Classifications

• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B1/00—Optical elements characterised by the material of which they are made; Optical coatings for optical elements
  • G02B1/10—Optical coatings produced by application to, or surface treatment of, optical elements
  • G02B1/14—Protective coatings, e.g. hard coatings
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B5/00—Optical elements other than lenses
  • G02B5/30—Polarising elements
• • 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
• • 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
• • G—PHYSICS
  • G02—OPTICS
  • G02F—OPTICAL 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
  • G02F1/00—Devices 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
  • G02F1/01—Devices 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 
  • G02F1/13—Devices 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
  • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
  • G02F1/1333—Constructional arrangements; Manufacturing methods
  • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
  • G02F1/133528—Polarisers

Definitions

• the present invention relates to a polarizer protective film, a polarizing plate, and a liquid crystal panel.
• Acrylic resins have excellent transparency, color tone, appearance, heat resistance and processability, and are therefore used, for example, in polarizer protective films (see, for example, Patent Document 1).
• the polarizer protective films are attached to both sides of a polarizer to form polarizing plates, which are then placed on both sides of a liquid crystal cell, thereby being used in liquid crystal panels.
• IPS type LCD panels are preferred for use in LCD televisions and other applications due to their wide viewing angle and excellent color reproducibility.
• the LCD panel may appear slightly yellowish when displayed in black and viewed from an oblique direction.
• variations in the in-plane phase difference of the polarizer protective film may cause unevenness in the display of the LCD panel.
• the objective of the present invention is to provide a polarizer protective film that can achieve both uniformity of in-plane retardation and reduced yellowness when viewed from an oblique direction of the liquid crystal panel.
• a polarizer protective film comprising an acrylic resin composition, the thickness direction retardation Rth at a wavelength of 590 nm being ⁇ 15.0 nm or more and less than 0.0 nm, the acrylic resin composition comprising an acrylic resin having a ring structure in its main chain, the glass transition temperature being 120° C. or more, and the birefringence expression ⁇ nxy being ⁇ 1.0 ⁇ 10 ⁇ 3 or more and ⁇ 1.0 ⁇ 10 ⁇ 4 or less.
• R1 and R2 are each independently a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and R3 is a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, or a cycloalkyl group having 3 to 12 carbon atoms.
• a polarizer protective film according to any one of [1] to [11], in which the absolute value of the Nz coefficient is 0.1 or more and 30.0 or less, the ratio Rth(447)/Rth(548) of the thickness direction retardation Rth(447) at a wavelength of 447 nm to the thickness direction retardation Rth(548) at a wavelength of 548 nm is 0.50 or more and 1.10 or less, and the ratio Rth(628)/Rth(548) of the thickness direction retardation Rth(628) at a wavelength of 628 nm to the thickness direction retardation Rth(548) at a wavelength of 548 nm is 0.50 or more and 2.00 or less.
• the present invention provides a polarizer protection film that can achieve both uniformity of in-plane retardation and reduced yellowness when viewed from an oblique direction of the liquid crystal panel.
• the polarizer protective film of the present embodiment contains an acrylic resin composition.
• the thickness direction retardation Rth of the polarizer protective film of this embodiment at a wavelength of 590 nm is -15.0 nm or more and less than 0.0 nm, preferably -13.0 nm or more and less than -2.5 nm, more preferably -10.0 nm or more and less than -2.5 nm, even more preferably -10.0 nm or more and less than -5.0 nm, and particularly preferably -10.0 nm or more and less than -7.0 nm.
• Rth is -15.0 nm or more and less than 0.0 nm, the yellowness when viewed from an oblique direction of the liquid crystal panel is reduced.
• the polarizer protective film of this embodiment preferably has a yellowness of 50 or less when viewed from an oblique direction of the liquid crystal panel.
