KR20170081022A - Polarizing plate having an improved reliable property and high degree of polarization and method for preparing the same - Google Patents
Polarizing plate having an improved reliable property and high degree of polarization and method for preparing the same Download PDFInfo
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- KR20170081022A KR20170081022A KR1020150191697A KR20150191697A KR20170081022A KR 20170081022 A KR20170081022 A KR 20170081022A KR 1020150191697 A KR1020150191697 A KR 1020150191697A KR 20150191697 A KR20150191697 A KR 20150191697A KR 20170081022 A KR20170081022 A KR 20170081022A
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/30—Polarising elements
- G02B5/3025—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state
- G02B5/3033—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state in the form of a thin sheet or foil, e.g. Polaroid
- G02B5/3041—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state in the form of a thin sheet or foil, e.g. Polaroid comprising multiple thin layers, e.g. multilayer stacks
- G02B5/305—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state in the form of a thin sheet or foil, e.g. Polaroid comprising multiple thin layers, e.g. multilayer stacks including organic materials, e.g. polymeric layers
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C55/00—Shaping by stretching, e.g. drawing through a die; Apparatus therefor
- B29C55/02—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C55/00—Shaping by stretching, e.g. drawing through a die; Apparatus therefor
- B29C55/02—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets
- B29C55/04—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets uniaxial, e.g. oblique
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
- C08J5/18—Manufacture of films or sheets
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K5/00—Use of organic ingredients
- C08K5/0008—Organic ingredients according to more than one of the "one dot" groups of C08K5/01 - C08K5/59
- C08K5/0016—Plasticisers
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L1/00—Compositions of cellulose, modified cellulose or cellulose derivatives
- C08L1/08—Cellulose derivatives
- C08L1/10—Esters of organic acids, i.e. acylates
Abstract
The present invention relates to a polarizing plate in which polarizing plate protective films A and B sandwiching a polarizing film are sandwiched and the polarizing plate protective film B contains an asymmetric ester compound containing an aromatic group represented by the following formula A cellulose-based polarizer excellent in reliability of polarization degree having a degree of polarization of 99.9500% or more and a manufacturing method thereof.
[Chemical Formula 1]
T + [D + P] n + D
T is a residue of a toluic acid or a benzenecarboxylic acid residue, D is a propyleneglycol having 2 to 8 carbon atoms, neopentylglycol, diethyleneglycol, dipropyleneglycol Triethylene glycol, an alkylene glycol residue having 2 to 12 carbon atoms, an aryl glycol residue having 6 to 12 carbon atoms, or an oxyalkylene glycol residue having 4 to 12 carbon atoms, P is a phthalic acid having 2 to 10 carbon atoms Phthalic acid residue, an alkylene dicarboxylic acid residue having 4 to 12 carbon atoms, or an aryl dicarboxylic acid residue having 6 to 12 carbon atoms, and n represents an integer of 1 or more.
Description
The present invention relates to a cellulose-based polarizer excellent in reliability of polarization and a method for producing the same. More specifically, the present invention relates to a polarizing plate protective film comprising an asymmetric ester-based compound having an aromatic structure represented by the following formula (1), whereby the polarizing plate has a polarization degree of 99.9500% A cellulose-based polarizer and a method for producing the same.
[Chemical Formula 1]
T + [D + P] n + D
T is a residue of a toluic acid or a benzenecarboxylic acid residue, D is a propyleneglycol having 2 to 8 carbon atoms, neopentylglycol, diethyleneglycol, dipropyleneglycol Triethylene glycol, an alkylene glycol residue having 2 to 12 carbon atoms, an aryl glycol residue having 6 to 12 carbon atoms, or an oxyalkylene glycol residue having 4 to 12 carbon atoms, P is a phthalic acid having 2 to 10 carbon atoms Phthalic acid residue, an alkylene dicarboxylic acid residue having 4 to 12 carbon atoms, or an aryl dicarboxylic acid residue having 6 to 12 carbon atoms, and n represents an integer of 1 or more.
Recently, a liquid crystal display (LCD) has been used in various fields, so that it is desired to have high visibility when viewing an image. In particular, a polarizing plate or a retardation plate used in an LCD is required to have high flatness such as glass, . Also, in an LCD used in outdoor such as a car navigation system or a PDA, it is necessary to incorporate an ultraviolet absorber into a polarizing plate protective film in order to prevent deterioration of the polarizer.
