WO2021251355A1 - Plaque de protection d'affichage à cristaux liquides, plaque de protection d'affichage à cristaux liquides à surface incurvée, et leurs procédés de fabrication - Google Patents

Plaque de protection d'affichage à cristaux liquides, plaque de protection d'affichage à cristaux liquides à surface incurvée, et leurs procédés de fabrication Download PDF

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Publication number
WO2021251355A1
WO2021251355A1 PCT/JP2021/021659 JP2021021659W WO2021251355A1 WO 2021251355 A1 WO2021251355 A1 WO 2021251355A1 JP 2021021659 W JP2021021659 W JP 2021021659W WO 2021251355 A1 WO2021251355 A1 WO 2021251355A1
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liquid crystal
crystal display
resin
protective plate
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PCT/JP2021/021659
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English (en)
Japanese (ja)
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侑史 大澤
正晴 山野
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株式会社クラレ
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Priority to JP2022530562A priority Critical patent/JPWO2021251355A1/ja
Publication of WO2021251355A1 publication Critical patent/WO2021251355A1/fr

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/30—Layered products comprising a layer of synthetic resin comprising vinyl (co)polymers; comprising acrylic (co)polymers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
    • B32B7/02—Physical, chemical or physicochemical properties
    • B32B7/023—Optical properties
    • 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
    • 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
    • G02F1/13363—Birefringent elements, e.g. for optical compensation

Definitions

  • the present invention relates to a liquid crystal display protective plate, a liquid crystal display protective plate with a curved surface, and a method for manufacturing these.
  • a protective plate may be provided on the front side thereof in order to prevent scratches on the surface.
  • this protective plate is referred to as a "liquid crystal display protective plate”.
  • the liquid crystal display protective plate includes a resin plate composed of at least one thermoplastic resin layer and, if necessary, a cured film formed on at least one surface of the resin plate.
  • Patent Document 1 discloses a scratch-resistant resin plate that includes a methacrylic resin plate and a cured film formed on at least one of the surfaces thereof and is suitable as a display window protection plate for a portable information terminal (scratch-resistant resin plate). Claims 1, 2, 7, paragraph 0010, etc.).
  • Patent Document 2 describes a polycarbonate system for a liquid crystal display cover including a laminated board in which a methacrylic resin layer is laminated on one surface of a polycarbonate resin layer and a cured film formed on the methacrylic resin layer of the laminated board. A resin laminate is disclosed (claim 1, paragraph 0008, etc.).
  • the liquid crystal display protection plate is installed on the front side (viewer side) of the liquid crystal display, and the viewer sees the screen of the liquid crystal display through this protection plate.
  • the liquid crystal display protective plate hardly changes the polarization property of the light emitted from the liquid crystal display, when the screen is viewed through a polarizing filter such as polarized sunglasses, the angle formed by the polarization axis of the emitted light and the transmission axis of the polarizing filter. In some cases, the screen becomes dark and the visibility of the image is reduced (blackout phenomenon).
  • Patent Document 3 comprises a scratch-resistant resin plate having a cured film formed on at least one surface of the resin plate, and has an in-plane retardation value (also referred to as “Re value”) of 85 to 300 nm.
  • a liquid crystal display protective plate is disclosed (claim 1).
  • a liquid crystal display protective plate with a curved surface matching the shape is used for a display having a curved surface.
  • a cured film is formed on a flat resin plate obtained by extrusion molding, if necessary, and then thermoforming such as press molding, vacuum forming, and pressure molding is performed to obtain a curved liquid crystal display protective plate.
  • the resin plate included in the liquid crystal display protective plate has a Re value within a preferable range both before and after thermoforming, and the variation in the Re value is small.
  • Patent Document 4 It is an object of Patent Document 4 to provide a resin laminate (resin plate) which is excellent in thermoformability or printability at a low temperature and suppresses coloring and color unevenness after thermoforming.
  • an acrylic resin layer is laminated on at least one surface of a polycarbonate resin layer by coextrusion molding, and the heat shrinkage rate in the width direction is -10 to 0%, and the heat shrinkage rate in the extrusion direction is A resin laminate having a Re value of 0 to 10% and a Re value of 1500 nm or less is disclosed (claim 1).
  • the polycarbonate-based resin has a terminal structure derived from a specific monovalent phenol, so that the glass transition temperature of the polycarbonate-based resin is lowered and thermoformability at a low temperature is possible (paragraph 0018). ..
  • the resin laminate described in Patent Document 4 preferably has a hard coat layer on the acrylic resin layer (claim 7).
  • the resin plate is preferably a laminated plate in which a methacrylic resin layer is laminated on at least one surface of a polycarbonate-based resin layer (claim 6 of Patent Document 3, paragraph 0090 of Patent Document 4). ).
  • the birefringence of the polycarbonate-based resin layer can be adjusted by adjusting the molding conditions according to the thickness of the resin plate, and the Re value of the liquid crystal display protective plate can be adjusted within a suitable range. Yes (paragraph 0036 of Patent Document 3, etc.).
  • FIG. 7 shows an image diagram showing the relationship between stress and birefringence, and the relationship between orientation birefringence, stress birefringence, and photoelastic coefficient.
  • the polycarbonate-based resin used in Patent Documents 3 and 4 has a very large absolute value of photoelastic coefficient of 90 ⁇ 10-12 / Pa, and the Re value changes with a slight stress. Therefore, when a polycarbonate resin is used, it is difficult to obtain an optically uniform liquid crystal display protective plate. For example, when observing the liquid crystal display protective plate on the liquid crystal screen through a polarizing filter, color unevenness may be observed due to the variation in the Re value. In particular, after thermoforming, the variation in the Re value of the resin plate tends to increase due to the residual stress generated in the cooling process of thermoforming.
  • the methacrylic resin used in Patent Document 1 has a small absolute value of photoelastic coefficient of 3.2 ⁇ 10-12 / Pa, and the Re value does not easily change due to stress. Therefore, when a methacrylic resin is used, an optically uniform liquid crystal display protective plate can be obtained.
  • the absolute value of the orientation birefringence of the methacrylic resin is as small as 4.0 ⁇ 10 -4 , the Re value of the obtained liquid crystal display protective plate tends to be as small as about 20 nm, although it depends on the thickness.
  • the Re value of the liquid crystal display protection plate when the Re value of the liquid crystal display protection plate is larger than a suitable range, the difference in light transmittance of each wavelength in the visible light region becomes large when visually recognized through a polarizing filter, and various colors can be seen. Visibility may be reduced (colored phenomenon).
  • the present invention has been made in view of the above circumstances, and the in-plane retardation value (Re value) is within a suitable range both before and after thermoforming, the variation is small, and the variation is small, and the liquid crystal display is passed through. It is an object of the present invention to provide a liquid crystal display protective plate capable of suppressing deterioration of visibility such as color unevenness, blackout, and coloring when observing a liquid crystal display protective plate on a liquid crystal screen.
  • the present invention provides the following [1] to [14], a liquid crystal display protective plate, a curved liquid crystal display protective plate, and a method for manufacturing these.
  • a flat resin plate having a phase difference adjusting layer laminated on at least one surface of the base material layer is included.
  • the phase difference adjusting layer is the absolute value of photoelastic coefficient (C A) is 10.0 ⁇ 10 -12 / Pa or less, and the width 20 mm, length 40 mm, a test piece having a thickness of 1 mm, the glass transition temperature Absolute value of orientation birefringence ( ⁇ n A ) obtained by uniaxially stretching at a rate of 3 mm / min at a higher temperature of 10 ° C.
  • the test piece Contains the transparent thermoplastic resin (A) of 10.0 ⁇ 10 -4 to 100.0 ⁇ 10 -4.
  • the base layer is the absolute value of photoelastic coefficient (C B) is 10.0 ⁇ 10 -12 / Pa or less, and the width 20 mm, length 40 mm, a test piece having a thickness of 1 mm, than the glass transition temperature
  • C B photoelastic coefficient
  • the absolute value of the orientation birefringence ( ⁇ n B ) obtained by uniaxially stretching at a rate of 3 mm / min at a high temperature of 10 ° C.
  • the flat resin plate is the liquid crystal display protective plate according to [1], wherein the standard deviation of the in-plane retardation value within the range of 17 cm in width and 22 cm in length is 15.0 nm or less.
  • the flat resin plate is heated to a temperature of Tg B or more and Tg A or less, the absolute value of the rate of change of the in-plane retardation value after heating with respect to before heating is 50% or less [1]. Or the liquid crystal display protective plate of [2].
  • the standard deviation of the in-plane retardation value within the range of width 17 cm and length 22 cm is 25.0 nm or less [1].
  • the transparent thermoplastic resin (A) contains an aromatic vinyl monomer unit and contains.
  • the content of the aromatic vinyl monomer unit in the transparent thermoplastic resin (A) is V [mass%]
  • Display protection plate. 6.0 ⁇ V ⁇ T A ⁇ 30.0 ⁇ (1)
  • the liquid crystal display protective plate of [6] wherein the cured film is a cured product of a thermosetting material.
  • a resin plate having a curved surface in which a phase difference adjusting layer is laminated on at least one surface of a base material layer is included.
