqueous boric acid solution used was 3 wt.%. Measurements using an ultraviolet-visible spectrophotometer showed a polarization of 99.2% and a transmission of 40.5%. Durability test after 5 hours in high temperature wet condition (90 ℃, relative humidity: 85%) showed little change in polarization and transmittance and no change in film form.

Example 5

80 mol of water was mixed with 1 mol of alternating PVA having a number average degree of polymerization of 3,700, saponification degree of 99.9%, and alternating diad group content of 60%. Poured into a stainless steel plate, dried under vacuum at 40 ℃ for 40 hours to dry completely to prepare a film. The prepared film was stretched twice at 150 ° C., dyed for 1 minute at a concentration of 1.0 wt.% Of 40 ° C. using a direct dye (C. I. Direct Red 79), and stretched 2.5 times at 40 ° C. in boric acid aqueous solution. The concentration of aqueous boric acid solution used was 3 wt.%. Measurements using an ultraviolet-visible spectrophotometer showed a polarization of 99.6% and a transmission of 40.3%. Durability test after 5 hours in high temperature wet condition (90 ℃, relative humidity: 85%) showed little change in polarization and transmittance and no change in film form.

Example 6

80 mol of water was mixed with 1 mol of alternating PVA having a number average degree of polymerization of 10,000, saponification degree of 99.9%, and alternating diad group content of 56%. The solution was dissolved by stirring at 90 ° C. for 1 hour to prepare a solution. Poured into a stainless steel plate, dried under vacuum at 40 ℃ for 40 hours to dry completely to prepare a film. The prepared film was stretched twice at 150 ° C., dyed for 2 minutes at a concentration of 0.5 wt.% Of 40 ° C. using a direct dye (C. I. Direct Blue 71), and stretched 2.5 times at 40 ° C. in boric acid aqueous solution. The concentration of aqueous boric acid solution used was 3 wt.%. Measurements using an ultraviolet-visible spectrophotometer showed a polarization of 99.6% and a transmission of 40.4%. Durability test after 5 hours in high temperature wet condition (90 ℃, relative humidity: 85%) showed little change in polarization and transmittance and no change in film form.

Example 7

80 mol of water was mixed with 1 mol of alternating PVA having a number average degree of polymerization of 6,000, 99.9% of saponification, and 57% of an alternating diad group, and then completely dissolved by stirring at 90 ° C. for 1 hour. Poured into a stainless steel plate, dried under vacuum at 40 ℃ for 40 hours to dry completely to prepare a film. The prepared film was stretched twice at 150 ° C., dyed for 1 minute at a concentration of 1.0 wt.% Of 40 ° C. using a direct dye (C. I. Direct Blue 71), and then stretched 2.5 times at 40 ° C. in an aqueous boric acid solution. The concentration of aqueous boric acid solution used was 3 wt.%. Measurements using an ultraviolet-visible spectrophotometer showed a polarization of 99.6% and a transmission of 40.4%. Durability test after 5 hours in high temperature wet condition (90 ℃, relative humidity: 85%) showed little change in polarization and transmittance and no change in film form.

Example 8

80 mol of water was mixed with 1 mol of alternating PVA having a number average degree of polymerization of 4,500, 99.9% of saponification, and 58% of an alternating diad group, and then completely dissolved by stirring at 90 ° C. for 1 hour. Poured into a stainless steel plate, dried under vacuum at 40 ℃ for 40 hours to dry completely to prepare a film. The prepared film was stretched twice at 150 ° C., dyed for 1 minute at a concentration of 1.0 wt.% Of 40 ° C. using a direct dye (C. I. Direct Blue 71), and then stretched 2.5 times at 40 ° C. in an aqueous boric acid solution. The concentration of aqueous boric acid solution used was 3 wt.%. Measurement using an ultraviolet-visible spectrophotometer showed a polarization of 99.6% and a transmission of 40.2%. Durability test after 5 hours in high temperature wet condition (90 ℃, relative humidity: 85%) showed little change in polarization and transmittance and no change in film form.