In particular, a film used for the outermost surface due to the spread of a large-area television or a large-area monitor is required to have a high planarity and a high image quality, and defects such as spot defects become image defects, leading to deterioration of LCD quality. In addition, although cellulose triacetate (TAC) films are mainly used as protective films for polarizers currently used in LCDs, there is a problem that films used in LCDs tend to stick to each other due to their transparency and smoothness. Therefore, in order to improve the handling properties during film formation of these resin films and the surface treatment of these resin films, fine particles are added to the film to provide lubricity without impairing the transparency of the film, thereby improving handleability and stabilizing the winding property .
The cellulose ester film is usually produced by a solution casting film-forming method. Namely, a film is produced by softening a dope (thickened solution) of a cellulose ester from a flexible die on an endless support, releasing the self-supporting property of the dope, and peeling off the endless support. This film often contains additives such as fine particles, a plasticizer, and an ultraviolet absorber in addition to the cellulose ester. The fine particles are used for ease of lubrication and adhesion resistance of the film thus formed, and the ultraviolet absorber is used, for example, to prevent deterioration of the polarizing plate when used in a polarizing plate. These components are usually mixed together when preparing the dope.
However, the conventional cellulose-based polarizing plate is poor in resistance to high temperature and high humidity environments, and the polarization degree of the polarizing plate is lowered when exposed to a high-temperature and high-humidity reliability environment, thereby lowering the LCD contrast ratio (Contrast Ratio) .
SUMMARY OF THE INVENTION Accordingly, the present invention has been made to solve the above-mentioned problems occurring in the prior art, and it is an object of the present invention to provide a cellulose-based polarizing plate having excellent polarization reliability and a manufacturing method thereof.
The cellulose-based polarizer having excellent reliability of polarization degree according to one embodiment of the present invention,
A polarizing plate protective film A having a film thickness of 20 to 100 占 퐉 containing a cellulose ester,
An in-plane retardation Ro defined by the following formula (1) having a film thickness of 20 to 60 占 퐉 and containing cellulose ester having an acyl group total degree of substitution of 2.10 to 2.70 at 20 占 폚 to 55 nm , A polarizing plate protective film B also serving as a retardation plate having a thickness direction retardation Rth of 100 to 300 nm under the conditions of 23 DEG C and 55% RH,
A polarizing plate having a film thickness of 60 to 160 占 퐉 sandwiched between polarizers,
Wherein the polarizing plate protective film B comprises an asymmetric ester compound having an aromatic group represented by the following formula 1 and is allowed to stand in a high temperature and high humidity chamber for 60 hours in a reliability environment of 60 ° C and 90% RH for 500 hours, 2 has a polarization degree of 99.9500% or more.
[Chemical Formula 1]
T + [D + P] n + D
T is a residue of a toluic acid or a benzenecarboxylic acid residue, D is a propyleneglycol having 2 to 8 carbon atoms, neopentylglycol, diethyleneglycol, dipropyleneglycol Triethylene glycol, an alkylene glycol residue having 2 to 12 carbon atoms, an aryl glycol residue having 6 to 12 carbon atoms, or an oxyalkylene glycol residue having 4 to 12 carbon atoms, P is a phthalic acid having 2 to 10 carbon atoms Phthalic acid residue, an alkylene dicarboxylic acid residue having 4 to 12 carbon atoms, or an aryl dicarboxylic acid residue having 6 to 12 carbon atoms, and n represents an integer of 1 or more.
[Equation 1]
Ro = (nx-ny) xd
Rth = {(nx + ny) / 2-nz} xd
Ny is the maximum refractive index in the vertical direction in the film plane and nz is the maximum refractive index in the thickness direction of the film and is 23 DEG C and 55% RH, respectively, where d is the film thickness (nm), nx is the maximum refractive index in the horizontal direction in the film plane, Under the environment at a wavelength of 550 nm.
&Quot; (2) "
Polarization degree (PE) = [(Tp-Tc) / (Tp + Tc)] 1/2 x 100 (%)
Herein, Tp is the transmittance of the polarizing plate in the state where the transmission axes thereof are parallel to each other, and Tc is the transmittance of light of 400 nm to 700 nm in full-wavelength visible light under an environment of 23 DEG C and 55% RH in an orthogonal state.