  • the phase difference adjusting layer is the absolute value of photoelastic coefficient (C A) is 10.0 ⁇ 10 -12 / Pa or less, and the width 20 mm, length 40 mm, a test piece having a thickness of 1 mm, the glass transition temperature Absolute value of orientation birefringence ( ⁇ n A ) obtained by uniaxially stretching at a rate of 3 mm / min at a higher temperature of 10 ° C. and measuring the in-plane retardation value of the central portion of the test piece.
  • ⁇ n A glass transition temperature Absolute value of orientation birefringence
  • the base layer is the absolute value of photoelastic coefficient (C B) is 10.0 ⁇ 10 -12 / Pa or less, and the width 20 mm, length 40 mm, a test piece having a thickness of 1 mm, than the glass transition temperature
  • C B photoelastic coefficient
  • the absolute value of the orientation birefringence ( ⁇ n B ) obtained by uniaxially stretching at a rate of 3 mm / min at a high temperature of 10 ° C. and measuring the in-plane retardation value of the central portion of the test piece is Containing transparent thermoplastic resin (B) less than 10.0 ⁇ 10 -4,
  • Tg A > Tg B.
  • the thickness of the base layer was T B, a T A ⁇ T B, A liquid crystal display protective plate with a curved surface, wherein the in-plane retardation value of the resin plate having a curved surface is 50 to 330 nm.
  • the resin plate having a curved surface is the liquid crystal display protective plate with a curved surface according to [8], wherein the standard deviation of the in-plane retardation value within the range of 17 cm in width and 22 cm in length is 25.0 nm or less.
  • the curved liquid crystal display protective plate according to [8] or [9] which has a cured film on at least one of the outermost surfaces.
  • the curved liquid crystal display protective plate according to [10] wherein the cured film is a cured product of a thermosetting material.
  • [12] A step of forming the flat resin plate in which the phase difference adjusting layer is laminated on at least one surface of the base material layer.
  • a step of forming a flat resin plate in which the phase difference adjusting layer is laminated on at least one surface of the base material layer is a step of forming a flat resin plate in which the phase difference adjusting layer is laminated on at least one surface of the base material layer.
  • the method for manufacturing a liquid crystal display protective plate with a curved surface according to [8] or [9], which comprises a step of heating the flat resin plate to a temperature of Tg B or more and Tg A or less and thermoforming into a shape having a curved surface.
  • the in-plane retardation value (Re value) is within a suitable range both before and after thermoforming, the variation is small, and the liquid crystal display on the liquid crystal screen is protected through a polarizing filter. It is possible to provide a liquid crystal display protective plate capable of suppressing deterioration of visibility such as color unevenness, blackout, and coloring when observing the plate.
  • the terms "film”, “sheet”, or “plate” are used, depending on the thickness, but there is no clear distinction between them.
  • the "resin plate” referred to in the present specification shall include a “resin film” and a “resin sheet”.
  • the glass transition temperature of a general material is represented by "Tg”.
  • the present invention relates to a liquid crystal display protective plate.
  • the liquid crystal display protective plate can be suitably used for protecting a liquid crystal display and a touch panel display in which a liquid crystal display and a touch panel are combined.
  • the liquid crystal display protective plate of the present invention includes a flat resin plate in which a phase difference adjusting layer is laminated on at least one surface of a base material layer.
  • the flat resin plate is preferably an extruded plate.
  • the liquid crystal display protective plate of the present invention described above can be thermally molded to manufacture a liquid crystal display protective plate with a curved surface.
  • the liquid crystal display protective plate with a curved surface of the present invention includes a resin plate having a curved surface in which a phase difference adjusting layer is laminated on at least one surface of a base material layer.
  • the resin plate having a curved surface is a thermoformed plate obtained by thermoforming a flat resin plate.
  • the liquid crystal display protective plate and the liquid crystal display protective plate with a curved surface of the present invention can have a cured film on at least one of the outermost surfaces, if necessary.
  • the liquid crystal display protective plate having a cured film is also referred to as a "cured film-containing liquid crystal display protective plate".
  • the phase difference adjusting layer contains a transparent thermoplastic resin (A) having specific optical characteristics, and the base material layer is transparent having specific optical characteristics.
  • Tg A glass transition temperature of the phase difference adjusting layer
  • Tg B glass transition temperature of the substrate layer
  • the in-plane retardation value (also referred to as “Re value”) of the flat resin plate and the resin plate having a curved surface is 50 to 330 nm.
  • the standard deviation of the Re value within the range of 17 cm in width and 22 cm in length is preferably 25.0 nm or less, more preferably 15.0 nm or less.
  • the absolute value of the rate of change of the Re value after heating with respect to that before heating is preferably 50% or less.
  • the standard deviation of the Re value within the range of 17 cm in width and 22 cm in length is preferably 25.0 nm or less.
  • the resin plate having a curved surface preferably has a standard deviation of the Re value within a range of 17 cm in width and 22 cm in length of 25.0 nm or less.
  • FIG. 1 and 2 are schematic cross-sectional views of the liquid crystal display protective plate of the first and second embodiments according to the present invention.
  • FIG. 3 is a schematic cross-sectional view of a liquid crystal display protective plate containing a cured film according to an embodiment of the present invention.
  • reference numerals 1 and 2 are liquid crystal display protective plates
  • reference numeral 3 is a cured film-containing liquid crystal display protective plate
  • reference numerals 16A and 16B are flat resin plates
  • reference numeral 21 is a retardation adjustment layer
  • reference numeral 22 is a substrate layer
  • reference numeral 31 Indicates a cured film, respectively.
  • the liquid crystal display protective plate 1 of the first embodiment is composed of a flat resin plate 16A having a two-layer structure in which a retardation adjusting layer 21 is laminated on one side of a base material layer 22.
  • the liquid crystal display protective plate 2 of the second embodiment is composed of a flat resin plate 16B having a three-layer structure in which the phase difference adjusting layer 21 is laminated on both surfaces of the base material layer 22.
  • the cured film-containing liquid crystal display protective plate 3 has a cured film 31 formed on at least one surface of a flat resin plate 16B having a three-layer structure in which retardation adjusting layers 21 are laminated on both sides of a base material layer 22. .. In the example shown in FIG.
  • the cured film 31 is formed on both surfaces of the flat resin plate 16B.
  • the configuration of the liquid crystal display protective plate is not limited to the illustrated example, and the design can be appropriately changed as long as the gist of the present invention is not deviated.
  • a flat liquid crystal display protective plate as shown in FIGS. 1 to 3 can be thermoformed to manufacture a curved liquid crystal display protective plate.
  • the test piece was uniaxially stretched at a rate of 3 mm / min at a temperature 10 ° C. higher than the glass transition temperature at a stretching rate of 100%, and the in-plane retardation value of the central portion of the test piece after uniaxial stretching was measured and obtained.
  • It contains a transparent thermoplastic resin (A) having an absolute value of the orientation birefringence ( ⁇ n A ) of 10.0 ⁇ 10 -4 to 100.0 ⁇ 10 -4.
  • Ritalization is the phase difference between the light in the direction of the molecular backbone and the light in the direction perpendicular to it.
  • a polymer can be obtained by heating and melting to obtain an arbitrary shape, but it is known that retardation occurs due to stress generated in the process of heating and cooling and orientation of molecules.
  • retardation means in-plane retardation unless otherwise specified.
  • the Re value of the resin plate is represented by the following formula (i).
  • [Re value of resin plate] [birefringence ( ⁇ N)] ⁇ [thickness (d)] ...
  • Birefringence ( ⁇ N) is expressed by the following equation (ii).
  • [Birerefringence] [Stress birefringence] + [Orientation birefringence] ...
  • the stress birefringence and the orientation birefringence are represented by the following equations (iii) and (iv), respectively.
  • [Stress birefringence] [photoelastic coefficient (C)] ⁇ [stress] ...
  • FIG. 7 shows an image diagram showing the relationship between stress and birefringence, and the relationship between orientation birefringence, stress birefringence, and photoelastic coefficient.
  • the optical properties of the transparent thermoplastic resin (A) and the transparent thermoplastic resin (B) are specified by the photoelastic coefficient and orientation birefringence shown in FIG. 7 as a model.
  • the liquid crystal display protective plate and the liquid crystal display protective plate with a curved surface of the present invention include a phase difference adjusting layer containing the transparent thermoplastic resin (A) having the above-mentioned specific optical characteristics, so that the liquid crystal on the liquid crystal screen is passed through a polarizing filter. It is possible to suppress deterioration of visibility such as color unevenness and blackout when observing the display protective plate.
  • the "Re value of the resin plate” is an average value of the Re values of about 110,000 birefringent pixels within the measurement range of 17 cm in width and 22 cm in length, unless otherwise specified.
  • the "standard deviation of the Re value of the resin plate” is the standard deviation of the Re value of about 110,000 birefringent pixels within the measurement range of 17 cm in width and 22 cm in length.
  • the average value and standard deviation of the Re value can be measured, for example, by using a retardation measuring device "WPA-100-L” manufactured by Photonic Lattice Co., Ltd. and by the method described in the section [Example] below.
  • the Re value of the flat resin plate and the resin plate having a curved surface is 50 to 330 nm, preferably 70 to 250 nm, more preferably 80 to 200 nm, and particularly preferably 90 to 150 nm. If the Re value is less than the above lower limit, blackout may occur when observing the liquid crystal display protection plate on the liquid crystal screen through the polarizing filter, regardless of the relationship between the polarizing axis of the emitted light and the transmission axis of the polarizing filter. There is. When the Re value exceeds the above upper limit value, when visually recognized through a polarizing filter, the difference in light transmittance of each wavelength in the visible light region becomes large, and various colors may be seen and the visibility may be deteriorated (coloring phenomenon). ..