Example 9

80 mol of water was mixed with 1 mol of alternating PVA having a number average degree of polymerization of 4,000, a degree of saponification of 99.9%, and a content of alternating diad groups of 59%. Poured into a stainless steel plate, dried under vacuum at 40 ℃ for 40 hours to dry completely to prepare a film. The prepared film was stretched twice at 100 ° C. and dyed for 1 minute at a concentration of 1.0 wt.% At 30 ° C. using direct dye (C. I. Direct Blue 71), and then stretched 2.5 times at 40 ° C. in an aqueous boric acid solution. The concentration of aqueous boric acid solution used was 3 wt.%. Measurements using an ultraviolet-visible spectrophotometer showed a polarization of 99.3% and a transmission of 40.4%. Durability test after 5 hours in high temperature wet condition (90 ℃, relative humidity: 85%) showed little change in polarization and transmittance and no change in film form.

Example 10

80 mol of water was mixed with 1 mol of alternating PVA having a number average degree of polymerization of 3,700, saponification degree of 99.9%, and alternating diad group content of 60%. Poured into a stainless steel plate, dried under vacuum at 40 ℃ for 40 hours to dry completely to prepare a film. The prepared film was stretched twice at 150 ° C., dyed for 1 minute at a concentration of 1.0 wt.% Of 40 ° C. using a direct dye (C. I. Direct Blue 71), and stretched 2.5 times at 40 ° C. in an aqueous boric acid solution. The concentration of aqueous boric acid solution used was 3wt.%. Measurements using an ultraviolet-visible spectrophotometer showed a polarization of 99.5% and a transmission of 40.3%. Durability test after 5 hours in high temperature wet condition (90 ℃, relative humidity: 85%) showed little change in polarization and transmittance and no change in film form.

Example 11

80 mol of water was mixed with 1 mol of alternating PVA having a number average degree of polymerization of 4,500, 99.9% of saponification, and 58% of an alternating diad group, and then completely dissolved by stirring at 90 ° C. for 1 hour. Poured into a stainless steel plate, dried under vacuum at 40 ℃ for 40 hours to dry completely to prepare a film. The prepared film was stretched twice at 100 ° C., dyed for 1 minute at a concentration of 1.0 wt.% Of 40 ° C. using a direct dye (C. I. Direct Red 81), and then stretched 2.5 times at 40 ° C. in an aqueous boric acid solution. The concentration of aqueous boric acid solution used was 3 wt.%. Measurements using an ultraviolet-visible spectrophotometer showed a polarization of 99.7% and a transmission of 40.3%. Durability test after 5 hours in high temperature wet condition (90 ℃, relative humidity: 85%) showed little change in polarization and transmittance and no change in film form.

Example 12

80 mol of water was mixed with 1 mol of alternating PVA having a number average degree of polymerization of 4,500, 99.9% of saponification, and 58% of an alternating diad group, and then completely dissolved by stirring at 90 ° C. for 1 hour. Poured into a stainless steel plate, dried under vacuum at 40 ℃ for 40 hours to dry completely to prepare a film. The prepared film was stretched twice at 100 ° C., dyed for 1 minute at a concentration of 1.0 wt.% Of 40 ° C. using a direct dye (C. I. Direct Blue 71), and stretched 2.5 times at 40 ° C. in an aqueous boric acid solution. The concentration of aqueous boric acid solution used was 3 wt.%. Measurements using an ultraviolet-visible spectrophotometer showed a polarization of 99.6% and a transmission of 40.3%. Durability test after 5 hours in high temperature wet condition (90 ℃, relative humidity: 85%) showed little change in polarization and transmittance and no change in film form.

Example 13

80 mol of water was mixed with 1 mol of alternating PVA having a number-average degree of polymerization of 4,500, 99.9% of saponification, and 58% of an alternating diad group, and then completely dissolved by stirring at 90 ° C. for 1 hour. Poured into a stainless steel plate, dried under vacuum at 40 ℃ for 40 hours to dry completely to prepare a film. The prepared film was stretched twice at 150 ° C., dyed for 1 minute at a concentration of 0.7 wt.% Of 40 ° C. using a direct dye (C. I. Direct Red 81), and then stretched 2.5 times at 40 ° C. in an aqueous boric acid solution. The concentration of aqueous boric acid solution used was 3 wt.%. Measurements using an ultraviolet-visible spectrophotometer showed a polarization of 99.3% and a transmission of 40.4%. Durability test after 5 hours in high temperature wet condition (90 ℃, relative humidity: 85%) showed little change in polarization and transmittance and no change in film form.