According to the present invention, as the cellulose ester polarizer protective film A, cellulose triacetate having an acetyl group total substitution degree of 2.7 or more is preferable.
According to the present invention, it is preferable that the polarizer has polyvinyl alcohol and the film thickness is 3 to 30 占 퐉.
In the cellulose-based polarizing plate according to the present invention, the polarizing plate protective film B contains an asymmetric ester-based compound containing an aromatic group represented by the above formula (1).
1 is a schematic view of an apparatus for producing a general cellulose ester optical film.
2 is an exploded perspective view of polarizer lamination.
The cellulose-based polarizing plate excellent in reliability of polarization degree according to one embodiment of the present invention is characterized by including a polarizing plate protective film A (123 in FIG. 2) having a film thickness of 20 to 100 占 퐉 and containing cellulose ester, Polarizing plate protective film B (121 in Fig. 2) is sandwiched between polarizers (122 in Fig. 2, PVA film).
More specifically, the polarizing plate according to the present invention comprises a polarizing plate protective film A having a film thickness of 20 to 100 占 퐉 containing a cellulose ester,
An in-plane retardation Ro defined by the following formula (1) having a film thickness of 20 to 60 占 퐉 and containing cellulose ester having an acyl group total degree of substitution of 2.10 to 2.70 at 20 占 폚 to 55 nm , And the polarizing plate protective film B also serving as a retardation plate having a thickness of 100 to 300 nm under conditions of a retardation Rth in the thickness direction of 23 DEG C and 55% RH has a thickness of 60 to 160 mu m sandwiching the polarizer.
In the present invention, the cellulose ester polarizing plate protective film A is preferably cellulose triacetate having an acetyl group total degree of substitution of 2.7 or more, and the polarizer preferably has polyvinyl alcohol and has a film thickness of 3 to 30 μm, The protective film B includes an asymmetric ester-based compound containing an aromatic group represented by the following formula (1).
[Equation 1]
Ro = (nx-ny) xd
Rth = {(nx + ny) / 2-nz} xd
Ny is the maximum refractive index in the vertical direction in the film plane and nz is the maximum refractive index in the thickness direction of the film and is 23 DEG C and 55% RH, respectively, where d is the film thickness (nm), nx is the maximum refractive index in the horizontal direction in the film plane, Under the environment at a wavelength of 550 nm.
[Chemical Formula 1]
T + [D + P] n + D
T is a residue of a toluic acid or a benzenecarboxylic acid residue, D is a propyleneglycol having 2 to 8 carbon atoms, neopentylglycol, diethyleneglycol, dipropyleneglycol Triethylene glycol, an alkylene glycol residue having 2 to 12 carbon atoms, an aryl glycol residue having 6 to 12 carbon atoms, or an oxyalkylene glycol residue having 4 to 12 carbon atoms, P is a phthalic acid having 2 to 10 carbon atoms Phthalic acid residue, an alkylene dicarboxylic acid residue having 4 to 12 carbon atoms, or an aryl dicarboxylic acid residue having 6 to 12 carbon atoms, and n represents an integer of 1 or more.
The polarizing plate according to the present invention has a degree of polarization of 99.9500% or more expressed by the following formula (2) after being left in a high-temperature and high-humidity chamber for 60 hours in a reliability environment of 60 ° C and 90% RH.
&Quot; (2) "
Polarization degree (PE) = [(Tp-Tc) / (Tp + Tc)] 1/2 x 100 (%)
Herein, Tp is the transmittance of the polarizing plate in the state where the transmission axes thereof are parallel to each other, and Tc is the transmittance of light of 400 nm to 700 nm in full-wavelength visible light under an environment of 23 DEG C and 55% RH in an orthogonal state.
The method for producing the polarizing plate according to one embodiment of the present invention is not particularly limited, and can be manufactured by a general method. It is preferable that the back side of the cellulose ester film of the present invention is subjected to alkali saponification treatment and the treated cellulose ester film is immersed and stretched in an iodine solution to be bonded to at least one side of the polarizing film using a fully saponified polyvinyl alcohol aqueous solution . The cellulose ester film of the present invention may also be used on the other side, and another polarizing plate protective film may be used.