  • the standard deviation of the Re value of the flat resin plate and the resin plate having a curved surface is small because the variation of the Re value is small. If the standard deviation of the Re value is sufficiently small, when the liquid crystal display protective plate on the liquid crystal screen is observed through the polarizing filter, the color unevenness caused by the variation of the Re value is suppressed and the visibility is improved.
  • the standard deviation of the Re value of the flat resin plate is preferably 15.0 nm or less, more preferably 10.0 nm or less, still more preferably 7.0 nm or less, particularly preferably 5.0 nm or less, and most preferably 4.0 nm or less. be.
  • the standard deviation of the Re value of the resin plate having a curved surface is preferably 25.0 nm or less, more preferably 20.0 nm or less, particularly preferably 15.0 nm or less, and most preferably 10.0 nm or less.
  • the thermoforming temperature is preferably Tg B or more and Tg A or less, and more preferably Tg B or more and less than Tg A.
  • the absolute value of the rate of change of the Re value after heating with respect to that before heating is preferably 50% or less, more preferably 40% or less, still more preferably. It is 30% or less, particularly preferably 25% or less, and most preferably 20% or less.
  • the standard deviation of the Re value within the range of 17 cm in width and 22 cm in length is preferably 25.0 nm or less, more preferably 20.0 nm or less. It is particularly preferably 15.0 nm or less, and most preferably 10.0 nm or less.
  • the total thickness (d) of the flat resin plate and the resin plate having a curved surface is not particularly limited, and is preferably 0.2 to 6.0 mm, more preferably 0.3 to 4.0 mm, and particularly preferably 0.4 to. It is 3.0 mm. If it is too thin, the rigidity of the liquid crystal display protective plate may be insufficient, and if it is too thick, it may hinder the weight reduction of the liquid crystal display or the touch panel display including the liquid crystal display.
  • phase difference adjustment layer The flat resin plate and the resin plate having a curved surface include a phase difference adjusting layer.
  • the phase difference adjusting layer is a layer that mainly determines the Re value of the liquid crystal display protective plate, and contains a transparent thermoplastic resin (A) having specific optical characteristics.
  • the absolute value of the photoelastic coefficient of the transparent thermoplastic resin (A) (C A) is a 10.0 ⁇ 10 -12 / Pa or less, preferably 8.0 ⁇ 10 -12 / Pa or less, more preferably 6 It is 0.0 ⁇ 10-12 / Pa or less, particularly preferably 5.0 ⁇ 10-12 / Pa or less, and most preferably 4.0 ⁇ 10-12 / Pa or less. If the absolute value of photoelastic coefficient (C A) is at more than the above upper limit, the stress-induced birefringence of residual stress generated during molding of the extrusion molding small (see FIG. 7.), A liquid crystal display protective plate The standard deviation of the Re value of can be reduced. As a result, when the liquid crystal display protective plate on the liquid crystal screen is observed through the polarizing filter, color unevenness due to variation in the Re value is suppressed, and visibility is improved.
  • the absolute value of the orientation double refraction ( ⁇ n A ) of the transparent thermoplastic resin (A) is 10.0 ⁇ 10 -4 to 100.0 ⁇ 10 -4 , preferably 20.0 ⁇ 10 -4 to 90. It is 0 ⁇ 10 -4 , more preferably 30.0 ⁇ 10 -4 to 70.0 ⁇ 10 -4 , and particularly preferably 35.0 ⁇ 10 -4 to 60.0 ⁇ 10 -4 .
  • the absolute value of the orientation birefringence ( ⁇ n A ) of the transparent thermoplastic resin (A) is within the above range, the Re value of the liquid crystal display protective plate can be controlled within an appropriate range. Since the orientation birefringence depends on the degree of orientation of the polymer, it is affected by manufacturing conditions such as molding conditions and stretching conditions. Unless otherwise specified in the present specification, "orientation birefringence" shall be measured by the method described in the section [Example] below.
  • Transparent thermoplastic resin (A) if a transparent thermoplastic resin which satisfies the range of photoelastic coefficient specified in the present invention (C A) and orientation birefringence ([Delta] n A), is not particularly limited.
  • the transparent thermoplastic resin (A) can contain one or more aromatic vinyl monomer units.
  • the aromatic vinyl monomer is not particularly limited, and styrene (St); nuclear alkyl substitutions such as 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 4-ethylstyrene, and 4-tert-butylstyrene.
  • Styrene ⁇ -alkyl substituted styrene such as ⁇ -methylstyrene and 4-methyl- ⁇ -methylstyrene and the like can be mentioned.
  • styrene (St) and / or ⁇ -methylstyrene are preferable from the viewpoint of availability.
  • V ⁇ T a Transparent thermoplastic resin
  • C A photoelastic coefficient
  • the stress birefringence is substantially zero.
  • the transparent thermoplastic resin (A) contains an aromatic vinyl monomer unit such as a styrene (St) unit
  • the orientation birefringence ( ⁇ n A ) is an aromatic vinyl monomer unit in the transparent thermoplastic resin (A).
  • Content V [% by mass] tends to depend on.
  • V ⁇ T A is strongly correlated with Re value of the liquid crystal display protection panel. If V ⁇ T A satisfies the above formula (1), it is possible to control the Re value of the liquid crystal display protective plate to a suitable range.
  • the V ⁇ T A preferably 6.0 to 30.0 more preferably 8.0 to 25.0, particularly preferably 10.0 to 20.0, most preferably at 12.0 to 18.0 ..
  • the transparent thermoplastic resin (A) includes a methacrylic acid ester unit such as a methyl methacrylate (MMA) unit; an acid anhydride unit such as a maleic anhydride unit; and an acrylonitrile unit. It may be a copolymer having a monomer unit of.
  • Specific examples of the transparent thermoplastic resin (A) containing an aromatic vinyl monomer unit include methacrylic acid ester-styrene copolymer (MS resin); styrene-maleic anhydride copolymer (SMA resin); styrene-.
  • Methacrylic acid ester-maleic anhydride copolymer SMM resin
  • ⁇ StMM resin ⁇ -methylstyrene-maleic anhydride-methacrylic acid ester copolymer
  • AS resin acrylonitrile-styrene copolymer
  • acrylicimide resin etc.
  • Examples of commercially available products of the above resin include the following products.
  • MS resin "Toyo MS” manufactured by Toyo Styrene Co., Ltd., etc.
  • SMA resin Daicel-Evonik “Plexiglas FT15", Polyscope "XIBOND”, “XIRAN”, etc.
  • SMM resin Denka's "Registry”, etc.
  • AS resin Nippon A & L Inc. "Lightac-A”, etc.
  • Acrylicimide resin Daicel-Evonik's "Pleximid” etc.
  • Transparent thermoplastic resin (A) as long as it satisfies the range of photoelastic coefficient specified in the present invention (C A) and orientation birefringence ([Delta] n A), a resin containing no aromatic vinyl monomer unit There may be.
  • the transparent thermoplastic resin (A) containing no aromatic vinyl monomer unit includes a methacrylic acid ester unit such as a methyl methacrylate unit, a glutarimide unit, an N-substituted or unsubstituted mylemid unit, and a lactone ring unit. Examples thereof include highly modified methacrylic resins containing at least one unit of choice. These can be used alone or in combination of two or more.
  • Transparent thermoplastic resin (A) is a resin containing an aromatic vinyl monomer unit satisfying the range of photoelastic coefficient (C A) and orientation birefringence ([Delta] n A) specified in the present invention, defined in the present invention or it may be a mixture of a photoelastic coefficient (C a) and does not contain an aromatic vinyl monomer unit satisfying the range of orientation birefringence ([Delta] n a) resin (modified methacrylic resin).
  • general methacrylic resins (non-modified methacrylic resins) and polycarbonate resins other than the above have a photoelastic coefficient and / or orientation birefringence outside the specified range of the present invention, and are transparent thermoplastic resins.
  • the polycarbonate resin has a very large absolute value of the photoelastic coefficient of 90 ⁇ 10-12 / Pa, and the Re value changes with a slight stress. Therefore, when a polycarbonate resin is used, it is difficult to obtain an optically uniform liquid crystal display protective plate. For example, when observing the liquid crystal display protective plate on the liquid crystal screen through a polarizing filter, color unevenness may be observed due to the variation in the Re value.
  • thermoforming step includes, for example, a step of heating the resin plate, a step of pressing the mold against the heated resin plate, a step of cooling the resin plate in the mold, and a step of taking out the cooled resin plate from the mold.
  • strain residual stress
  • a resin plate using a polycarbonate resin having a large absolute value of the photoelastic coefficient remarkable retardation unevenness occurs due to residual stress generated in the cooling process of thermoforming, and the variation in the Re value of the resin plate tends to increase.
  • the absolute value of the photoelastic coefficient of the methacrylic resin is as small as 3.2 ⁇ 10-12 / Pa, and the Re value does not easily change due to stress. Therefore, when a methacrylic resin is used, an optically uniform liquid crystal display protective plate can be obtained. However, since the absolute value of the orientation birefringence of the methacrylic resin is as small as 4.0 ⁇ 10 -4 , the Re value of the obtained liquid crystal display protective plate tends to be as small as about 20 nm, although it depends on the thickness.
