KR20130030990A - Method for preparing polarizer - Google Patents

Method for preparing polarizer Download PDF

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KR20130030990A
KR20130030990A KR1020110094628A KR20110094628A KR20130030990A KR 20130030990 A KR20130030990 A KR 20130030990A KR 1020110094628 A KR1020110094628 A KR 1020110094628A KR 20110094628 A KR20110094628 A KR 20110094628A KR 20130030990 A KR20130030990 A KR 20130030990A
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South Korea
Prior art keywords
polarizer
aqueous solution
weight
film
crosslinking
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KR1020110094628A
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Korean (ko)
Inventor
이종석
김윤성
조천희
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동우 화인켐 주식회사
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Priority to KR1020110094628A priority Critical patent/KR20130030990A/en
Publication of KR20130030990A publication Critical patent/KR20130030990A/en

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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29DPRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
    • B29D11/00Producing optical elements, e.g. lenses or prisms
    • B29D11/00634Production of filters
    • B29D11/00644Production of filters polarizing
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B1/00Optical elements characterised by the material of which they are made; Optical coatings for optical elements
    • G02B1/10Optical coatings produced by application to, or surface treatment of, optical elements
    • G02B1/14Protective coatings, e.g. hard coatings
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00Optical elements other than lenses
    • G02B5/30Polarising elements
    • G02B5/3025Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state
    • GPHYSICS
    • G02OPTICS
    • G02FOPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333Constructional arrangements; Manufacturing methods
    • G02F1/1335Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/133528Polarisers

Abstract

PURPOSE: A manufacturing method of a polarizer is provided to prevent degradation after putting under dry heat condition and to improve color durability. CONSTITUTION: A transparent non-oriented polyvinyl alcoholic film is precipitated in water of 30°C for 2 minutes, swelled and is dyed after being precipitated in a 30°C aqueous solution in which 3.5 mmol/L iodine and 2 weight% potassium iodide are included for dyeing for 4 minutes. The polyvinyl alcoholic film is precipitated in a 50°C cross-linking aqueous solution in which 10 weight% potassium iodide, 3.7 weight% boric acid and 0.5 weight% magnesium acetate are included for 2 minutes and is cross-linked. A cellulose triacetate is laminated on both surface of a polarizer and a polarizer plate is manufactured.

Description

[0001] METHOD FOR PREPARING POLARIZER [0002]

The present invention relates to a method for producing a polarizer having excellent optical characteristics and preventing deterioration even after being left under dry heat and excellent in color durability.

The polarizing plate has a structure in which a transparent protective film is laminated on both sides or one side of a polarizer made of a polyvinyl alcohol-based resin in which dichroic dye is adsorbed and oriented.

The polarizer using iodine as a dichroic dye is an iodine type polarizer, and the polarizer using a dichroic dye is called a dye type polarizer. Dual iodine polarizers have high transmittance and high polarization (high contrast) compared to dye polarizers and are widely used.

However, iodine polarizers have superior optical characteristics than dye-based polarizers, but have low optical durability. For example, when the iodine polarizer or the polarizing plate including the polarizer is left under dry heat, there is a problem that the transmittance is reduced or discolored.

Moreover, in recent years, as the field of use of the liquid crystal display device is expanded and the peripheral technology is advanced, the demand for the performance of the polarizing plate is becoming more stringent. Specifically, a polarizing plate having high contrast (high transmittance and high polarization) and excellent optical durability such as heat resistance is required.

On the contrary, Japanese Patent Application Laid-Open No. 2007-122050 adds a step of impregnating zinc after dyeing, stretching, and dispersion treatment to improve the problems such as decrease in transmittance and discoloration under dry heat. However, the method requires a separate additional process, which complicates the process and thus has a disadvantage in that handleability and productivity are reduced.

In addition, Japanese Patent Application Laid-Open No. 2000-035512 discloses a method of adding zinc ions to a boric acid crosslinking bath. However, in the above method, a chemical reaction occurs between the dye solution and zinc ions, and a precipitate is generated by the chemical reaction, resulting in poor appearance, foreign matter, and fracture.

The present invention is to provide a method of manufacturing a polarizer which is prevented from deterioration and excellent in color durability after being left under dry heat.

In addition, the present invention is to provide a method of manufacturing a polarizer having excellent optical properties such as transmittance and polarization degree by preventing the leakage of the iodine complex.

In addition, the present invention is to provide a polarizing plate comprising the polarizer.