• the average value of the in-plane retardation Re of the polarizer protective film of this embodiment is preferably greater than 0.0 nm and equal to or less than 0.7 nm, and more preferably equal to or less than 0.6 nm.
• the average value of Re is equal to or less than 0.7 nm, the uniformity of the in-plane retardation Re is improved.
• the standard deviation of the in-plane retardation Re of the polarizer protective film of this embodiment is less than 0.2.
• nx, ny, and nz are the refractive indices in the X-axis direction, the Y-axis direction, and the Z-axis direction, respectively, when the MD direction is the X-axis, the TD direction is the Y-axis, and the thickness direction of the film is the Z-axis.
• d is the thickness of the film.
• the yellowness of the polarizer protective film of this embodiment is preferably 0.01 or more and 5.00 or less, and more preferably 0.1 or more and 2.0 or less. When the yellowness of the polarizer protective film of this embodiment is 5.00 or less, the polarizer protective film of this embodiment is less colored and has less effect on the color rendering properties of the display.
• the absorbance of the polarizer protective film of this embodiment at a wavelength of 380 nm is preferably 0.01 or more and 1.00 or less, and more preferably 0.10 or more and 0.80 or less.
• the absorbance of the polarizer protective film of this embodiment at a wavelength of 380 nm is 1.00 or less, the polarizer protective film of this embodiment does not substantially contain an ultraviolet absorber.
• the absolute value of the Nz coefficient of the polarizer protective film of this embodiment is preferably 0.1 or more and 30.0 or less.
• the absolute value of the Nz coefficient of the polarizer protective film of this embodiment is 0.1 or more and 30.0 or less, the yellowness is reduced when viewed from an oblique direction of the liquid crystal panel.
• the ratio Rth(447)/Rth(548) of the thickness direction retardation Rth(447) at a wavelength of 447 nm to the thickness direction retardation Rth(548) at a wavelength of 548 nm of the polarizer protective film of this embodiment is preferably 0.50 or more and 1.10 or less, and more preferably 0.80 or more and 1.08 or less.
• Rth(447)/Rth(548) of the polarizer protective film of this embodiment is 0.50 or more and 1.10 or less, the yellowness when viewed from an oblique direction of the liquid crystal panel is reduced.
• the ratio Rth(628)/Rth(548) of the thickness direction retardation Rth(628) at a wavelength of 628 nm to the thickness direction retardation Rth(548) at a wavelength of 548 nm of the polarizer protective film of this embodiment is preferably 0.50 or more and 2.00 or less, and more preferably 0.7 or more and 1.5 or less.
• Rth(628)/Rth(548) of the polarizer protective film of this embodiment is 0.50 or more and 2.00 or less, the yellowness when viewed from an oblique direction of the liquid crystal panel is reduced.
• the photoelastic coefficient of the polarizer protective film of this embodiment is preferably -10 x 10 -12 Pa -1 or more and 10 x 10 -12 Pa -1 or less, more preferably -5.5 x 10 -12 Pa -1 or more and 5.5 x 10 -12 Pa -1 or less, and even more preferably -4.5 x 10 -12 Pa -1 or more and 4.5 x 10 -12 Pa -1 or less.
• the photoelastic coefficient of the polarizer protective film of this embodiment is -10 x 10 -12 Pa -1 or more and 10 x 10 -12 Pa -1 or less, the polarizer protective film of this embodiment is less likely to suffer from color unevenness, and this tendency becomes particularly noticeable under a high temperature and high humidity environment.
• the acrylic resin composition includes an acrylic resin having a ring structure in the main chain.
• the glass transition temperature of the acrylic resin composition is 120°C or higher, preferably more than 120°C, more preferably 121°C or higher, and even more preferably 122°C or higher. If the glass transition temperature of the acrylic resin composition is less than 120°C, orientation relaxation may proceed in a high-temperature and high-humidity environment, and the stability of the retardation may decrease.
• the glass transition temperature of the acrylic resin composition is, for example, 160°C or lower.
• acrylic resin means a polymer of a monomer having an acryloyl group and/or a monomer having a methacryloyl group.
• the acrylic resin may be either a homopolymer or a copolymer.
• the acrylic resin is a copolymer, it may be a copolymer of a monomer not having an acryloyl group or a methacryloyl group.