  • the total thickness of the phase difference adjusting layer (T A) is not particularly limited, preferably 0.05 ⁇ 1.0 mm, more preferably 0.1 ⁇ 0.7 mm, particularly preferably 0.2 ⁇ 0.5 mm, most It is preferably 0.3 to 0.4 mm.
  • the retardation adjusting layer may contain, in a small amount, one or more other polymers whose photoelastic coefficient and / or orientation birefringence is out of the scope of the transparent thermoplastic resin (A).
  • the type of other polymer is not particularly limited, and is not particularly limited.
  • Polycarbonates, polyetherimides, and other thermoplastic resins such as polyacetal; thermocurable resins such as phenolic resins, melamine resins, silicone resins, and epoxy resins.
  • Examples of general non-denatured methacrylic resins include resins obtained by copolymerizing MMA with a small amount of methyl acrylate.
  • the content of the transparent thermoplastic resin (A) in the retardation adjusting layer is preferably large, preferably 90% by mass or more, more preferably 95% by mass or more, and particularly preferably 98% by mass or more.
  • the content of the other polymer in the retardation adjusting layer is preferably 10% by mass or less, more preferably 5% by mass or less, and particularly preferably 2% by mass or less.
  • the phase difference adjusting layer can contain various additives, if necessary.
  • Additives include colorants, antioxidants, thermal degradation inhibitors, UV absorbers, light stabilizers, lubricants, mold release agents, polymer processing aids, antistatic agents, flame retardants, light diffusers, and matting agents. Examples thereof include rubber components (impact resistance modifiers) such as agents, core-shell particles and block copolymers, and phosphors.
  • the content of the additive can be appropriately set as long as the effect of the present invention is not impaired.
  • the content of the antioxidant is 0.01 to 1 part by mass
  • the content of the ultraviolet absorber is 0.01 to 3 parts by mass
  • the light stabilizer is 100 parts by mass with respect to 100 parts by mass of the constituent resin of the retardation adjusting layer.
  • the content is preferably 0.01 to 3 parts by mass, and the content of the lubricant is preferably 0.01 to 3 parts by mass.
  • the timing of addition may be during or after the polymerization of the transparent thermoplastic resin (A).
  • the phase difference adjusting layer may be a resin layer made of a resin composition containing a transparent thermoplastic resin (A) and a known rubber component (impact resistance modifier).
  • the rubber component include multi-layer polymer particles having a core-shell structure, a rubber-like polymer having a salami structure, and a block polymer.
  • the rubber component may contain a diene-based monomer unit, an alkyl acrylate-based monomer unit, and the like. From the viewpoint of the transparency of the phase difference adjusting layer, it is preferable that the difference between the refractive index of the rubber component and the refractive index of the transparent thermoplastic resin (A) as the main component is smaller.
  • the glass transition temperature (Tg A ) of the phase difference adjusting layer is not particularly limited as long as Tg A > Tg B is satisfied. It is preferably 90 to 170 ° C, more preferably 100 to 160 ° C, particularly preferably 110 to 155 ° C, and most preferably 130 to 155 ° C.
  • the "glass transition temperature (Tg A ) of the phase difference adjusting layer” is the entire constituent material of the phase difference adjusting layer composed of one or more kinds of transparent thermoplastic resin (A) and, if necessary, one or more kinds of arbitrary components. The glass transition temperature of.
  • Tg A and Tg B are preferably 5 to 70 ° C, more preferably 10 to 50 ° C, particularly preferably 15 to 45 ° C, and most preferably 20 to 40 ° C.
  • Tg A- Tg B is within the above range, the resin plate can be satisfactorily thermoformed while suppressing the change in the Re value of the resin plate, as described in detail below, and the obtained curved surface is further formed. It is possible to suppress the deformation of the liquid crystal display protective plate.
  • thermoforming can be preferably performed at a temperature of Tg B or more and Tg A or less. It is more preferable to perform thermoforming at a temperature of Tg B + 10 ° C to Tg B + 30 ° C. Within this temperature range, the resin plate can be satisfactorily thermoformed into a desired shape, and the residual stress generated in the thermoforming cooling step can be suppressed to a small value. In this case, the change in the Re value can be suppressed, and the deformation of the obtained curved liquid crystal display protective plate can be suppressed. For example, when a reliability test of an in-vehicle display (for example, 1000 hours at 105 ° C. or 72 hours at 85 ° C. 85% RH) is carried out on a curved liquid crystal display protective plate, deformation due to release of residual stress is suppressed, which is preferable.
  • an in-vehicle display for example, 1000 hours at 105 ° C. or 72 hours at 85 ° C. 85% RH
  • thermoforming within the range of Tg B + 10 ° C. to Tg B + 30 ° C. and at a temperature lower than Tg A.
  • Tg A the stress and orientation of the retardation adjustment layer are not released, so that the change in the Re value and the deformation of the curved liquid crystal display protective plate are effectively suppressed, which is preferable.
  • thermoformed at a temperature of Tg B + 10 ° C. it is difficult to thermoform the resin plate into a desired shape. Even in this temperature range, if a large load is applied or the molding time is lengthened, thermoforming can be performed into a desired shape, but a large molding stress is generated in the resin plate.
  • a reliability test of an in-vehicle display is carried out on a curved liquid crystal display protective plate obtained under these conditions, a large residual stress is released and there is a risk of large deformation.
  • the flat resin plate and the resin plate having a curved surface include a base material layer having a lower glass transition temperature (Tg) than the retardation adjusting layer.
  • the base material layer can increase the overall thickness (d) of the resin plate and improve the rigidity of the resin plate.
  • the base material layer is preferably a resin layer that does not affect the Re value of the liquid crystal display protective plate, and is a resin layer containing a transparent thermoplastic resin (B) having a sufficiently small photoelastic coefficient and orientation birefringence. Is preferable.
  • the orientation birefringence ( ⁇ n B ) of the transparent thermoplastic resin (B) is preferably small, preferably less than 10.0 ⁇ 10 -4 , more preferably 8.0 ⁇ 10 -4 or less, still more preferably 6.0. It is ⁇ 10 -4 or less, particularly preferably 4.0 ⁇ 10 -4 or less, and most preferably 2.0 ⁇ 10 -4 or less.
  • the absolute value of the orientation birefringence ( ⁇ n B ) of the transparent thermoplastic resin (B) is not more than the above upper limit value, the influence on the Re value of the resin plate is sufficiently small (see FIG. 7), and the resin.
  • the Re value of the plate can be well controlled within an appropriate range.
  • Transparent thermoplastic resin (B) if a transparent thermoplastic resin which satisfies the range of photoelastic coefficient specified in the present invention (C B) and orientation birefringence ([Delta] n B), are not particularly limited. Specific examples include a general non-denatured methacrylic resin (PM), a modified methacrylic resin modified with a glutarimide unit, an N-substituted or unsubstituted mylemid unit, a lactone ring unit, and a cycloolefin polymer (COP). ) Etc. can be mentioned.
  • the transparent thermoplastic resin (B) can be used alone or in combination of two or more.
  • the methacrylic resin (PM) is a homopolymer or a copolymer containing a structural unit derived from one or more kinds of methacrylic acid esters. From the viewpoint of transparency, the content of the methacrylic acid ester monomer unit in the methacrylic acid resin (PM) is preferably 50% by mass or more, more preferably 80% by mass or more, and particularly preferably 90% by mass or more. , 100% by mass.
  • Preferred methacrylic acid esters include, for example, methyl methacrylate (MMA), ethyl methacrylate, butyl methacrylate, phenyl methacrylate, benzyl methacrylate, 2-ethylhexyl methacrylate, 2-hydroxyethyl methacrylate; monocyclic fatty acid methacrylate.
  • Hydrocarbic acid ester examples thereof include methacrylic acid polycyclic aliphatic hydrocarbon ester.
  • the methacrylic resin (PM) preferably contains MMA units, and the content of MMA units in the methacrylic resin (PM) is preferably 50% by mass or more, more preferably 80% by mass or more. Particularly preferably, it is 90% by mass or more, and may be 100% by mass.
  • the methacrylic resin (PM) may contain a structural unit derived from one or more other monomers other than the methacrylic acid ester.
  • Other monomers include methyl acrylate (MA), ethyl acrylate, butyl acrylate, cyclohexyl acrylate, phenyl acrylate, benzyl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate and the like.
  • MA is preferable from the viewpoint of transparency.
  • a copolymer of MMA and MA has excellent transparency and is preferable.
  • the content of MMA in this copolymer is preferably 80% by mass or more, more preferably 85% by mass or more, particularly preferably 90% by mass or more, and may be 100% by mass.
  • the methacrylic resin (PM) is preferably obtained by polymerizing one or more methacrylic acid esters containing MMA and, if necessary, other monomers.
  • a plurality of types of monomers usually, a plurality of types of monomers are mixed to prepare a monomer mixture, and then polymerization is performed.
  • the polymerization method is not particularly limited, and from the viewpoint of productivity, a radical polymerization method such as a bulk polymerization method, a suspension polymerization method, a solution polymerization method, and an emulsion polymerization method is preferable.
  • thermoplastic resin (B) As a transparent thermoplastic resin (B), illustrated type as the transparent thermoplastic resin (A) Resins (specifically, MS resin, SMA resin, SMM resin, AS resin, modified methacrylic resin, etc.) may be used. Depending on the monomer composition or the modification rate, the type of resin exemplified as the transparent thermoplastic resin (A) may be used as the transparent thermoplastic resin (B).