The inventors of the present invention used crosslinked aqueous solutions containing acetates, boron compounds, and iodides of certain metals to maintain optical properties such as transmittance and polarization, and to prevent deterioration after being left under dry heat. It was found that the polarizer with excellent durability can be manufactured to complete the present invention.

Accordingly, the present invention relates to acetates of at least one metal selected from the group consisting of aluminum, potassium, calcium, copper, cobalt, palladium, manganese, zirconium, magnesium, cesium, lithium, beryllium, sodium, rubidium, strontium, barium and indium, It provides a method for producing a polarizer comprising the step of immersing a polyvinyl alcohol-based film in a crosslinked aqueous solution containing a boron compound, and iodide.

Preferably the acetate of the metal may be formed of one or more metals selected from the group consisting of aluminum, magnesium, cobalt, zirconium, copper, calcium and sodium.

Acetate of the metal may contain from 0.03 to 10% by weight relative to 100% by weight of the crosslinked aqueous solution.

The boron compound may be included in an amount of 1 to 10% by weight based on 100% by weight of the crosslinking aqueous solution.

The iodide may be included in an amount of 0.05 to 15 wt% based on 100 wt% of the crosslinked aqueous solution.

Moreover, this invention provides the polarizer which is manufactured by the said manufacturing method, and the amount of change of the following A700 after leaving for 30 minutes in 105 degreeC and a dry atmosphere is 0.001-1.3.

A700 =-Log 10 {(T MD, 700 × T TD, 700 ) / 10000}

(Wherein T MD, 700 is the parallel transmittance at a wavelength of 700 nm obtained when the pair of polarizers are arranged in parallel with the absorption axis, and T TD, 700 is the state where the absorption axis is orthogonal to the pair of polarizers). Orthogonal transmittance at a wavelength of 700 nm obtained when disposed).

In addition, the present invention provides a polarizing plate in which a protective film is laminated on at least one surface of a polarizer produced by the above production method.

The polarizer according to the present invention is prevented from deterioration after being left under dry heat and excellent in color durability, which is useful for a liquid crystal display device which is likely to be exposed to high temperatures such as for cellular phones or in-vehicle vehicles.

In addition, the polarizer according to the present invention is excellent in optical properties such as transmittance and polarization degree by preventing the leakage of the iodine complex.

The present invention relates to a method for producing a polarizer having excellent optical characteristics and preventing deterioration even after being left under dry heat and excellent in color durability.

It will be described below in detail.

The polarizer manufacturing method of the present invention is a acetate of at least one metal selected from the group consisting of potassium, calcium, copper, cobalt, palladium, manganese, zirconium, magnesium, cesium, lithium, beryllium, sodium, rubidium, strontium, barium and indium, And immersing the polyvinyl alcohol-based film in a crosslinked aqueous solution containing a boron compound and an iodide.

In the present invention, the polarizer means a conventional iodine-based polarizer in which iodine is adsorbed and oriented on the polymer film.

The polymer film for preparing the polarizer is not particularly limited as long as it is a dichroic material, that is, a film that can be dyed by iodine, and specifically, a polyvinyl alcohol film, a partially gumified polyvinyl alcohol film; Hydrophilic polymer films such as polyethylene terephthalate film, ethylene-vinyl acetate copolymer film, ethylene-vinyl alcohol copolymer film, cellulose film, partially gumified film thereof and the like; Or a dehydrated polyvinyl alcohol film, a dehydrochloric acid-treated polyvinyl alcohol film, and the like. Among them, polyvinyl alcohol-based films are preferred in that they are excellent in effect of enhancing uniformity in polarization degree and excellent in dyeing affinity for iodine.

Usually, the method of manufacturing a polarizer includes a swelling step, a dyeing step, a crosslinking step, an stretching step, a washing step and a drying step, and are mainly classified by the stretching method. For example, a dry drawing method, a wet drawing method, or the hybrid drawing method which mixed the said two types of drawing methods, etc. are mentioned. Hereinafter, the manufacturing method of the polarizer of the present invention will be described using the wet stretching method as an example, but is not limited thereto.

The remaining steps except the drying step are performed in a state in which the polyvinyl alcohol film is immersed in a constant temperature bath filled with one or more kinds of solutions selected from various kinds of solutions.