Example 14

80 mol of water was mixed with 1 mol of alternating PVA having a number average degree of polymerization of 4,500, 99.9% of saponification, and 58% of an alternating diad group, and then completely dissolved by stirring at 90 ° C. for 1 hour. Poured into a stainless steel plate, dried under vacuum at 40 ℃ for 40 hours to dry completely to prepare a film. The prepared film was stretched twice at 150 ° C. and dyed for 1 minute at a concentration of 0.7 wt.% At 40 ° C. using direct dye (C. I. Direct Blue 71), and then stretched 2.5 times at 40 ° C. in an aqueous boric acid solution. The concentration of aqueous boric acid solution used was 3 wt.%. Measurements using an ultraviolet-visible spectrophotometer showed a polarization of 99.2% and a transmittance of 40.3%. Durability test after 5 hours in high temperature wet condition (90 ℃, relative humidity: 85%) showed little change in polarization and transmittance and no change in film form.

Example 15

80 mol of water was mixed with 1 mol of alternating PVA having a number average degree of polymerization of 4,500, 99.9% of saponification, and 58% of an alternating diad group, and then completely dissolved by stirring at 90 ° C. for 1 hour. Poured into a stainless steel plate, dried under vacuum at 40 ℃ for 40 hours to dry completely to prepare a film. The prepared film was stretched twice at 150 ° C., dyed for 1 minute and 20 seconds at a concentration of 1.0 wt.% Of 40 ° C. using a direct dye (C. I. Direct Red 81), and then stretched 2.5 times in an aqueous boric acid solution at 40 ° C. The concentration of aqueous boric acid solution used was 3 wt.%. As measured using an ultraviolet-visible spectrophotometer, the polarization was 99.8% and the transmittance was 40.1%. Durability test after 5 hours in high temperature wet condition (90 ℃, relative humidity: 85%) showed little change in polarization and transmittance and no change in film form.

Example 16

80 mol of water was mixed with 1 mol of alternating PVA having a number average degree of polymerization of 4,500, 99.9% of saponification, and 58% of an alternating diad group, and then completely dissolved by stirring at 90 ° C. for 1 hour. Poured into a stainless steel plate, dried under vacuum at 40 ℃ for 40 hours to dry completely to prepare a film. The prepared film was stretched twice at 150 ° C., dyed for 1 minute and 20 seconds at a concentration of 1.0 wt.% Of 40 ° C. using a direct dye (C. I. Direct Blue 71), and then stretched 2.5 times in an aqueous boric acid solution at 40 ° C. The concentration of aqueous boric acid solution used was 3 wt.%. Measurements using an ultraviolet-visible spectrophotometer showed a polarization of 99.7% and a transmittance of 40.1%. Durability test after 5 hours in high temperature wet condition (90 ℃, relative humidity: 85%) showed little change in polarization and transmittance and no change in film form.

Example 17

80 mol of water was mixed with 1 mol of alternating PVA having a number average degree of polymerization of 4,500, 99.9% of saponification, and 58% of an alternating diad group, and then completely dissolved by stirring at 90 ° C. for 1 hour. Poured into a stainless steel plate, dried under vacuum at 40 ℃ for 40 hours to dry completely to prepare a film. The prepared film was stretched twice at 150 ° C. and dyed for 1 minute at a concentration of 1.0 wt.% Of 40 ° C. using a direct dye (C. I. Direct Red 81), and then stretched 2.5 times at 40 ° C. in an aqueous boric acid solution. The concentration of aqueous boric acid solution used was 5 wt.%. Measurements using an ultraviolet-visible spectrophotometer showed a polarization of 99.7% and a transmission of 40.2%. Durability test after 5 hours in high temperature wet condition (90 ℃, relative humidity: 85%) showed little change in polarization and transmittance and no change in film form.