  • Resins specifically, MS resin, SMA resin, SMM resin, AS resin, modified methacrylic resin, etc.
  • the type of resin exemplified as the transparent thermoplastic resin (A) may be used as the transparent thermoplastic resin (B).
  • the polycarbonate-based resin is not included in the transparent thermoplastic resin (B) because the photoelastic coefficient and the orientation birefringence are outside the specified range of the present invention.
  • the polycarbonate resin has a very large absolute value of the photoelastic coefficient of 90 ⁇ 10-12 / Pa, and the Re value changes with a slight stress. Therefore, when a polycarbonate resin is used, it is difficult to obtain an optically uniform liquid crystal display protective plate. For example, when observing the liquid crystal display protective plate on the liquid crystal screen through a polarizing filter, color unevenness may be observed due to the variation in the Re value. In particular, after thermoforming, the change in the Re value of the resin plate is large compared to before thermoforming, and the variation in the Re value of the resin plate tends to be large.
  • the glass transition temperature of the phase difference adjusting layer is Tg A (° C) and the glass transition temperature of the substrate layer is Tg B (° C)
  • the glass transition temperature (Tg B ) of the base material layer is not particularly limited as long as Tg A > Tg B is satisfied. It is preferably 70 to 160 ° C, more preferably 100 to 150 ° C, particularly preferably 110 to 140 ° C, and most preferably 110 to 130 ° C.
  • the "glass transition temperature (Tg B ) of the base material layer” is the glass of all the constituent materials of the base material layer composed of one or more kinds of transparent thermoplastic resins (B) and, if necessary, one or more kinds of arbitrary components. The transition temperature.
  • the thickness (T B) of the base material layer is greater is designed than the total thickness of the phase difference adjusting layer (T A).
  • the liquid crystal display protective plate of the present invention satisfies T A ⁇ T B.
  • the thickness of the substrate layer (T B) is not particularly limited if it meets the T A ⁇ T B, is designed appropriately in accordance with the desired thickness and rigidity of the liquid crystal display protection panel.
  • T B is preferably 0.05 ⁇ 5.0 mm, more preferably 0.5 ⁇ 4.0 mm, particularly preferably 1.0 ⁇ 3.0 mm, and most preferably 1.5 ⁇ 2.5 mm.
  • T B / T A> 1, preferably T B / T A ⁇ 1.2, more preferably T B / T A ⁇ 1.5, more preferably T B / T A ⁇ 2. 0, particularly preferably T B / T a ⁇ 5.0, and most preferably T B / T a ⁇ 7.0. If T A and T B are in the above relationship, is sufficiently large proportion of the thickness of the base layer to the total thickness of the resin sheet (d) (T B), suitable for the substrate layer during thermoforming curved molding Molding can be performed at a different temperature, which is preferable.
  • T A the total thickness of the phase difference adjusting layer than the thickness of the base material layer (T B) (T A) is large, the thermoforming temperature of the glass transition temperature (Tg B) near the base layer, a desired molding rate (vehicle Form rate) is difficult to achieve. In this case, it is necessary to thermoform the retardation adjustment layer above the glass transition temperature (Tg A). Under this temperature condition, the degree of orientation of the phase difference adjusting layer is lowered, the Re value is lowered, and blackout may occur when the liquid crystal display protective plate on the liquid crystal screen is observed through the polarizing filter. If T A ⁇ T B, it is possible to carry out the molding at a temperature suitable for the substrate layer during thermoforming, preferred.
  • the base material layer may contain, in a small amount, one or more other polymers whose photoelastic coefficient and / or orientation birefringence is out of the scope of the transparent thermoplastic resin (B).
  • the type of other polymer is not particularly limited, and is not particularly limited, such as polycarbonate resin, polyolefin such as polyethylene and polypropylene, polyamide, polyphenylene sulfide, polyether ether ketone, polyester, polysulfone, polyphenylene oxide, polyimide, polyetherimide, and polyacetal.
  • Other thermoplastic resins include thermocurable resins such as phenolic resins, melamine resins, silicone resins, and epoxy resins.
  • the content of the transparent thermoplastic resin (B) in the base material layer is preferably large, preferably 90% by mass or more, more preferably 95% by mass or more, and particularly preferably 98% by mass or more.
  • the content of the other polymer in the base material layer is preferably 10% by mass or less, more preferably 5% by mass or less, and particularly preferably 2% by mass or less.
  • the base material layer can contain various additives, if necessary. Examples of the types of additives and preferable addition amounts are the same as those of additives that can be used for the phase difference adjusting layer. When another polymer and / or an additive is added to the base material layer, the timing of addition may be during or after the polymerization of the transparent thermoplastic resin (B).
  • the base material layer may be a resin layer made of a resin composition containing a transparent thermoplastic resin (B) and a known rubber component (impact resistance modifier).
  • a transparent thermoplastic resin (B) and a known rubber component (impact resistance modifier).
  • the rubber component are the same as those of the rubber component that can be used for the phase difference adjusting layer. From the viewpoint of the transparency of the base material layer, it is preferable that the difference between the refractive index of the rubber component and the refractive index of the transparent thermoplastic resin (B) as the main component is smaller.
  • the flat resin plate and the resin plate having a curved surface may have a resin layer other than the retardation adjusting layer and the base material layer.
  • the laminated structure of the resin plate includes a two-layer structure of a retardation adjustment layer-a base material layer; a three-layer structure of a retardation adjustment layer-a base material layer-a retardation adjustment layer; Three-layer structure of resin layer; three-layer structure of other resin layer-phase difference adjustment layer-base material layer; four-layer structure of phase difference adjustment layer-base material layer-phase difference adjustment layer-other resin layer; phase difference Examples thereof include a four-layer structure of an adjusting layer-a base material layer-another resin layer-a retardation adjusting layer.
  • the liquid crystal display protective plate and the liquid crystal display protective plate with a curved surface of the present invention can have a cured film formed on at least one of the outermost surfaces, if necessary.
  • the timing of forming the cured film may be before or after the curved surface processing.
  • a curved surface may be processed after forming a cured film on at least one surface of the flat liquid crystal display protective plate, or at least the curved liquid crystal display protective plate obtained by curving the flat liquid crystal display protective plate.
  • a cured film may be formed on one surface.
  • the cured film can function as a scratch resistant layer (hard coat layer) or a low reflective layer for the effect of improving visibility.
  • the cured film can be formed by a known method. Examples of the material of the cured film include inorganic, organic, organic-inorganic, and silicone-based materials, and organic-based and organic-inorganic-based materials are preferable from the viewpoint of productivity.
  • the inorganic cured film is formed by forming an inorganic material such as a metal oxide such as SiO 2 , Al 2 O 3 , TIO 2 , and ZrO 2 by vapor deposition such as vacuum deposition and sputtering. be able to.
  • an inorganic material such as a metal oxide such as SiO 2 , Al 2 O 3 , TIO 2 , and ZrO 2
  • vapor deposition such as vacuum deposition and sputtering.
  • a paint containing a resin such as a melamine resin, an alkyd resin, a urethane resin, and an acrylic resin is applied and heat-cured, or a paint containing a polyfunctional acrylic resin is applied. It can be formed by curing with ultraviolet rays.
  • the organic-inorganic cured film is coated with an ultraviolet curable hard coat paint containing inorganic ultrafine particles such as silica ultrafine particles having a photopolymerization-reactive functional group introduced on the surface and a curable organic component, and is irradiated with ultraviolet rays. It can be formed by polymerizing a curable organic component and a photopolymerization-reactive functional group of inorganic ultrafine particles. In this method, a network-like crosslinked coating film in which the inorganic ultrafine particles are chemically bonded to the organic matrix and dispersed in the organic matrix can be obtained.
  • inorganic ultrafine particles such as silica ultrafine particles having a photopolymerization-reactive functional group introduced on the surface and a curable organic component, and is irradiated with ultraviolet rays. It can be formed by polymerizing a curable organic component and a photopolymerization-reactive functional group of inorganic ultrafine particles.
  • the silicone-based cured film can be formed, for example, by polycondensing a partially hydrolyzed product such as carbon functional alkoxysilane, alkyltrialkoxysilane, and tetraalkoxysilane, or a material containing colloidal silica.
  • a partially hydrolyzed product such as carbon functional alkoxysilane, alkyltrialkoxysilane, and tetraalkoxysilane, or a material containing colloidal silica.
  • examples of the material coating method include various roll coats such as dip coats and gravure roll coats, flow coats, rod coats, blade coats, spray coats, die coats, and bar coats.
  • the resin plate When a thermosetting coating material is used, the resin plate can be exposed to a higher temperature than when other types of coating materials are used. If the curing temperature is insufficient, the curing reaction of the coating material may not proceed sufficiently, and the surface hardness of the cured coating or the adhesion to the resin plate may decrease. Even if the curing temperature is insufficient, if the curing time is lengthened, it may be sufficiently cured, but this is not preferable in terms of productivity. A sufficiently high curing temperature is required for the curing reaction to proceed satisfactorily, but when the curing temperature is higher than the glass transition temperature (Tg) of the underlying layer of the cured film, the underlying layer is thermally expanded. Since the coating material is cured, there is a possibility that the liquid crystal display protective plate may be wrinkled and / or the cured coating may be cracked.