In addition, the order and the number of repetition of each step are not particularly limited, and each step may be performed simultaneously or sequentially, and some steps may be omitted. For example, the stretching step may be performed before the dyeing step or after the dyeing step, and may be performed simultaneously with the swelling step or the dyeing step.

The swelling step is immersed in a swelling tank filled with an swelling aqueous solution before dyeing the unstretched polyvinyl alcohol-based film, to remove impurities such as dust and antiblocking agent deposited on the surface of the polyvinyl alcohol-based film and to remove polyvinyl alcohol It is a step for improving the physical properties of the polarizer by swelling the system film to improve the stretching efficiency and to prevent dyeing unevenness.

Water (pure water, deionized water) can usually be used as a swelling aqueous solution, and when a small amount of glycerin or potassium iodide is added thereto, the swelling of the polymer film and the processability can be improved. It is preferable that content of glycerin is 5 weight% or less with respect to 100 weight% of aqueous solutions for swelling, and content of potassium iodide is 10 weight% or less.

The swelling bath temperature is preferably 20 to 45 캜, more preferably 25 to 40 캜.

The execution time (swelling tank immersion time) of the swelling step is preferably 180 seconds or less, more preferably 90 seconds or less. When the immersion time is within the above range, it is possible to prevent the swelling from becoming excessive and saturation, to prevent breakage due to softening of the polyvinyl alcohol film and to improve the polarization degree by uniformly adsorbing iodine in the dyeing step have.

The stretching step may be carried out together with the swelling step, wherein the stretching ratio is preferably about 1.1 to 3.5 times.

The swelling step may be omitted and swelling may be performed simultaneously in the staining step.

The dyeing step is a step of adsorbing iodine to the polyvinyl alcohol-based film by immersing the polyvinyl alcohol-based film in a dye bath filled with a dichroic material, for example, an aqueous solution for dyeing containing iodine.

The dyeing aqueous solution may comprise water, a water-soluble organic solvent or a mixed solvent thereof and iodine. The content of iodine is preferably 0.4 to 400 mmol / L, more preferably 0.8 to 275 mmol / L, and most preferably 1 to 200 mmol / L with respect to 100 wt% of the aqueous solution for dyeing. In order to further improve dyeing efficiency, iodide may be further included as a dissolution aid. As the iodide, potassium iodide, lithium iodide, sodium iodide, zinc iodide, aluminum iodide, lead iodide, copper iodide, barium iodide, calcium iodide, tin iodide and titanium iodide may be used alone or in combination of two or more. Of these, potassium iodide is preferable in view of high solubility in water. The content of iodide is preferably 0.010 to 10% by weight, more preferably 0.100 to 5% by weight, based on 100% by weight of the dyeing aqueous solution.

The temperature of the dye bath is preferably 5 to 42 ° C, more preferably 10 to 35 ° C. The immersion time of the polyvinyl alcohol film in the dyeing bath is not particularly limited, and is preferably 1 to 20 minutes, and more preferably 2 to 10 minutes.

The dyeing step and the stretching step may be carried out. In this case, the cumulative stretching ratio is preferably 1.1 to 4.0 times. In this specification, "cumulative draw ratio" represents the value of the product of draw ratios in each step.

The crosslinking step is a step of fixing the adsorbed iodine molecules by immersing the dyed polyvinyl alcohol-based film in an aqueous solution for crosslinking so that the dyeability by physically adsorbed iodine molecules is not lowered by the external environment. Dichroic dyes are not often eluted in a humid environment, but iodine is often dissolved or sublimed depending on the environment when the crosslinking reaction is unstable, and sufficient crosslinking reaction is required. In addition, in order to orient all polyvinyl alcohol molecules and iodine molecules located between the molecules to improve optical properties, the crosslinking step is important because it generally has to be drawn at the largest draw ratio in the crosslinking step.

The present invention provides a crosslinked aqueous solution containing acetates of at least one metal selected from the group consisting of potassium, calcium, copper, cobalt, palladium, manganese, zirconium, magnesium, cesium, lithium, beryllium, sodium, rubidium, strontium, barium and indium. Use When the polyvinyl alcohol film obtained by dyeing the metal acetate in the crosslinking aqueous solution is immersed, a chelate structure is formed between the metal acetate and polyvinyl alcohol, and the degree of crosslinking is improved, and the hydroxyl group of the acetate group and the polyvinyl alcohol ( A dehydration reaction is formed between the -OH) groups to improve the crosslinking efficiency. If the degree of crosslinking and crosslinking efficiency is improved, deterioration (redding) is prevented even after being left under dry heat, and appearance defects are reduced, and leakage of iodine complex (combination of polyvinyl alcohol and polyvalent iodine ion) is prevented to prevent polarizer and polarizer having excellent durability. Can be prepared.