A polarizing film as a main component of the polarizing plate is an element that allows only light of a polarization plane in a certain direction to pass therethrough. A typical polarizing film currently known is a polyvinyl alcohol (PVA) polarizing film. This is a method of dyeing a polyvinyl alcohol film with iodine And dyed dichromatic dyes. The polarizing film is obtained by forming a film of a polyvinyl alcohol aqueous solution, uniaxially stretching the film, dyeing or dyeing it, uniaxially stretching it, and then durably treating it with a boron compound. The film thickness of such a polarizing film is 3 to 30 탆. A polarizing plate can be formed by bonding one side of the cellulose ester film of the present invention to the surface of the polarizing film. Preferably, it can be bonded by an aqueous adhesive mainly composed of completely saponified polyvinyl alcohol or the like.
The cellulose ester film of the polarizing plate protective film A is preferably cellulose triacetate having an acetyl group total degree of substitution of 2.7 or more, and is preferably a cellulose solution containing triacetyl cellulose as a basic component, an ultraviolet absorber solution, a dilute cellulose The solution is mixed to prepare a casting stock solution, which is extruded, drawn and dried in the form of a sheet to form a film having a thickness of 20 to 100 탆.
More specifically, the cellulose solution is prepared by mixing 10 to 20 parts by weight of triacetylcellulose, 80 to 90 parts by weight of a mixed solvent obtained by mixing methylene chloride and methanol in a weight ratio of 9: 1, adding triphenylphosphate (TPP) and ethylphthalylethyl And 1 to 3 parts by weight of a plasticizer mixed with glycerol (EPEG) in a weight ratio of 3: 1. The ultraviolet absorber solution can be prepared, for example, by mixing Tinuvin 328 (manufactured by Ciba Specialty Chemicals) and Tinuvin 326 6 to 9 parts by weight of a mixed ultraviolet ray absorbent mixed in a ratio of 4: 1 in weight ratio and 90 to 95 parts by weight of a mixed solvent obtained by mixing methylene chloride and methanol in a weight ratio of 9: 1 . Further, in a dilute cellulose agarose solution containing the metal oxide is 9 for the cellulose solution of 25 to 35 parts by weight of silica (SiO 2) 1 to 2 parts by weight of methylene chloride and methanol in a weight ratio: a mixture solvent mixed with 160 To 80 parts by weight may be mixed to prepare a dilute cellulose solution containing silica (metal oxide).
A method for producing the cellulose ester film of the polarizing plate protective film A is as follows. 85 to 95 parts by weight of the cellulose solution, 3 to 5 parts by weight of a dilute cellulose solution containing the metal oxide and 2 to 5 parts by weight of the ultraviolet absorber solution are mixed to prepare a casting solution, In the form of extrusion. Next, the solvent of the casting stock solution is evaporated, followed by stretching and drying to form a cellulose film having a thickness in the range of 20 to 100 mu m.
The cellulose ester film of the polarizing plate protective film B according to one embodiment of the present invention is a cellulose ester film comprising 10 to 30 parts by weight of a cellulose ester having an acyl group total substitution degree of 2.10 to 2.70 and an asymmetric ester 2 to 8 parts by weight of a plasticizer, 70 to 90 parts by weight of a mixed solvent of methylene chloride and methanol in a weight ratio of 9: 1 are mixed to prepare a dilute cellulose solution containing silica as a metal oxide.
Next, 2 to 10 parts by weight of the particulate additive liquid is added to 100 parts by weight of the main dope solution, and then the mixture is uniformly softened on a support by using a belt softener, and the solvent is evaporated, followed by stretching and drying. Can be prepared.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view of a film production apparatus which can be used for producing a cellulose ester film having an acetyl group, a propionyl group and a butyl group according to the present invention.
1, the entire process for producing such a cellulose ester film is shown. The main dope liquid is extruded onto the surface of the
The die 10 can be a conventional T-die, and the
The polarizing plate protective film B produced by the above method also serves as a retardation plate. The in-plane retardation Ro defined by the above-mentioned formula (1) is 20 to 100 nm under the conditions of 23 캜 and 55% RH, the retardation Rth in the thickness direction Lt; 0 > C and 55% RH.
The cellulose esters can be generally used alone or in combination with cellulose esters synthesized from cellulose ester synthesized from linter pulp, wood pulp and kenaf pulp, and other raw materials.