  • Tg glass transition temperature
  • the resin plate included in the liquid crystal display protective plate of the present invention has a structure in which a phase difference adjusting layer having a relatively high glass transition temperature (Tg) is laminated on at least one surface of a base material layer.
  • a cured film can be formed on a retardation adjusting layer having a relatively high glass transition temperature (Tg) and excellent heat resistance. Therefore, the curing temperature is set within a temperature condition in which the retardation adjusting layer, which is the underlayer of the cured coating, does not thermally expand, that is, a temperature condition equal to or lower than the glass transition temperature (Tg) of the retardation adjusting layer, which is the underlayer of the cured coating. It can be set to a sufficiently high temperature at which the curing reaction proceeds well.
  • the curing temperature is preferably Tg B or more and Tg A or less, and more preferably Tg B or more and less than Tg A.
  • the present invention is particularly useful when forming a cured film using a thermosetting film material. According to the present invention, even when a cured film is formed using a thermosetting film material that requires a relatively high curing temperature, the surface hardness of the cured film and the adhesion to the resin plate are good, and the liquid crystal display A liquid crystal display protective plate containing a cured film without wrinkles and / or cracking of the cured film can be stably manufactured with good productivity.
  • the thickness of the scratch resistant (hard coat property) cured film is preferably 2 to 30 ⁇ m, more preferably 5 to 20 ⁇ m. If it is too thin, the surface hardness will be insufficient, and if it is too thick, cracks may occur due to bending during the manufacturing process.
  • the thickness of the low-reflection cured film is preferably 80 to 200 nm, more preferably 100 to 150 nm. If it is too thin or too thick, the low reflection performance may be insufficient.
  • liquid crystal display protective plate and the liquid crystal display protective plate with a curved surface of the present invention have known surface treatments such as an anti-glare (anti-glare) layer, an anti-reflection (anti-reflection) layer, and an anti-fingerprint layer on the surface thereof, if necessary.
  • Can have layers.
  • the method for manufacturing a flat liquid crystal display protective plate of the present invention is a step of forming a flat extruded resin plate in which a retardation adjusting layer having a relatively high glass transition temperature (Tg) is laminated on at least one surface of a base material layer (a step of forming a flat extruded resin plate. 1).
  • the method for manufacturing a flat liquid crystal display protective plate with a cured film includes the above step (1) and a step (2) of forming a cured film on at least one surface of the obtained extruded resin plate.
  • the flat resin plate having the laminated structure can be molded by a known method such as a cast molding method, an injection molding method, or an extrusion molding method. Above all, the coextrusion molding method is preferable.
  • FIG. 4 shows a schematic view of an extrusion molding apparatus including a T-die 11, first to third cooling rolls 12 to 14, and a pair of take-up rolls 15 as an embodiment.
  • the constituent resins of each layer are melt-kneaded using an extruder and co-extruded in a plate-like form from a T-die 11 having a wide discharge port in the form of a desired laminated structure.
  • Examples of the laminating method include a feed block method of laminating before the inflow of the T-die, a multi-manifold method of laminating inside the T-die, and the like.
  • the multi-manifold method is preferable from the viewpoint of improving the interfacial smoothness between layers.
  • the molten thermoplastic resin laminate co-extruded from the T-die 11 is pressurized and cooled by using the first to third cooling rolls 12 to 14.
  • the flat extruded resin plate 16 obtained after pressurization and cooling is taken up by a pair of take-up rolls 15.
  • the number of cooling rolls can be appropriately designed.
  • the configuration of the manufacturing apparatus can be appropriately redesigned as long as it does not deviate from the gist of the present invention.
  • the temperature of the entire resin on the third cooling roll 14 is defined as TX.
  • FIG. 4 schematically shows the measurement range of TX.
  • the temperature of the resin on the production line can be measured by a known method.
  • TX the surface temperature of the resin on the third cooling roll 14 can be measured using a non-contact thermometer such as an infrared radiation thermometer.
  • the Re value of the flat extruded resin plate is 50 to 330 nm.
  • the flat extruded resin plate is also molded so that the standard deviation of the Re value within the range of 17 cm in width and 22 cm in length is preferably 25.0 nm or less, more preferably 15.0 nm or less. ..
  • the orientation of the molecules is generated, for example, by the stress during molding near the glass transition temperature of the polymer.
  • Step (2) In the step (2), on at least one surface of the flat liquid crystal display protective plate obtained in the step (1) or the liquid crystal display protective plate thermoformed in the step (3) described later, inorganic or by a known method. Form an organic cured film. Since the method for forming the cured film has been described above, it is omitted here.
  • the cured film is preferably formed on a retardation adjusting layer having a relatively high glass transition temperature (Tg).
  • Tg glass transition temperature
  • the present invention is particularly useful when forming a cured film using a thermosetting film material.
  • a thermosetting material it is preferable to apply the thermosetting material on a flat resin plate and heat it at a temperature of Tg B or more and Tg A or less to form a cured film.
  • the curing temperature is set within a temperature condition in which the retardation adjusting layer, which is the underlayer of the cured coating, does not thermally expand, that is, a temperature condition lower than the glass transition temperature (Tg) of the retardation adjusting layer, which is the underlayer of the cured coating.
  • a method for manufacturing a flat liquid crystal display protective plate and a flat liquid crystal display protective plate with a cured film can have steps other than the above, if necessary.
  • the flat liquid crystal display protective plate obtained in the step (1) is cured.
  • Surface treatment such as primer treatment, sandblast treatment, and surface unevenness treatment such as solvent treatment; surface treatment such as corona discharge treatment, chromic acid treatment, ozone irradiation treatment, and surface oxidation treatment such as ultraviolet irradiation treatment on the surface forming the film. May be added.
  • the method for manufacturing a curved liquid crystal display protective plate of the present invention is as follows.
  • TY glass transition temperature
  • a cured film is formed on at least one surface of a flat liquid crystal display protective plate between steps (1) and (3), if necessary. It can have step (2).
  • step (3) a flat liquid crystal display protective plate with a cured film is thermoformed. Since the steps (1) and (2) have been described in the section [Method of manufacturing a liquid crystal display protective plate], they are omitted here.
  • Step (3) Shape processing such as curved surface processing on a flat liquid crystal display protective plate or a flat liquid crystal display protective plate with a cured film can be performed by known thermoforming such as press molding, vacuum forming, and pressure forming.
  • a flat liquid crystal display protective plate having a phase difference adjusting layer laminated on at least one surface of a base material layer is provided at a temperature of Tg B or more and Tg A or less, preferably Tg B super Tg A or less and less than TX. Thermoform.
  • the thermoforming temperature is TY. It is preferable that TX> TY and Tg B ⁇ TY ⁇ Tg A.
  • thermoforming at a temperature (TY) of Tg B or more and Tg A or less, more preferably to perform thermoforming at a temperature of Tg B super Tg A or less, and Tg B + 10 ° C. to Tg B +30. It is particularly preferable to perform thermoforming at a temperature of ° C.
  • the flat liquid crystal display protective plate can be satisfactorily thermoformed into a desired shape, and the residual stress generated in the cooling step of the thermoforming can be suppressed to a small value. In this case, the change in the Re value can be suppressed, and the deformation of the curved liquid crystal display protective plate obtained after thermoforming can be suppressed.
  • thermoforming is performed in the range of Tg B + 10 ° C. to Tg B + 30 ° C. and at a temperature lower than Tg A.
  • Tg A the stress and orientation of the retardation adjustment layer are not released, so that the change in the Re value and the deformation of the curved liquid crystal display protective plate are effectively suppressed, which is preferable.
  • thermoformed at a temperature of Tg B + 10 ° C. it is difficult to thermoform the extruded resin plate into a desired shape. Even in this temperature range, if a large load is applied or the molding time is lengthened, thermoforming can be performed into a desired shape, but a large molding stress is generated in the resin plate.
  • a reliability test of an in-vehicle display is carried out on a curved liquid crystal display protective plate obtained under these conditions, a large residual stress is released and there is a risk of large deformation.
  • thermoforming at a temperature lower than Tg A of the constituent resin of the phase difference adjusting layer of the extruded resin plate.
  • Tg A the temperature of the constituent resin of the phase difference adjusting layer of the extruded resin plate
  • the extruded resin plate in the extrusion molding step It was found that if the thermoforming temperature is higher than the temperature at which the orientation is controlled, the orientation of the resin is relaxed and the Re value may be significantly reduced.
  • the orientation of the retardation adjusting layer, which contributes to the magnitude of the Re value is, for example, extrusion molding of a resin plate having an overall thickness of 3 mm under the condition of a second cooling roll speed of 0.75 m / min. If so, it was found that it was formed by the third cooling roll. That is, in the present invention, TX is synonymous with "the temperature at which the orientation of the retardation adjusting layer, which contributes to the magnitude of the Re value during cooling in the extrusion molding process, is fixed". Therefore, the temperature (TX) of the entire resin on the third cooling roll can be used as the lower limit value of the "temperature that controls the orientation of the extruded resin plate in the extrusion molding step".
  • thermoforming When thermoforming is performed below TX, the resin temperature in the thermoforming step does not reach the resin temperature on the third cooling roll and the resin temperature on the upstream side of the third cooling roll. Under this condition, in the thermoforming process, the relaxation of the resin orientation is suppressed, the decrease in the Re value is effectively suppressed, and the visibility is reduced when the liquid crystal display protective plate on the liquid crystal screen is observed through the polarizing filter. Can be effectively suppressed.