The crosslinked aqueous solution may include water as a solvent, a boron compound such as boric acid and sodium borate, an iodide, and an acetate of the metal, and may further include an organic solvent that is mutually soluble with water.

The boron compound imparts short crosslinking and rigidity to suppress wrinkling during processing, thereby improving handling properties and forming iodine alignment.

It is preferable that content of a boron compound is 1 to 10 weight% with respect to 100 weight% of crosslinking aqueous solution, More preferably, it is 2 to 6 weight%. If the content is less than 1% by weight, the crosslinking effect of the boron compound is reduced, and thus it is difficult to impart rigidity. If the content is more than 10% by weight, the crosslinking reaction of the inorganic crosslinking agent is excessively activated, so that the crosslinking reaction of the organic crosslinking agent is difficult to proceed effectively.

Iodide is used to prevent the uniformity of the degree of polarization in the plane of polarizers and the desorption of dyed iodine. The iodide may be the same as that used in the dyeing step, the content may be 0.05 to 15% by weight relative to 100% by weight of the crosslinking aqueous solution, preferably 0.5 to 11% by weight. If the content is less than 0.05% by weight, the iodide ion in the film may escape to increase the transmittance and the color value of the polarizer may change, There is a problem that the transmittance is reduced.

The acetate of the metal may be formed of one or more metals selected from the group consisting of aluminum, potassium, calcium, copper, cobalt, palladium, manganese, zirconium, magnesium, cesium, lithium, beryllium, sodium, rubidium, strontium, barium and indium. have. In consideration of the dual process handleability and productivity, it is preferable to be formed of at least one metal selected from the group consisting of aluminum, magnesium, cobalt, zirconium, copper, calcium and sodium. The content may be 0.03 to 10% by weight relative to 100% by weight of the crosslinked aqueous solution, preferably 0.05 to 7% by weight. If the content is less than 0.03% by weight, the formation of chelating structure between the metal and polyvinyl alcohol is insufficient, which prevents deterioration due to acetate salts and excellent color durability. There is a problem that breakage and productivity are lowered.

The temperature of the crosslinking bath is 20 to 70 캜, and the immersion time of the polyvinyl alcohol film in the crosslinking bath may be 1 second to 15 minutes, preferably 5 seconds to 10 minutes.

The stretching step may be performed together with the crosslinking step, in which case it is preferable that the stretching is performed such that the total cumulative stretching ratio is 3.0 to 8.0 times.

As described above, the stretching step may be carried out with the swelling step, the dyeing step, the crosslinking step, and may be carried out as an independent stretching step using a separate stretching tank filled with the running aqueous solution after the crosslinking step.

The washing step is a step of removing the unnecessary residue such as boric acid attached to the polyvinyl alcohol-based film in the previous steps by immersing the polyvinyl alcohol-based film cross-linked and stretched in a washing tank filled with aqueous solution for washing.

The aqueous solution for washing may be water, and further iodide may be added thereto.

It is preferable that the temperature of a water washing tank is 10-60 degreeC, More preferably, it is 15-40 degreeC.

The washing step may be omitted and may be performed whenever previous steps such as dyeing step, crosslinking step or stretching step are completed. In addition, it may be repeated one or more times, and the number of repetitions is not particularly limited.

The drying step is a step of obtaining a polarizer having excellent optical properties by drying the washed polyvinyl alcohol-based film and further improving the orientation of the iodine molecules dyed by neck-in by drying.

As the drying method, natural drying, air drying, heat drying, far infrared drying, microwave drying, hot air drying, etc. may be used. Recently, microwave drying, which activates and dries only water in a film, is newly used. Drying is mainly used. For example, hot air drying may be performed at 20 to 90 ° C. for 1 to 10 minutes. The drying temperature is preferably low in order to prevent deterioration of the polarizer, more preferably 80 ° C. or less, and most preferably 60 ° C. or less.

The present invention provides a polarizer manufactured by the above method. The polarizer is in the range of 0.001 to 1.3 in the amount of change in the following A700 before and after leaving for 30 minutes at 105 ° C in a dry atmosphere.