• the birefringence manifestation ⁇ nxy of the acrylic resin composition is -1.0 ⁇ 10 -3 or more and -0.1 ⁇ 10 -3 or less, preferably -0.8 ⁇ 10 -3 or more and -0.25 ⁇ 10 -3 or less, more preferably -0.8 ⁇ 10 -3 or more and -0.20 ⁇ 10 -3 or less, and even more preferably -0.8 ⁇ 10 -3 or more and -0.12 ⁇ 10 -3 or less.
• ⁇ nxy is -1.0 ⁇ 10 -3 or more, the desired thickness direction retardation is easily manifested when biaxially stretched, and when it is -0.1 ⁇ 10 -3 or less, the in-plane retardation is easily uniform when biaxially stretched.
• the birefringence manifestation ⁇ nxy of an acrylic resin composition refers to the birefringence manifested when a film of the acrylic resin composition in an unstretched state is uniaxially stretched at the free end so that the stretch ratio in the longitudinal direction (lengthwise direction) is 2 times at a temperature 5°C higher than the glass transition temperature of the acrylic resin composition.
• nx and ny are the refractive indices in the X-axis direction and the Y-axis direction, respectively, when the MD direction is the X-axis, the TD direction is the Y-axis, and the thickness direction of the film is the Z-axis.
• Re is the in-plane retardation of the film
• d is the thickness of the film.
• the acrylic resin composition may further contain, for example, polymethyl methacrylate or a methyl methacrylate-styrene copolymer. It is preferable that the acrylic resin contained in the acrylic resin composition does not have structural units derived from aromatic vinyl.
• the content of structural units derived from aromatic vinyl (e.g., styrene) in the acrylic resin composition is preferably 0% by weight or more and 8% by weight or less, more preferably 0.5% by weight or more and 5% by weight or less, even more preferably 0.5% by weight or more and 3% by weight or less, even more preferably 0.5% by weight or more and 2.5% by weight or less, and particularly preferably 1.0% by weight or more and 2.5% by weight or more.
• the content of structural units derived from aromatic vinyl (e.g., styrene) in the acrylic resin composition is 8% by weight or less, the uniformity of the in-plane retardation of the polarizer protective film of this embodiment is improved.
• the acrylic resin composition may further contain additives as long as the purpose of the present invention is not impaired.
• the additives are not particularly limited, but examples include antioxidants, heat stabilizers, light stabilizers, ultraviolet absorbers, specific wavelength absorbing agents or specific wavelength absorbing dyes for cutting blue light, light resistance stabilizers such as radical scavengers, phase difference adjusters, catalysts, plasticizers, lubricants, antistatic agents, colorants, shrinkage prevention agents, antibacterial and deodorizing agents, fluorescent brighteners, and compatibilizers, and two or more of these may be used in combination.
• the 1% weight loss temperature of the acrylic resin composition is preferably 300°C or higher, more preferably 302°C or higher, and even more preferably 305°C or higher.
• the 1% weight loss temperature of the acrylic resin composition is 300°C or higher, contamination of the cooling roll during the production of the raw film is suppressed, and the film formability of the raw film is improved.
• the 1% weight loss temperature of the raw film is, for example, 380°C or lower.
• the weight average molecular weight of the acrylic resin composition is preferably 50,000 or more and 200,000 or less, and more preferably 90,000 or more and 150,000 or less. If the weight average molecular weight of the acrylic resin composition is 50,000 or more, the mechanical properties of the molded product of the acrylic resin composition tend to improve, and if it is 200,000 or less, the moldability of the acrylic resin composition tends to improve.
• the ratio of the weight average molecular weight to the number average molecular weight of the acrylic resin composition is preferably 1.5 or more and 2.5 or less, and more preferably 1.5 or more and 2.2 or less.
• polydispersity of the acrylic resin composition is 1.5 or more, the fluidity of the acrylic resin composition tends to improve and it tends to be easier to mold, and when it is 2.5 or less, the mechanical properties such as impact resistance, toughness, and bending resistance of the molded product of the acrylic resin composition tend to improve.
• the number average molecular weight and weight average molecular weight of the acrylic resin composition are values calculated using standard polystyrene as measured by gel permeation chromatography (GPC).