According to the present invention, the cellulose ester optical film may contain a specific plasticizer, and the plasticizer is an asymmetric ester plasticizer containing an aromatic group represented by the general formula (1). The cellulose ester film may be a barrier film of a cellulose ester film before / And is particularly preferable in setting the characteristics to a predetermined range.
Specific compounds of the aromatic-containing asymmetric ester compound according to the present invention are as follows, but the present invention is not limited thereto.
(2)
Mw = 400.4
(3)
Mw = 456.5
[Chemical Formula 4]
Mw = 460.5
[Chemical Formula 5]
Mw = 516.6
[Chemical Formula 6]
Mw = 548.6
(7)
Mw = 606.6
[Chemical Formula 8]
Mw = 690.8
[Chemical Formula 9]
Mw = 696.7
[Chemical formula 10]
Mw = 780.9
(11)
Mw = 828.9
According to the present invention, the polarizing plate can be produced by the following method. The
More specifically, a step of obtaining a saponified cellulose ester film on the side bonded to the polarizer (first step); Immersing the polarizing film in a polyvinyl alcohol adhesive tank (second step); A step of lightly wiping off excess adhesive adhered to the polarizing film in the step 2, placing the cellulose ester film on the cellulose ester film treated in the step 1 (third step); Joining the cellulose
2 shows a polarizing plate protective film B (121) coated with a pressure-sensitive adhesive and then laminated on a glass substrate. The polarizing plate according to the present invention was further heated at 60 ° C and 90% RH After leaving for 500 hours in a reliable environment, the degree of polarization of the polarizing plate expressed by the following formula (2) may be in the range of 99.9500% or more.
&Quot; (2) "
Polarization degree (PE) = [(Tp-Tc) / (Tp + Tc)] 1/2 x 100 (%)
Herein, Tp is the transmittance of the polarizing plate in the state where the transmission axes thereof are parallel to each other, and Tc is the transmittance of light of 400 nm to 700 nm in full-wavelength visible light under an environment of 23 DEG C and 55% RH in an orthogonal state.
In the cellulose ester polarizing plate protective film of the present invention, especially when the polarizing plate protective film B contains the plasticizer proposed in the present invention and is within the range of the thickness and degree of substitution of the cellulose ester film, the reliability of the polarizing plate before and after the reliability treatment of the polarizing plate is excellent Able to know.
Hereinafter, the present invention will be described in more detail with reference to examples, but the following examples are for illustrative purposes only and the present invention is not limited thereto.
Example 1
Preparation of Polarizer Protective Film A-Cellulose Ester Film
(1) Preparation of cellulose solution
16 parts by weight of triacetyl cellulose having an average degree of acetyl substitution (DS) of 2.86, 82 parts by weight of a mixed solvent obtained by mixing methylene chloride and methanol in a ratio of 9: 1 (weight ratio), triphenylphosphate (TPP) And 2 parts by weight of a plasticizer mixed with ethyl glycolate (EPEG) at a ratio of 3: 1 (weight ratio) were mixed to prepare a cellulose solution.
(2) Preparation of ultraviolet absorber solution
7.5 parts by weight of a mixed ultraviolet light absorber obtained by mixing Tinuvin 328 (manufactured by Ciba Specialty) and Tinuvin 326 (manufactured by Ciba Specialty) in a ratio of 4: 1 (weight ratio) and 9 parts by weight of methylene chloride and methanol (Weight ratio) were mixed to prepare an ultraviolet absorber solution.
(3) Preparation of Diluted Cellulose Solution Containing Metal Oxide
The cellulose solution of 28.5 parts by weight of silica (SiO 2) 1.5 parts by weight of methylene chloride and methanol 9: Preparation of diluted cellulose solution by mixing 1 (weight ratio) parts of a mixed solvent of 70 parts by weight mixed with comprises silica (metal oxide) Respectively.
(4) Production of film of cellulose
93 parts by weight of the cellulose solution, 4 parts by weight of the dilute cellulose solution containing the metal oxide and 3 parts by weight of the ultraviolet absorber solution were mixed to prepare a casting stock solution. Then, on the surface of the metal belt, a sheet having a thickness of 400 μm and a width of 1800 mm ). While the metal belt was being rotated, the solvent of the casting stock solution was evaporated, stretched and dried to form a cellulose film (TF-40-1) having a thickness of 40 占 퐉. The light transmittance T (380 nm) of the prepared cellulose film at 380 nm wavelength was 2.62%, the light transmittance T (620 nm) at 620 nm was 92.8%, and the b * value was 0.60 in the CIE colorimetric system.