Example 18

80 mol of water was mixed with 1 mol of alternating PVA having a number average degree of polymerization of 4,500, 99.9% of saponification, and 58% of an alternating diad group, and then completely dissolved by stirring at 90 ° C. for 1 hour. Poured into a stainless steel plate, dried under vacuum at 40 ℃ for 40 hours to dry completely to prepare a film. The prepared film was stretched twice at 150 ° C., dyed for 1 minute at a concentration of 1.0 wt.% Of 40 ° C. using a direct dye (C. I. Direct Blue 71), and then stretched 2.5 times at 40 ° C. in an aqueous boric acid solution. The concentration of aqueous boric acid solution used was 5 wt.%. As measured using an ultraviolet-visible spectrophotometer, the polarization was 99.6% and the transmittance was 40.1%. Durability test after 5 hours in high temperature wet condition (90 ℃, relative humidity: 85%) showed little change in polarization and transmittance and no change in film form.

Example 19

80 mol of water was mixed with 1 mol of alternating PVA having a number average degree of polymerization of 4,500, 99.9% of saponification, and 58% of an alternating diad group, and then completely dissolved by stirring at 90 ° C. for 1 hour. Poured into a stainless steel plate, dried under vacuum at 40 ℃ for 40 hours to dry completely to prepare a film. The prepared film was stretched twice at 150 ° C., dyed for 1 minute at a concentration of 1.0 wt.% Of 30 ° C. using a direct dye (C. I. Direct Red 81), and stretched 2.5 times at 40 ° C. in an aqueous boric acid solution. The concentration of aqueous boric acid solution used was 3 wt.%. Measurement using an ultraviolet-visible spectrophotometer showed a polarization of 99.4% and a transmission of 40.6%. Durability test after 5 hours in high temperature wet condition (90 ℃, relative humidity: 85%) showed little change in polarization and transmittance and no change in film form.

Example 20

80 mol of water was mixed with 1 mol of alternating PVA having a number average degree of polymerization of 4,500, 99.9% of saponification, and 58% of an alternating diad group, and then completely dissolved by stirring at 90 ° C. for 1 hour. Poured into a stainless plate, vacuum dried for 40 hours at 40 ℃ to dry completely to prepare a film. The prepared film was stretched twice at 150 ° C., dyed for 1 minute at a concentration of 1.0 wt.% Of 30 ° C. using a direct dye (C. I. Direct Blue 71), and stretched 2.5 times at 40 ° C. in an aqueous boric acid solution. The concentration of aqueous boric acid solution used was 3 wt.%. Measurement using an ultraviolet-visible spectrophotometer showed a polarization of 99.4% and a transmission of 40.5%. Durability test after 5 hours in high temperature wet condition (90 ℃, relative humidity: 85%) showed little change in polarization and transmittance and no change in film form.

Comparative Example 1

80 mol of water was mixed with 1 mol of the hybrid array PVA having the number-average degree of polymerization of 3,500, the degree of saponification of 99.9%, and the content of the alternating diad group, 52.5%, and completely dissolved by stirring at 90 ° C. for 1 hour. Poured into a stainless steel plate, dried under vacuum at 40 ℃ for 40 hours to dry completely to prepare a film. The prepared film was stretched twice at 150 ° C. and dyed for 1 minute at a concentration of 1.0 wt.% Of 40 ° C. using a direct dye (C. I. Direct Red 81), and then stretched 2.5 times at 40 ° C. in an aqueous boric acid solution. The concentration of aqueous boric acid solution used was 3 wt.%. Measurement using an ultraviolet-visible spectrophotometer showed a polarization of 99.1% and a transmission of 40.0%. After leaving for 5 hours in a high temperature wet condition (90 ° C., relative humidity: 85%), the durability test showed a polarization degree of 97.2% and a transmittance of 42.8%, and the shape of the film was severely changed.