• the number average molecular weight and weight average molecular weight of the acrylic resin composition can be controlled by the type and amount of polymerization initiator and chain transfer agent used when synthesizing the acrylic resin.
• the polarizer protective film of this embodiment can be attached to a polarizer to form a polarizing plate.
• the polarizer is not particularly limited, and any known polarizer can be used.
• the polarizing plate can also be combined with a liquid crystal cell to form a liquid crystal panel. In this case, it is preferable to use an IPS-type liquid crystal cell with a wide viewing angle.
• the polarizer protective film of this embodiment when it is disposed on the side opposite the liquid crystal cell, it may not contain an ultraviolet absorbing agent, or may not substantially contain an ultraviolet absorbing agent.
• the acrylic resin having a ring structure in the main chain (hereinafter referred to as acrylic resin) preferably has a structural unit containing, in the main chain, one or more ring structures selected from the group consisting of a glutarimide ring, a lactone ring, a maleic anhydride ring, a maleimide ring, and a glutaric anhydride ring.
• the structural unit containing a glutarimide ring in the main chain is represented, for example, by the following formula (1).
• R1 and R2 are each independently a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and R3 is a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, or a cycloalkyl group having 3 to 12 carbon atoms.
• the acrylic resin having the structural unit represented by formula (1) can be produced using a known method.
• An example of a method for producing an acrylic resin having the structural unit represented by formula (1) is described below.
• a twin-screw extruder equipped with a die at the outlet is used to melt the methyl methacrylate resin, which is then imidized and extruded from the die into strands.
• the strands are cooled using a water bath and then pelletized using a pelletizer to obtain imidized methyl methacrylate resin.
• a twin-screw extruder equipped with a die at the outlet is used to melt the imidized methyl methacrylate resin, which is then esterified and extruded from the die into strands.
• the strands are cooled using a water bath and then pelletized using a pelletizer to obtain an acrylic resin having a structural unit represented by formula (1).
• imidizing agent examples include ammonia and primary amines represented by the following formula (2). Among these, monomethylamine is preferred.
• esterifying agents include dimethyl carbonate, 2,2-dimethoxypropane, dimethyl sulfoxide, triethyl orthoformate, trimethyl orthoacetate, trimethyl orthoformate, diphenyl carbonate, dimethyl sulfate, methyl toluene sulfonate, methyl trifluoromethyl sulfonate, methyl acetate, methanol, ethanol, methyl isocyanate, p-chlorophenyl isocyanate, dimethylcarbodiimide, dimethyl-t-butylsilyl chloride, isopropenyl acetate, dimethylurea, tetramethylammonium hydroxide, dimethyldiethoxysilane, tetra-n-butoxysilane, dimethyl(trimethylsilane) phosphite, trimethyl phosphite, trimethyl phosphate, tricresyl phosphate, diazomethane, ethylene oxide, propylene oxide,
• the content of structural units containing a ring structure in the main chain in the acrylic resin is preferably 1% by weight or more and 80% by weight or less.
• the glass transition temperature of the acrylic resin is preferably 120°C or more and 160°C or less.
• the acrylic resin may further contain structural units derived from a (meth)acrylic acid ester.
• Examples of (meth)acrylic acid esters include alkyl (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl (meth)acrylate, and isobutyl (meth)acrylate; aryl (meth)acrylates such as phenyl (meth)acrylate; aralkyl (meth)acrylates such as benzyl (meth)acrylate; and cycloalkyl (meth)acrylates such as cyclohexyl (meth)acrylate, and two or more of these may be used in combination.
• alkyl methacrylates are preferred, and methyl methacrylate is particularly preferred.
• the content of structural units derived from alkyl methacrylate in the acrylic resin is preferably 50% by weight or more, more preferably 75% by weight or more, and particularly preferably 90% by weight or more.
• the content of structural units derived from acrylic acid esters in the acrylic resin is preferably less than 1% by weight, more preferably less than 0.5% by weight, and particularly preferably less than 0.3% by weight.
• the acrylic resin may further have structural units derived from other monomers.