A700 =-Log 10 {(T MD, 700 × T TD, 700 ) / 10000}

(Wherein T MD, 700 is the parallel transmittance at a wavelength of 700 nm obtained when the pair of polarizers are arranged in parallel with the absorption axis, and T TD, 700 is the state where the absorption axis is orthogonal to the pair of polarizers). Orthogonal transmittance at a wavelength of 700 nm obtained when disposed).

In addition, the present invention provides a polarizing plate in which a protective film is laminated on at least one surface of the polarizer manufactured by the manufacturing method.

The protective film is not particularly limited as long as it is a film excellent in transparency, mechanical strength, thermal stability, moisture barrier property, isotropy, and the like. Specifically, polyester resins such as polyethylene terephthalate, polyethylene isophthalate and polybutylene terephthalate; Cellulose-based resins such as diacetylcellulose and triacetylcellulose; Polycarbonate resin; Acrylic resins such as polymethyl (meth) acrylate and polyethyl (meth) acrylate; Styrene resins such as polystyrene and acrylonitrile-styrene copolymer; Polyolefin resins such as polyethylene, polypropylene, cyclo- or norbornene-structured polyolefins, and ethylene propylene copolymers; Vinyl chloride resin; Polyamide resins such as nylon and aromatic polyamide; Imide resin; Polyether sulfone type resin; Sulfone resins; Polyether ketone resins: sulfide polyphenylene resins; Vinyl alcohol-based resins; Vinylidene chloride resins; Vinyl butyral resin; Allylate series resin; Polyoxymethylene type resin; Epoxy resin, and the like, and a film composed of the blend of the thermoplastic resin may also be used. Moreover, you may use the film which consists of thermosetting resins or ultraviolet curable resins, such as (meth) acrylic-type, urethane type, epoxy type, and silicone type. Among them, a cellulose-based film having a surface saponified (saponified) by alkali or the like is preferable in consideration of polarization characteristics or durability. In addition, the protective film may have a function of the following optical layer.

In the present invention, the structure of the polarizing plate is not particularly limited, and various kinds of optical layers capable of satisfying required optical properties may be laminated on the polarizer. For example, a structure in which a protective film for protecting the polarizer is laminated on at least one surface of the polarizer; A structure in which a surface treatment layer such as a hard coating layer, an antireflection layer, an anti-sticking layer, a diffusion preventing layer, an anti-glare layer, or the like is laminated on at least one surface or a protective film of the polarizer; It may have a structure in which an alignment liquid crystal layer or another functional film for compensating a viewing angle is laminated on at least one surface or a protective film of the polarizer. In addition, a phase difference including a wavelength plate (including a λ plate) such as an optical film, a reflector, a semi-transmissive plate, a 1/2 wave plate, or a quarter wave plate, such as a polarization conversion device used to form various image display devices At least one of the plate, the viewing angle compensation film, and the brightness enhancement film may be laminated with an optical layer. In more detail, a polarizing plate having a structure in which a protective film is laminated on one surface of a polarizer, the polarizing plate having a reflector or a transflective reflector laminated on a laminated protective film; An oval or circular polarizing plate in which retardation plates are stacked; A wide viewing angle polarizer on which a viewing angle compensation layer or a viewing angle compensation layer is stacked; Or the polarizing plate in which the brightness improving film was laminated | stacked is preferable.

Such a polarizing plate can be applied to various image display devices such as electroluminescent display devices, plasma display devices, and field emission display devices as well as ordinary liquid crystal display devices.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention. Such variations and modifications are intended to be within the scope of the appended claims.

Example 1

A transparent unstretched polyvinyl alcohol film (VF-PS, KURARAY) having a degree of saponification of 99.9% or more was swelled by immersion in water (deionized water) at 30 ° C. for 2 minutes, and then 3.5 mmol / L of iodine and 2 wt% of potassium iodide It was dyed by immersion for 4 minutes in an aqueous solution for dyeing at 30 ℃ containing. At this time, the stretching ratio was 1.3 times and 1.4 times in the swelling and dyeing step, respectively. Subsequently, it was crosslinked by dipping for 2 minutes in an aqueous solution for crosslinking at 50 ° C. containing 10% by weight of potassium iodide, 3.7% by weight of boric acid, and 0.5% by weight of magnesium acetate. At this time, the crosslinking step was such that the total cumulative stretching ratio is 5.8 times. After the crosslinking was completed, the polyvinyl alcohol film was dried in an oven at 70 DEG C for 4 minutes to prepare a polarizer.