Preparation of Polarizer Protective Film B-Cellulose Ester Film
( 1) Preparation of cellulose solution (initiator solution)
For the cellulose ester, acetyl group of 2.1, butyryl group of 0.2 and total degree of substitution of 2.3 was used, and as a plasticizer, 2 parts by weight of a terminal asymmetric plasticizer having the following chemical formula 2 was used.
(2)
(2) Preparation of Dilute Solution Containing Metal Oxide
20.0 parts by weight of the cellulose solution, 1.5 parts by weight of silica (SiO 2 ), and 78.5 parts by weight of a mixed solvent obtained by mixing methylene chloride and methanol in a weight ratio of 9: 1 were mixed to prepare a dilute cellulose solution containing silica (metal oxide) Respectively.
(3) Production of film of cellulose
100 parts by mass of the main doping liquid and 5 parts by mass of the fine particulate addition liquid were added, sufficiently mixed (Doped A) by an inline mixer, and then uniformly plied to a stainless steel band support of 2000 mm in width using a belt smoothing device. The solvent was evaporated on the stainless steel band support and peeled off from the stainless band support. Then, both ends of the web were held with a tenter and stretched so that the draw ratio in the (TD) direction was 1.3 times in a temperature environment of 170 ° C. After the stretching, the stretching was maintained for a few seconds, the tensile force in the width direction was relaxed, the stretching in the width direction was carried out, the stretching was continued for 35 minutes in the drying section set at 110 DEG C, A cellulose ester film having a thickness of 40 탆 and a polarizing plate protective film B having a knurling width of 10 mm and a height of 8 탆 was prepared.
The cellulose ester film thus obtained was a retardation film having an in-plane retardation value Ro of 40 to 60 nm and a retardation value Rth in the thickness direction of 110 to 140 nm according to the following measurement.
Ro = (nx-ny) xd
Rth = ((nx + ny) / 2-nz) xd
Nx and ny represent refractive indices in the in-plane direction of the film, nz represent refractive indices in the thickness direction of the film, nx > = ny, , And d represents the thickness (nm) of the film. The retardation values Ro and Rth were measured at 590 nm under the environment of 23 ° C and 55% RH using an AxoScan (OPMF-1, Axometrics) optical measuring instrument.
Production of Polarizer
First, a polarizer was produced using the following PVA film.
(1) Polarizer: Production of PVA film
The polyvinyl alcohol film having a thickness of 120 占 퐉 was uniaxially stretched (at a temperature of 110 占 and a stretching magnification of 5 times). This was immersed in an aqueous solution containing 0.075 g of iodine, 5 g of potassium iodide and 100 g of water for 60 seconds and then immersed in an aqueous solution at 68 DEG C containing 6 g of potassium iodide, 7.5 g of boric acid and 100 g of water. This was washed with water and dried to obtain a polarizer (PF-1).
(2) Production of Polarizer
Then, according to the following steps 1 to 5, the polarizer, the cellulose ester film as the polarizing plate protective film B, and the cellulose ester as the polarizing plate protective film A were laminated on the back side as a polarizer protective film To prepare a polarizing plate.
And immersed in a 2 mol / L sodium hydroxide solution at 60 DEG C for 90 seconds, followed by washing with water and drying to obtain a cellulose ester film in which the side bonded to the polarizer was saponified (Step 1).
The polarizing membrane was immersed in a polyvinyl alcohol adhesive tank (bath) having a solid content of 2 mass% for 1 to 3 seconds (Step 2).
In step 2, the excess adhesive adhered to the polarizing film was lightly wiped off and placed on the cellulose ester film treated in step 1 (step 3).
The cellulose ester film laminated in Step 3, the polarizer and the back side cellulose ester film were bonded at a pressure of 20 to 30 N / cm 2 and a conveying speed of about 2 m / min (Step 4).
A sample obtained by bonding the polarizer, the cellulose ester film and the back side cellulose ester film prepared in Step 4 in a dryer at 80 占 폚 was dried for 2 minutes to prepare a polarizing plate (Step 5).