• other monomers include, but are not limited to, aromatic monomers such as styrene and methylstyrene; and nitrile monomers such as acrylonitrile and methacrylonitrile.
• the polarizer protective film of the present embodiment can be produced by a known method. An example of a method for producing the polarizer protective film of the present embodiment will be described below.
• an extruder equipped with a die at the outlet is used to knead the acrylic resin together with a methyl methacrylate-styrene copolymer, if necessary, and then a strand is extruded from the die.
• the strand is cooled using a water tank, and then the strand is pelletized using a pelletizer to obtain an acrylic resin composition.
• an extruder equipped with a T-die at the outlet is used to melt the acrylic resin composition, and then a sheet is extruded from the T-die and cooled with a cooling roll to obtain a raw film.
• the raw film is biaxially stretched to obtain the polarizer protective film of this embodiment.
• the biaxial stretching may be simultaneous biaxial stretching or sequential biaxial stretching.
• the temperature when the raw film is biaxially stretched is preferably (Tg+5)°C or more and (Tg+20)°C or less, more preferably (Tg+6)°C or more and (Tg+18)°C or less, and even more preferably (Tg+7)°C or more and (Tg+15)°C or less, where Tg is the glass transition temperature of the acrylic resin composition.
• the areal ratio when the raw film is biaxially stretched is not particularly limited, but is, for example, 2 times or more and 10 times or less.
• the stretching speed when the raw film is biaxially stretched is not particularly limited, but is, for example, 1.1 times/min or more and 100 times/min or less.
• the first stage stretching speed and the second stage stretching speed may be the same or different.
• the first stage stretching is usually in the longitudinal direction (MD direction)
• the second stage stretching is in the transverse direction (TD direction).
• the 1 H-NMR spectrum of the acrylic resin was measured using a nuclear magnetic resonance apparatus AvanceIII (manufactured by BRUKER) with a proton resonance frequency of 400 MHz.
• the molar ratio of the structural unit derived from methyl methacrylate and the structural unit containing a glutarimide ring in the main chain was converted into weight, and the content of the structural unit containing a glutarimide ring in the main chain was calculated.
• the molar ratio was calculated from the peak area A derived from the O-CH 3 proton of methyl methacrylate around 3.5 to 3.8 ppm and the peak area B derived from the N-CH 3 proton of glutarimide around 3.0 to 3.3 ppm.
• Glass Transition Temperature Using a high-sensitivity differential scanning calorimeter DSC7000X (manufactured by Hitachi High-Tech Science), 10 mg of the acrylic resin or acrylic resin composition was heated at a heating rate of 10° C./min in a nitrogen atmosphere, and the glass transition temperature was determined by the midpoint method.
• thermogravimetric and differential thermal analyzer STA7200 manufactured by Hitachi High-Tech Science
• 10 mg of the acrylic resin composition was heated from room temperature at a heating rate of 10° C./min in a nitrogen atmosphere to determine the 1% weight loss temperature.
• the thickness direction retardation Rth of the polarizer protective film at a wavelength of 590 nm was measured using a retardation measuring device KOBRA-WR (manufactured by Oji Scientific Instruments).
• the polarizer protective film was cut into a 3 cm square, and the yellowness index (YI) was measured using a color meter SC-P (manufactured by Suga Test Instruments Co., Ltd.) in accordance with JIS K7373:2006.
• the absorbance of the polarizer protective film at a wavelength of 380 nm was measured using an ultraviolet-visible-near infrared spectrophotometer UV-560 (manufactured by JASCO Corporation).
• the photoelastic coefficient of the polarizer protective film was measured using a phase difference measuring device KOBRA (manufactured by Oji Scientific Instruments). Specifically, the polarizer protective film was cut into a size of 15 mm x 60 mm, and the change in phase difference was measured when a tensile load was applied to the film by changing the load from 0 g to 1100 g in increments of 100 g. The stress calculated from the tensile load value was plotted on the X-axis, and the birefringence calculated from the measured value of the phase difference and the thickness of the film was plotted on the Y-axis. The slope of the straight line of the plotted graph was calculated to be the photoelastic coefficient.