A triacetylcellulose (TAC) film was laminated on both sides of the prepared polarizer to prepare a polarizing plate.

Example 2

The polarizer was prepared in the same manner as in Example 1, using an aqueous solution for crosslinking containing 1 wt% of magnesium acetate.

Example 3

The polarizer was prepared in the same manner as in Example 1, using an aqueous solution for crosslinking containing 3% by weight of magnesium acetate.

Example 4

The polarizer was prepared in the same manner as in Example 1, using an aqueous solution for crosslinking containing 5% by weight of magnesium acetate.

Example 5

The polarizer was prepared in the same manner as in Example 1, using an aqueous solution for crosslinking containing 8% by weight of magnesium acetate.

Example 6

The polarizer was prepared in the same manner as in Example 1, using an aqueous solution for crosslinking containing 3% by weight of aluminum acetate.

Example 7

The polarizer was prepared in the same manner as in Example 1, using an aqueous solution for crosslinking containing 3% by weight of cobalt acetate.

Example 8

The polarizer was prepared in the same manner as in Example 1, using an aqueous solution for crosslinking containing 3% by weight of zirconium acetate.

Example 9

The polarizer was prepared in the same manner as in Example 1, using an aqueous solution for crosslinking containing 3% by weight of copper acetate.

Comparative Example 1

The polarizer was prepared in the same manner as in Example 1, using an aqueous solution for crosslinking containing 10 wt% of potassium iodide and 3.7 wt% of boric acid.

Comparative Example 2

The polarizer was prepared in the same manner as in Example 1, using a crosslinking aqueous solution containing 10% by weight of potassium iodide, 3.7% by weight of boric acid, and 0.5% by weight of zinc chloride.

Test Example

The physical properties of the polarizers prepared in the above Examples and Comparative Examples were measured by the following methods, and the results are shown in Table 1 below.

1. Optical characteristics (polarization, transmittance)

After cutting the prepared polarizer into 4 cm x 4 cm size, the transmittance was measured using an ultraviolet visible light spectrometer (V-7100, manufactured by JASCO). At this time, the polarization degree is defined by the following equation (1).

Figure pat00001

(Wherein T 1 is the parallel transmittance obtained when the pair of polarizers are arranged in parallel with the absorption axis, and T 2 is the orthogonal transmittance obtained when the pair of polarizers are arranged in the state where the absorption axes are orthogonal) .

2. Evaluation of durability (ΔA700, Δorthogonal b, ΔE )

The spectral transmittance? (?) Of the polarizer was measured using a spectrophotometer (V7100, manufactured by Nippon Bunko KK). An orthogonal spectral transmittance spectrum was obtained from the measured spectral transmittance? (?), And an A700 was determined from the spectral transmittance spectrum using an orthogonal color b and the following formula (2).

Thereafter, the polarizer was allowed to stand in a dry atmosphere at 105 캜 for 30 minutes (durability test), and the spectral transmittance τ (λ) was measured again. The orthogonal spectral transmittance spectrum was obtained from the measured spectral transmittance τ A700 was obtained from the spectrum using the orthogonal color b and the following equation 2 to determine the difference between the orthogonal color b before and after the durability test as? Orthogonal b, and the difference between before and after the durability test of A700 as? A700. At this time, it is judged that the larger the Δ orthogonal b and the ΔA 700 value, the greater the discoloration degree under dry heat.

Figure pat00002

(Wherein T MD, 700 is the parallel transmittance at a wavelength of 700 nm obtained when the pair of polarizers are arranged in parallel with the absorption axis, and T TD, 700 is the state where the absorption axis is orthogonal to the pair of polarizers). Orthogonal transmittance at a wavelength of 700 nm obtained when disposed)

In addition, the difference before and after an endurance test was made into (DELTA) E using the orthogonal L, orthogonal a, and orthogonal b value obtained from the spectral transmission spectrum, and following formula (3).

Figure pat00003

Where L 0 is the pre-endurance orthogonal L value, L 1 is the post-endurance orthogonal L value, a 0 is the pre-endurance orthogonal a value, a 1 is the post-endurance orthogonal a value, and b 0 is the pre-endurance orthogonal b value, b 1 is the orthogonal b value after endurance)

The smaller the degree of discoloration, the smaller the ΔA700 is below 1.3, the Δorthogonal b is smaller than 0.3, and the smaller ΔE is.