  • the second cooling roll speed is coextruded under the condition of more than 0.75 m / min, the orientation of the retardation adjusting layer may be formed between the third cooling roll and the take-up roll. Further, even when the total thickness of the extruded resin plate to be molded is made thicker than 3 mm, the orientation of the retardation adjusting layer may be formed between the third cooling roll and the take-up roll.
  • step (1) molding is performed so that the Re value of the flat extruded resin plate is 50 to 330 nm.
  • the flat liquid crystal display protective plate is molded so that the standard deviation of the Re value within the range of 17 cm in width and 22 cm in length is preferably 25.0 nm or less, more preferably 15.0 nm or less.
  • the absolute value of the rate of change of the Re value after thermoforming with respect to that before thermoforming is preferably 50% or less, more preferably 40% or less, further preferably 30% or less, particularly preferably 25% or less, and most preferably 20%. It is as follows.
  • the curved liquid crystal display protective plate of the present invention obtained after thermoforming has a standard deviation of the Re value within a range of 17 cm in width and 22 cm in length, preferably 25.0 nm or less, more preferably 20.0 nm or less, and particularly preferably. Is 15.0 nm or less, most preferably 10.0 nm or less.
  • the lower limit of the radius of curvature of the curved surface included in the curved liquid crystal display protective plate of the present invention obtained after thermoforming is 50 mm, preferably 75 mm, more preferably 100 mm, particularly preferably 200 mm, and most preferably 300 mm.
  • the upper limit is 1000 mm, preferably 800 mm, more preferably 600 mm, particularly preferably 500 mm, and most preferably 400 mm.
  • the curved liquid crystal display protective plate having a Re value within a suitable range and a small variation in the Re value can be stably obtained. Can be manufactured to.
  • the Re value is within a suitable range both before and after thermoforming, the variation is small, and the liquid crystal display protective plate on the liquid crystal screen through the polarizing filter. It is possible to provide a liquid crystal display protective plate capable of suppressing deterioration of visibility such as color unevenness, blackout, and coloring when observing.
  • the liquid crystal display protection plate and the liquid crystal display protection plate with a curved surface of the present invention are, for example, ATMs of financial institutions such as banks; vending machines; televisions; mobile information of mobile phones (including smartphones), personal computers, tablet-type personal computers, etc. It is suitable as a protective plate for a liquid crystal display or a touch panel display used in digital information devices such as terminals (PDAs), digital audio players, portable game machines, copy machines, fax machines, and car navigation systems.
  • the liquid crystal display protective plate and the curved liquid crystal display protective plate of the present invention are suitable as, for example, a protective plate for an in-vehicle liquid crystal display.
  • the evaluation items and evaluation methods are as follows. (Content of aromatic vinyl monomer unit) The content (V mass%) of the aromatic vinyl monomer unit in the SMM resin, MS resin, or SMA resin is determined by 1 H-NMR method using a nuclear magnetic resonance apparatus (“400YH” manufactured by JEOL Ltd.). I asked. Deuterated chloroform was used as a solvent and tetramethylsilane was used as an internal standard substance, and the number of integrations was 64 times.
  • Glass transition temperature (Tg) of transparent thermoplastic resin The glass transition temperature (Tg) of the transparent thermoplastic resin was measured using a differential scanning calorimeter (“DSC-50”, manufactured by Rigaku Corporation). 10 mg of the transparent thermoplastic resin was placed in an aluminum pan and set in the above device. After performing nitrogen substitution for 30 minutes or more, the temperature was once raised from 25 ° C. to 200 ° C. at a rate of 20 ° C./min in a nitrogen stream of 10 ml / min, held for 10 minutes, and cooled to 25 ° C. (primary scan). ). Then, the temperature was raised to 200 ° C.
  • Tg glass transition temperature
  • the transparent thermoplastic resin was press-molded to obtain a resin plate having a thickness of 1.0 mm.
  • a test piece having a width of 15 mm and a length of 80 mm was cut out from the central portion of the obtained resin plate. Both ends of the test piece in the longitudinal direction were gripped by a pair of chucks. The distance between the chucks was 70 mm.
  • Tension was applied to the test piece using an "X-axis dovetail stage" manufactured by Oji Measuring Instruments Co., Ltd. The tension was gradually increased by 10N from 0N to 30N. The tension was monitored by "Sensor Separate Type Digital Force Gauge ZTS-DPU-100N" manufactured by Imada.
  • the phase difference value [nm] of the central portion of the test piece under tension was measured using "KOBRA-WR" manufactured by Oji Measuring Instruments Co., Ltd. under the condition of a measurement wavelength of 589.5 nm. After that, the test piece was removed from the pair of chucks, and the thickness (d [mm]) of the phase difference measuring portion was measured.
  • the transparent thermoplastic resin was press-molded to obtain a resin plate having a thickness of 1.0 mm.
  • a test piece having a width of 20 mm and a length of 50 mm was cut out from the central portion of the obtained resin plate and set in an autograph with a heating chamber (manufactured by SHIMADZU).
  • the distance between the chucks was 20 mm.
  • the thickness (d) is measured, and the Re value of the central portion is measured using "KOBRA-WR" manufactured by Oji Measuring Instruments Co., Ltd. at a measurement wavelength of 589. It was measured under the condition of 5 nm. The value of the orientation birefringence was calculated by dividing the obtained Re value by the thickness (d) of the test piece.
  • the average Re values of the liquid crystal display protective plate test piece (width 21 cm, length 30 cm) before curved surface molding and the liquid crystal display protective plate test piece (width 17 cm, length 22 cm) after curved surface molding are as follows. Values and standard deviations were measured.
  • a standard lens (FUJINON HF12.5HA-1B) was attached to "WPA-100-L" manufactured by Photonic Lattice. The height of the lens was adjusted so that the measurement range was 17 cm in width and 22 cm in length.
  • the Re value of the number of birefringent pixels of about 110,000 points was measured, and the average value and the standard deviation were obtained.
  • a test piece of the liquid crystal display protective plate was placed on the liquid crystal display so that the transmission axis of the polarizing element on the visual side of the liquid crystal display and the extrusion molding direction of the resin plate were perpendicular to each other. Further, a polarizing film was placed on the polarizing film, the polarizing film was rotated at various angles, and the appearance at the angle at which the color unevenness due to the variation in the Re value became the strongest was visually evaluated in the following three stages.
  • a test piece of the liquid crystal display protective plate was placed on the liquid crystal display so that the transmission axis of the polarizing element on the visual side of the liquid crystal display and the extrusion molding direction of the resin plate were perpendicular to each other. Further, a polarizing film was placed on the polarizing film, the polarizing film was rotated at various angles, and the appearance at the angle at which the transmitted light intensity of the liquid crystal display was minimized was visually evaluated in the following three stages.
  • a test piece of the liquid crystal display protective plate was placed on the liquid crystal display so that the transmission axis of the polarizing element on the visual side of the liquid crystal display and the extrusion molding direction of the resin plate were perpendicular to each other. Further, a polarizing film was placed on the polarizing film, the polarizing film was rotated at various angles, and the appearance at the angle at which the coloring of the liquid crystal display was maximized was visually evaluated in the following three stages.
  • the molding rate of the test piece (width 17 cm, length 22 cm) of the display protection plate with a curved surface was measured as follows. This will be described with reference to FIG.
  • the upper figure of FIG. 6 is a schematic cross-sectional view of a resin mold (male mold and female mold) used for molding a liquid crystal display protective plate with a curved surface, and is a yz cross-sectional view of FIG.
  • the lower figure of FIG. 6 is a schematic cross-sectional view of a liquid crystal display protective plate with a curved surface corresponding to the upper figure of FIG.
  • reference numeral 26 is a curved liquid crystal display protective plate
  • reference numeral M is a resin type.
  • a 50 mm square test piece was cut out from a liquid crystal display protective plate containing a cured film.
  • a super UV tester manufactured by Iwasaki Electric Co., Ltd .; SUV-W161
  • UV ultraviolet rays
  • the test piece is taken out from the testing machine, and the cured film is 1 mm 2 using a grid peeling test jig in an environment of a temperature of 23 ° C.
  • MS resin methyl methacrylate (MMA)
  • MS resin methyl methacrylate (MMA)
  • MS resin methyl methacrylate (MMA)
  • MMA methyl methacrylate
  • St a copolymer of styrene (St)).
  • ⁇ Methyl resin> The following methacrylic resins (methyl methacrylate (MMA) and methyl acrylate (methyl methacrylate (MMA)) and methyl acrylate (methyl methacrylate (MMA)) are according to the production method described in the [Example] section of International Publication No. 2017/146169, except that the compounding ratio of the monomer is changed. A copolymer with MA)) was polymerized.
  • thermoplastic resin laminate in which phase difference adjusting layers were laminated on both sides of the base material layer was co-extruded from the T-die.
  • This thermoplastic resin laminate is sandwiched between the first cooling roll and the second cooling roll adjacent to each other, wound around the second cooling roll, sandwiched between the second cooling roll and the third cooling roll, and the third It was cooled by wrapping it around a cooling roll.
  • the flat resin plate obtained after cooling was taken up by a pair of taking-up rolls. In this way, a liquid crystal display protective plate (reference drawing: FIG.
  • Tables 1 and 2 show the types and physical properties of the resin used, the total thickness of the retardation adjustment layer, the thickness of the base material layer, and the evaluation results of the liquid crystal display protective plate before curved surface molding for each example.