• a liquid crystal panel simulation was performed using a liquid crystal simulator LCD Master (manufactured by Shintech). At this time, a polarizing plate arranged on the light source side, an IPS type liquid crystal cell with an in-plane retardation Re of 295 nm, and a polarizing plate arranged on the viewing side were arranged in this order, and the measurement results of the thickness direction retardation Rth were input as the optical characteristics of the polarizer protective film on the side facing the liquid crystal cell of the polarizing plate arranged on the light source side and the viewing side.
• the in-plane retardation Re ( ⁇ ) at each wavelength and the retardation R40 ( ⁇ ) measured by tilting the absorption axis by 40° as the tilt axis were measured, and then the three-dimensional refractive index calculation software N-Calc (manufactured by Oji Scientific Instruments) was used to calculate the three-dimensional refractive indexes nx ( ⁇ ), ny ( ⁇ ), and nz ( ⁇ ) at each wavelength.
• Nz coefficient [Rth(548)/Re(548)]+0.5
• the Nz coefficient was calculated by:
• Weight average molecular weight, number average molecular weight and polydispersity index The weight average molecular weight (Mw), number average molecular weight (Mn) and polydispersity (Mw/Mn) of the acrylic resin composition were calculated by gel permeation chromatography (GPC) under the following conditions using a sample solution prepared by dissolving 20 mg of the acrylic resin composition in 10 mL of tetrahydrofuran.
• Measuring equipment HLC-8420GPC (manufactured by Tosoh)
• Detector RI detector
• Eluent tetrahydrofuran Guard column: TSKgel guard column Super H-L (manufactured by Tosoh)
• Analytical columns TSKgel Super H5000, Super H4000, Super H3000, Super H2000 (manufactured by Tosoh) (in series)
• Eluent flow rate 0.6 mL/min Measurement temperature: 40°C Standard material: Standard polystyrene (Tosoh)
• Acrylic resin 2 was obtained in the same manner as acrylic resin 1.
• Acrylic resin 2 had a glass transition temperature of 125° C. and a content of structural units containing glutarimide rings in the main chain of 15% by weight.
• Acrylic resin 3 was obtained in the same manner as acrylic resin 1, except that methyl methacrylate-styrene copolymer TX-100 (manufactured by Denka) having a styrene-derived structural unit content of 40% by weight was used instead of the methyl methacrylate resin, and the amount of monomethylamine added was 8.2% by weight relative to the methyl methacrylate-styrene copolymer.
• Acrylic resin 5 had a glass transition temperature of 125° C. and a content of structural units containing a glutarimide ring in the main chain of 45% by weight.
• Table 1 shows the properties of acrylic resin.
• the acrylic resin composition had a glass transition temperature of 123°C, a 1% weight loss temperature of 308°C, an Mw of 81,000, and an Mw/Mn of 1.62.
• the sheet extruded from the T-die was cooled using a cooling roll to obtain a raw film with a width of 160 mm and a thickness of 160 ⁇ m.
• the raw film was simultaneously biaxially stretched at a temperature 15°C higher than the glass transition temperature of the acrylic resin composition so that the stretch ratio was 2 times in both the longitudinal and transverse directions, resulting in a polarizer protection film measuring 280 mm x 280 mm.
• Example 2 A polarizer protective film was obtained in the same manner as in Example 1, except that the mixing ratios of acrylic resin 1 and KT-89 (manufactured by Denka) were changed to 90% by weight and 10% by weight, respectively. At this time, the acrylic resin composition had a glass transition temperature of 123° C., a 1% weight loss temperature of 308° C., an Mw of 81,000, and an Mw/Mn of 1.62.
• Example 3 A polarizer protective film was obtained in the same manner as in Example 2, except that the raw film was simultaneously biaxially stretched at a temperature 7° C. higher than the glass transition temperature of the acrylic resin composition.
• Example 4 A polarizer protective film was obtained in the same manner as in Example 2, except that a methyl methacrylate-styrene copolymer MS-750 (manufactured by Toyo Styrene) having a styrene-derived structural unit content of 25% by weight was used instead of KT-89 (manufactured by Denka), and the original film was simultaneously biaxially stretched at a temperature 10° C. higher than the glass transition temperature of the acrylic resin composition. At this time, the acrylic resin composition had a glass transition temperature of 122° C., a 1% weight loss temperature of 306° C., an Mw of 76,000, and an Mw/Mn of 1.59.