After standing for 30 minutes in the dry atmosphere at 105 캜, it was confirmed by visual observation whether or not the polarizer was generated.

division Transmittance (%) Polarization degree (%) △ A700 △ Ortho b ΔE Redness Etc Example 1 41.7 99.9942 1.18 0.20 0.37 radish - Example 2 41.6 99.9948 1.03 0.16 0.38 radish - Example 3 41.5 99.9947 0.95 0.12 0.24 radish - Example 4 41.6 99.9951 0.81 0.06 0.09 radish - Example 5 41.4 99.9960 0.80 0.07 0.07 radish - Example 6 41.4 99.9940 1.00 0.14 0.21 radish - Example 7 41.7 99.9944 0.99 0.21 0.30 radish - Example 8 41.8 99.9939 1.18 0.24 0.38 radish - Example 9 41.6 99.9948 1.05 0.22 0.31 radish - Comparative Example 1 41.6 99.9945 2.02 0.38 0.50 U - Comparative Example 2 41.4 99.991 2.23 0.45 0.61 U Precipitation occurrence

As shown in the above table, Examples 1 to 9, in which a polarizer was prepared by containing an acetate salt of a specific metal in a crosslinked aqueous solution according to the present invention, were deteriorated after being left to dry while maintaining optical properties (polarization and transmittance) equal to or higher than the conventional one. Was prevented and the color durability was excellent.

However, in Comparative Example 1, which did not contain a metal acetate, and Comparative Example 2, which contained zinc chloride, redness occurred, and in Comparative Example 2, precipitation occurred.

Claims (7)

Acetates, boron compounds, and iodine of at least one metal selected from the group consisting of aluminum, potassium, calcium, copper, cobalt, palladium, manganese, zirconium, magnesium, cesium, lithium, beryllium, sodium, rubidium, strontium, barium and indium A method of manufacturing a polarizer comprising immersing a polyvinyl alcohol-based film in a crosslinked aqueous solution containing a cargo.
The method of claim 1, wherein the acetate of the metal is formed of at least one metal selected from the group consisting of aluminum, magnesium, cobalt, zirconium, copper, calcium and sodium.
The method according to claim 1, wherein the acetate of the metal is contained 0.03 to 10% by weight relative to 100% by weight of the crosslinked aqueous solution.
The method of claim 1, wherein the boron compound is included in an amount of 1 to 10 wt% based on 100 wt% of the crosslinked aqueous solution.
The method of claim 1, wherein the iodide is included in an amount of 0.05 to 15 wt% based on 100 wt% of the crosslinked aqueous solution.
The polarizer manufactured by the manufacturing method of any one of Claims 1-5 and whose change amount of the following A700 after leaving for 30 minutes in 105 degreeC and a dry atmosphere is 0.001-1.3:
A700 =-Log 10 {(T MD, 700 × T TD, 700 ) / 10000}
(Wherein T MD, 700 is the parallel transmittance at a wavelength of 700 nm obtained when the pair of polarizers are arranged in parallel with the absorption axis, and T TD, 700 is the state where the absorption axis is orthogonal to the pair of polarizers). Orthogonal transmittance at a wavelength of 700 nm obtained when disposed).
A polarizing plate in which a protective film is laminated on at least one surface of a polarizer produced by the manufacturing method according to any one of claims 1 to 5.

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20150008681A (en) * 2013-07-15 2015-01-23 동우 화인켐 주식회사 Preparing method for polarizer
KR20150052777A (en) 2013-11-06 2015-05-14 동우 화인켐 주식회사 Process for Preparing Polarizer
KR20160054229A (en) 2014-11-06 2016-05-16 동우 화인켐 주식회사 Process for Preparing Polarizer
KR20210069893A (en) 2019-12-04 2021-06-14 동우 화인켐 주식회사 Process for Preparing Polarizer

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20150008681A (en) * 2013-07-15 2015-01-23 동우 화인켐 주식회사 Preparing method for polarizer
KR20150052777A (en) 2013-11-06 2015-05-14 동우 화인켐 주식회사 Process for Preparing Polarizer
KR20160054229A (en) 2014-11-06 2016-05-16 동우 화인켐 주식회사 Process for Preparing Polarizer
KR20210069893A (en) 2019-12-04 2021-06-14 동우 화인켐 주식회사 Process for Preparing Polarizer

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