Comparative Example 2

80 mol of water was mixed with 1 mol of the hybrid array PVA having the number-average degree of polymerization of 1,300, the degree of saponification of 99.9%, and the content of the alternating diad group, 51.3%, and completely dissolved by stirring at 90 ° C. for 1 hour. Poured into a stainless plate, vacuum dried for 40 hours at 40 ℃ to dry completely to prepare a film. The prepared film was stretched twice at 150 ° C. and dyed for 1 minute at a concentration of 1.0 wt.% Of 40 ° C. using a direct dye (C. I. Direct Blue 71), and then stretched 2.5 times at 40 ° C. in an aqueous boric acid solution. The concentration of aqueous boric acid solution used was 3 wt.%. Measurements using an ultraviolet-visible spectrophotometer showed a polarization of 99.2% and a transmission of 40.2%. After leaving for 5 hours in a high temperature wet condition (90 ° C, relative humidity: 85%), the durability test showed a polarization degree of 95.3% and a transmittance of 44.2%.

Comparative Example 3

80 mol of water was mixed with 1 mol of hybrid PVA having a number-average degree of polymerization of 1,700 and a degree of saponification of 99.9%, and an alternating diad group content of 51.9%, and then completely dissolved by stirring at 90 ° C. for 1 hour. Poured into a stainless steel plate, dried under vacuum at 40 ℃ for 40 hours to dry completely to prepare a film. The prepared film was stretched twice at 150 ° C., dyed for 1 minute at a concentration of 1.0 wt.% Of 40 ° C. using a direct dye (C. I. Direct Blue 71), and then stretched 2.5 times at 40 ° C. in an aqueous boric acid solution. The concentration of aqueous boric acid solution used was 3 wt.%. Measurements using an ultraviolet-visible spectrophotometer showed a polarization of 99.1% and a transmission of 40.2%. After leaving for 5 hours in a high temperature wet state (90 ° C., relative humidity: 85%), the durability test showed a polarization degree of 94.1% and a transmittance of 44.5%, and the shape of the film was severely changed.

In the present invention, the durability at high temperature and high humidity is dramatically improved, the polarization effect is very excellent, the stereoregularity is high, and the alternating polyvinyl alcohol dye-based polarizing film having excellent durability even without bonding the protective film on both sides of the film. Has the effect of providing. In addition, the present invention has the effect of providing a method for producing an alternating polyvinyl alcohol dye-based polarizing film.

Simple modifications or changes of the present invention can be easily carried out by those skilled in the art, and all such modifications or changes can be seen to be included in the scope of the present invention.

Claims (8)

First stretching the alternating polyvinyl alcohol (PVA) film; The stretched film was dyed for 20 minutes or less in a salt bath at 0 to 70 DEG C with 0.01 to 5.00 wt% of a dye; And Second stretching the dyed film again; Method of producing an alternating polyvinyl alcohol dye-based polarizing film, characterized in that it is prepared in a step. The method of claim 1, wherein the alternating polyvinyl alcohol film By adding an initiator used at low temperature to polymerize vinyl acetate and / or vinyl pivalate, the number average polymerization degree is 3,600 to 22,000, the saponification degree to 90.0 to 99.9%, and the alternating diad group content is 53 to 68%. Alternating polyvinyl alcohol is prepared; And Prepared by dissolving the prepared polyvinyl alcohol in a solvent containing water, dimethyl sulfoxide, or a mixture thereof;  A method of producing an alternating polyvinyl alcohol dye-based polarizing film, characterized in that. The method of claim 1, wherein at least one of the first and second stretches is a band stretch or a wet stretch performed at a constant draw ratio at 10 to 230 ° C. 6. . The method of claim 1, wherein the second stretching is performed in an aqueous boric acid solution, a formalin aqueous solution, or a mixture thereof having a concentration of 0.1 to 10.0 wt%. The method of claim 1, wherein the second stretching is performed after washing, fixing, and drying the dyed film. The method of claim 1, wherein the dye is a direct dye. An alternating polyvinyl alcohol dye-based polarizing film, which is produced by any one of claims 1 to 6. A liquid crystal display (LCD) comprising the alternating polyvinyl alcohol dye-based polarizing film of claim 7.