• Example 5 A polarizer protective film was obtained in the same manner as in Example 4, except that 10% by weight of methyl methacrylate resin Parapet HM (manufactured by Kuraray) was added instead of KT-89 (manufactured by Denka). At this time, the acrylic resin composition had a glass transition temperature of 120° C., a 1% weight loss temperature of 302° C., an Mw of 81,000, and an Mw/Mn of 1.59.
• methyl methacrylate resin Parapet HM manufactured by Kuraray
• KT-89 manufactured by Denka
• Example 1 Comparative Example 1 Except for not using KT-89 (manufactured by Denka), a polarizer protective film was obtained in the same manner as in Example 1. At this time, the acrylic resin composition had a glass transition temperature of 123°C and a 1% weight loss temperature of 310°C.
• Comparative Example 2 A polarizer protective film was obtained in the same manner as in Comparative Example 1, except that acrylic resin 2 was used instead of acrylic resin 1. In this case, the acrylic resin composition had a glass transition temperature of 125° C. and a 1% weight loss temperature of 315° C.
• Example 3 A polarizer protective film was obtained in the same manner as in Example 1, except that the acrylic resin 1 was not used and the original film was simultaneously biaxially stretched at a temperature 20° C. higher than the glass transition temperature of the acrylic resin composition. At this time, the acrylic resin composition had a glass transition temperature of 117° C. and a 1% weight loss temperature of 297° C.
• Comparative Example 4 A polarizer protective film was obtained in the same manner as in Comparative Example 3, except that a methyl methacrylate-styrene copolymer MS800 (manufactured by Nippon Steel Chemical Co., Ltd.) having a styrene-derived structural unit content of 20% by weight was used instead of KT-89 (manufactured by Denka Co., Ltd.) and the raw film was simultaneously biaxially stretched at a temperature 30° C. higher than the glass transition temperature of the acrylic resin composition. At this time, the acrylic resin composition had a glass transition temperature of 115° C. and a 1% weight loss temperature of 296° C.
• MS800 manufactured by Nippon Steel Chemical Co., Ltd.
• KT-89 manufactured by Denka Co., Ltd.
• Comparative Example 5 A polarizer protective film was obtained in the same manner as in Comparative Example 1, except that acrylic resin 3 was used instead of acrylic resin 1, and the original film was simultaneously biaxially stretched at a temperature 35° C. higher than the glass transition temperature of the acrylic resin composition. At this time, the acrylic resin composition had a glass transition temperature of 125° C. and a 1% weight loss temperature of 320° C.
• Table 2 shows the properties and evaluation results of the acrylic resin composition and the polarizer protective film.
• the polarizer protective films of Examples 1 to 5 achieve both a reduction in the standard deviation of Re and a reduction in YI when viewed from an oblique direction of the liquid crystal panel.
• the polarizer protective film of Comparative Example 1 has a ⁇ nxy of 0.0 and an Rth of 0.0 nm, so that the YI is large when viewed from an oblique direction of the liquid crystal panel.
• the polarizer protective film of Comparative Example 2 has a ⁇ nxy of 4.0 ⁇ 10 ⁇ 4 and an Rth of 10.2 nm, so that the YI is large when viewed from an oblique direction of the liquid crystal panel.
• the polarizer protective films of Comparative Examples 3 to 5 have a ⁇ nxy of ⁇ 1.3 ⁇ 10 ⁇ 3 , ⁇ 2.5 ⁇ 10 ⁇ 3 , and ⁇ 3.3 ⁇ 10 ⁇ 3 , respectively, so that the standard deviation of Re is large.

Landscapes

• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Nonlinear Science (AREA)
• Mathematical Physics (AREA)
• Chemical & Material Sciences (AREA)
• Crystallography & Structural Chemistry (AREA)
• Polarising Elements (AREA)
• Manufacture Of Macromolecular Shaped Articles (AREA)

Priority Applications (3)

Applications Claiming Priority (2)

Related Child Applications (1)

Publications (1)

Family

ID=92905536

Family Applications (1)

Country Status (4)

Citations (4)

• 2024
  • 2024-03-27 CN CN202480023918.XA patent/CN120981745A/zh active Pending
  • 2024-03-27 WO PCT/JP2024/012147 patent/WO2024204295A1/ja not_active Ceased
  • 2024-03-27 JP JP2025510996A patent/JPWO2024204295A1/ja active Pending
• 2025
  • 2025-09-26 US US19/342,433 patent/US20260029674A1/en active Pending

Patent Citations (4)

Also Published As

Similar Documents

Legal Events