The polarizing plate thus prepared was coated with a pressure-sensitive adhesive on the B-side of the polarizing plate protective film, and laminated on a glass substrate (10 in Fig. 2) having a thickness of 0.5 mm. In this state, the degree of polarization was measured using a spectrophotometer (Jasco, Model V7100) optical measuring instrument under an environment of 23 ° C and 55% RH.
The polarizing plate laminated on the glass substrate 10 was allowed to stand for 500 hours in a reliable environment of 60 DEG C and 90% RH using a high temperature and high humidity chamber, taken out from the high temperature and high humidity chamber again, , And the change in polarization degree before and after the reliability environmental treatment was observed. As shown in the results of Table 4, in the cellulose ester polarizer protective film of the present embodiment, particularly when the polarizer protective film B contains the plasticizer suggested in the present invention and is within the range of the thickness and substitution degree of the cellulose ester film, It was found that the reliability of the polarization degree before and after the treatment was excellent.
Examples 2 to 15
A cellulose ester film A was prepared in the same manner as in Example 1 except that the cellulose ester, the plasticizer, and the dope solution as shown in Tables 1 to 3 were used. Cellulose films (TF-40-1 and TF-60-1) having thicknesses of 40 and 60 mu m were formed by changing the thickness as shown in Table 5 in the same manner as in Example 1. The light transmittance T (380 nm) of the prepared cellulose film at 380 nm wavelength was 2.56%, the light transmittance T (620 nm) at 620 nm was 92.7%, and the b * value was 0.59 in the CIE colorimetric system. In addition, the cellulose ester film B having the film thicknesses of 30, 40 and 50 탆 was prepared after the main dope liquids (B to E) were prepared as shown in Tables 1 to 3, and the properties of the polarizer plate Was measured in the same manner as in Example 1 above.
The polarizers were prepared in the same manner as in Example 1 using the PVA film as shown in Table 4 below, and the reliability of the prepared polarizer was measured. The results are shown in Table 5 below.
* See Table 2, ** See Table 3
Cellulose ester film No.
Comparative Examples 1 to 8
A cellulose ester film A was prepared in the same manner as in Example 1 except that the cellulose ester, the plasticizer and the dope solution as shown in Tables 1 to 4 were used. Cellulose films (TF-40-1 and TF-60-1) having thicknesses of 40 and 60 占 퐉 were prepared in the same manner as in Example 1 except that the thickness was changed as shown in Table 5. The light transmittance T (380 nm) of the prepared cellulose film at 380 nm wavelength was 2.56%, the light transmittance T (620 nm) at 620 nm was 92.7%, and the b * value was 0.59 in the CIE colorimetric system. The cellulose ester film B was prepared in the same manner as in Example 1, except that the main dope liquids (F to I) were prepared as shown in Tables 1 to 4, and then the cellulose ester film B was prepared.
The polarizers were prepared in the same manner as in Example 1 using the PVA film in the same manner as in Table 5, and the reliability of the prepared polarizer was measured. The results are shown in Table 5 above.
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 and scope of the invention as defined in the appended claims. There will be.
10: Die
20: Belt
30: peeling roll
40: Tender (first drying section)
50: Second drying section
60: Winder
10: glass substrate
121: Protective film B
122: Polarizer
123: Protective film A
Claims (10)
As a plasticizer containing a cellulose ester having a total degree of substitution of an acyl group of 2.10 to 2.70 as a plasticizer which also serves as a retarder having a film thickness of 20 to 60 占 퐉 and containing an asymmetric ester compound containing an aromatic group represented by the following formula And a thickness of the protective film B sandwiched by the polarizer is 60 to 160 탆. The cellulose-based polarizing plate of the present invention is excellent in the degree of polarization and reliability.
[Chemical Formula 1]
T + [D + P] n + D
T is a residue of a toluic acid or a benzenecarboxylic acid residue, D is a propyleneglycol having 2 to 8 carbon atoms, neopentylglycol, diethyleneglycol, dipropyleneglycol Triethylene glycol, an alkylene glycol residue having 2 to 12 carbon atoms, an aryl glycol residue having 6 to 12 carbon atoms, or an oxyalkylene glycol residue having 4 to 12 carbon atoms, P is a phthalic acid having 2 to 10 carbon atoms Phthalic acid residue, an alkylene dicarboxylic acid residue having 4 to 12 carbon atoms, or an aryl dicarboxylic acid residue having 6 to 12 carbon atoms, and n represents an integer of 1 or more.
[Equation 1]
Ro = (nx-ny) xd
Rth = {(nx + ny) / 2-nz} xd
Ny is the maximum refractive index in the vertical direction in the film plane and nz is the maximum refractive index in the thickness direction of the film and is 23 DEG C and 55% RH, respectively, where d is the film thickness (nm), nx is the maximum refractive index in the horizontal direction in the film plane, Under the environment of 550 nm.
&Quot; (2) "
Polarization degree (PE) = [(Tp-Tc) / (Tp + Tc)] 1/2 x 100 (%)
Here, Tp is the transmittance of 400 nm to 700 nm of visible light in the wavelength range of visible light at 23 DEG C and 55% RH in a state in which the transmission axes of the polarizing plates are parallel to each other and Tc is orthogonal.
Preparing a cellulose film of polarizing protective film A having a thickness in the range of 20 to 100 mu m by a conventional method;
A cellulose ester having an acyl group with a total substitution degree of 2.10 to 2.70, an asymmetric ester plasticizer containing an aromatic group represented by the following formula (1), a mixed solvent of methylene chloride and methanol, a dilute cellulose solution containing silica as a metal oxide Preparing a cellulose ester film of the polarizing protective film B by evaporating, stretching and drying the solvent;
And bonding the polarizing protective film A and the polarizing protective film B to one surface of the polarizer of the polyvinyl alcohol polarizing film under a constant pressure.
[Chemical Formula 1]
T + [D + P] n + D
T is a residue of a toluic acid or a benzenecarboxylic acid residue, D is a propyleneglycol having 2 to 8 carbon atoms, neopentylglycol, diethyleneglycol, dipropyleneglycol Triethylene glycol, an alkylene glycol residue having 2 to 12 carbon atoms, an aryl glycol residue having 6 to 12 carbon atoms, or an oxyalkylene glycol residue having 4 to 12 carbon atoms, P is a phthalic acid having 2 to 10 carbon atoms Phthalic acid residue, an alkylene dicarboxylic acid residue having 4 to 12 carbon atoms, or an aryl dicarboxylic acid residue having 6 to 12 carbon atoms, and n represents an integer of 1 or more.
[Equation 1]
Ro = (nx-ny) xd
Rth = {(nx + ny) / 2-nz} xd
Ny is the maximum refractive index in the vertical direction in the film plane and nz is the maximum refractive index in the thickness direction of the film and is 23 DEG C and 55% RH, respectively, where d is the film thickness (nm), nx is the maximum refractive index in the horizontal direction in the film plane, Under the environment of 550 nm.
(2)
(3)
[Chemical Formula 4]
[Chemical Formula 5]
[Chemical Formula 6]
(7)
[Chemical Formula 8]
[Chemical Formula 9]
[Chemical formula 10]
(11)
&Quot; (2) "
Polarization degree (PE) = [(Tp-Tc) / (Tp + Tc)] 1/2 x 100 (%)
Here, Tp is the transmittance of 400 nm to 700 nm of visible light in the wavelength range of visible light at 23 DEG C and 55% RH in a state in which the transmission axes of the polarizing plates are parallel to each other and Tc is orthogonal.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPWO2015146599A1 (en) * | 2014-03-25 | 2017-04-13 | コニカミノルタ株式会社 | Retardation film, polarizing plate using the same, and display device |
| KR20190121997A (en) * | 2018-04-19 | 2019-10-29 | 효성화학 주식회사 | Tri-Acetyl Cellulose Film |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5720401B2 (en) | 2011-04-27 | 2015-05-20 | コニカミノルタ株式会社 | Cellulose acetate laminated film, polarizing plate, and liquid crystal display device |
| JP6015469B2 (en) | 2013-01-31 | 2016-10-26 | コニカミノルタ株式会社 | Optical film roll, polarizing plate, and liquid crystal display device |
| WO2014132691A1 (en) | 2013-02-26 | 2014-09-04 | コニカミノルタ株式会社 | Polarizing sheet, polarizing sheet production method and liquid crystal display device |
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2015
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPWO2015146599A1 (en) * | 2014-03-25 | 2017-04-13 | コニカミノルタ株式会社 | Retardation film, polarizing plate using the same, and display device |
| KR20190121997A (en) * | 2018-04-19 | 2019-10-29 | 효성화학 주식회사 | Tri-Acetyl Cellulose Film |
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