  • the conditions not shown in the table were set as common conditions.
  • a curved surface forming test piece having a width of 17 cm and a length of 22 cm was cut out from the central portion of the test piece so that the extrusion molding direction (resin flow direction) was the long side direction.
  • a curved surface was formed on this test piece as follows.
  • a resin mold manufactured using "Chemical Wood Prolab 65" manufactured by SSI Co., Ltd. was prepared.
  • the resin type M is composed of a combination of a female FM (lower type in the figure) and a male MM (upper type in the figure), and the overall shape is a width (dimension in the x direction in the figure) 200 mm ⁇ length.
  • a concave curved surface is formed on the upper surface of the female FM, a convex curved surface joined with the concave curved surface of the female FM is formed on the lower surface of the male MM, and the height of the female FM is 15 to 25 mm. The height was 20 to 10 mm.
  • a polytetrafluoroethylene (PTFE) sheet (300 mm ⁇ 300 mm ⁇ 12 mm) was placed in the oven, and the inside of the oven was heated to 170 ° C.
  • a test piece for curved surface forming is placed on a PTFE sheet, and the temperature of the test piece is the molding temperature shown in Table 3 (for example, using a non-contact thermometer (“PT-S80” manufactured by Optex)).
  • the temperature was maintained at 133 ° C. for 6 to 7 minutes.
  • the PTFE sheet and the curved surface forming test piece placed on the PTFE sheet were taken out from the oven.
  • Example 2 the temperature of the test piece immediately before being sandwiched between the female FM and the male MM was measured, and the molding temperature shown in Table 3 (for example, for example). In Example 1, it was confirmed that the temperature was 133 ° C.).
  • a test piece for curved surface molding at the above molding temperature is placed on a female FM at room temperature (20 to 25 ° C.), and a male MM at room temperature (20 to 25 ° C.) is placed on the test piece for curved surface molding. A load of 3 kg was applied. Then, the test piece was cooled to near room temperature over 1 to 2 minutes. The cooled test piece was taken out from the resin mold M, and the liquid crystal display protective plate (liquid crystal display protective plate with curved surface) after curved surface molding was evaluated using this test piece.
  • PT-S80 non-contact thermometer
  • Table 3 shows the thermoforming temperature and the evaluation results of the liquid crystal display protective plate after curved surface molding for each example.
  • the conditions not shown in the table were set as common conditions.
  • a silicone-based curable resin composition (“SilFORT PHC 587” manufactured by Momentive) is applied to the surface of one of the phase difference adjusting layers of the test piece as a thermosetting coating material. Then, it was dried at room temperature of 20 to 25 ° C. for 20 minutes, and then thermoset under the conditions of the curing temperature and the curing time shown in Table 4. In this way, a liquid crystal display protective plate containing a cured film was obtained.
  • Table 4 shows the conditions for forming the cured film and the evaluation results of the liquid crystal display protective plate containing the cured film. In each example of Table 4, the conditions not shown in the table were set as common conditions.
  • Example 8-2 Manufacturing of LCD protective plate
  • TX temperature of the entire resin on the third cooling roll would be the temperature shown in Table 6.
  • TX the surface temperature of the resin on the third cooling roll was measured using an infrared radiation thermometer.
  • FIG. 4 schematically shows the measurement range of TX.
  • a flat liquid crystal display protective plate having a three-layer structure in which phase difference adjusting layers are laminated on both sides of the base material layer was obtained. The thicknesses of the two phase difference adjusting layers were the same.
  • Table 5 shows the laminated structure, the type and physical properties of the resin used, the total thickness of the retardation adjusting layer, the total thickness of the base material layer, and the total thickness.
  • a test piece having a width of 17 cm and a length of 22 cm was cut out from the central portion of the obtained liquid crystal display protective plate so that the extrusion molding direction (resin flow direction) was the long side direction. Using this test piece, a flat liquid crystal display protective plate before thermoforming was evaluated.
  • test piece having the above molding temperature was placed on the female FM at room temperature (20 to 25 ° C.), and the male MM at room temperature (20 to 25 ° C.) was placed on the test piece, and 3 kg from above. I applied a load. Then, the test piece was cooled to near room temperature over 1 to 2 minutes. The cooled test piece was taken out from the resin mold M, and the curved liquid crystal display protective plate was evaluated using this test piece.
  • Table 6 shows the glass transition temperature (Tg) of the resin used, the temperature of the entire resin on the third cooling roll (TX) in the extrusion molding step, the thermoforming temperature (TY), and their temperature relationships.
  • Table 7 shows the evaluation results of the flat extruded resin plate and the curved liquid crystal display protective plate before thermoforming.
  • the absolute value of photoelastic coefficient (C B) is not more than 10.0 ⁇ 10 -12 / Pa
  • the absolute value of the orientation birefringence ([Delta] n B) is less than 10.0 ⁇ 10 -4
  • the average value of the Re value was 50 to 330 nm, and the standard deviation of the Re value was 15.0 nm or less.
  • the obtained liquid crystal display protective plate was used and the liquid crystal display protective plate on the liquid crystal screen was observed through a polarizing filter, color unevenness, coloring, and blackout were effectively suppressed.
  • Tg B temperature of Tg A or less
  • Tg B Tg A temperature of Tg B above Tg A or less
  • the average value of the Re values was 50 to 330 nm
  • the standard deviation of the Re values was 15.0 nm or less.
  • the absolute value of the rate of change of the average value of Re values after thermoforming with respect to that before thermoforming was 50% or less.
  • the obtained liquid crystal display protective plate with a curved surface was used and the liquid crystal display protective plate on the liquid crystal screen was observed through a polarizing filter, color unevenness, coloring, and blackout were effectively suppressed. ..
  • Example 8-2 the values of TX and TY are determined so as to satisfy the condition of thermoforming at a temperature (TY) of more than Tg B and less than Tg A and less than TX, and a flat liquid crystal display protective plate and a liquid crystal with a curved surface are determined.
  • a display protection plate Manufactured a display protection plate.
  • the average value of the Re value is 50 to 330 nm, and the standard deviation of the Re value is 25.0 nm or less (15.0 nm or less, 10.0 nm or less). rice field.
  • the curved liquid crystal display protective plate obtained in this embodiment has an average Re value of 50 to 330 nm and a standard deviation of the Re value of 25.0 nm or less (15.0 nm or less, 10.0 nm or less). rice field.
  • the absolute value of the rate of change of the Re value after thermoforming with respect to that before thermoforming was 50% or less (20% or less). Since the thermoforming temperature (TY) was lower than Tg A and TX of the phase difference adjusting layer resin, it is considered that the orientation of the phase difference adjusting layer resin was hardly distorted in the thermoforming step and the Re value was almost maintained. In this embodiment, when the curved liquid crystal display protective plate on the liquid crystal screen was observed through the polarizing filter, blackout, coloring, and color unevenness were effectively suppressed.
  • Tg A ⁇ Tg B was thermoformed at a temperature higher than Tg A and Tg B to produce a curved liquid crystal display protective plate.
  • the absolute value of the rate of change of the average Re value after thermoforming with respect to that before thermoforming was more than 50%.
  • the curved liquid crystal display protective plate obtained in this comparative example had a low Re value, and when the liquid crystal display protective plate on the liquid crystal screen was observed through a polarizing filter, blackout was noticeably observed.
  • Comparative Example 1-1 a cured film was formed on one surface of a flat liquid crystal display protective plate under the same curing conditions as in Examples 1 and 2.
  • the curing temperature was higher than the Tg of the retardation adjusting layer, and the coating material was cured in a state where the retardation adjusting layer was thermally expanded, so that the cured coating was cracked.
  • the curing temperature was lowered to a temperature lower than Tg of the phase difference adjusting layer. Although the cured film did not crack, the cross-linking reaction of the film material did not proceed sufficiently, and the surface hardness of the cured film and the adhesion of the cured film to the resin plate decreased.
  • Comparative Example 1-3 the curing temperature was lowered to a temperature lower than Tg of the phase difference adjusting layer, and the curing time was lengthened. Although the defective points of Comparative Examples 1-1 and 1-2 could be improved, the curing time was long and the productivity was poor.
  • Comparative Example 2 as the resin of the phase difference adjusting layer, the photoelastic coefficient (C A) and orientation birefringence ([Delta] n A) was used polycarbonate resin is defined outside of the present invention.
  • the flat liquid crystal display protective plate before curved surface forming obtained in this comparative example has a Re value larger than a suitable range, a large standard deviation of the Re value (large variation in the Re value), and is displayed on the liquid crystal screen through a polarizing filter. When observing the liquid crystal display protective plate in the above, color unevenness and coloring were remarkably observed.
  • Comparative Example 2 a flat liquid crystal display protection panel thermoformed at a temperature of Tg B above Tg A or less (less than Tg B than Tg A), was prepared a curved LCD display protective plate.
  • the absolute value of the rate of change of the average Re value after thermoforming with respect to that before thermoforming was more than 50%.
  • color unevenness was remarkably observed when the liquid crystal display protective plate on the liquid crystal screen was observed through a polarizing filter.
  • Comparative Example 2 a cured film was formed on one side of a flat liquid crystal display protective plate under the same curing conditions as in Examples 1 and 2.
  • the obtained cured film-containing liquid crystal display protective plate had a low surface hardness and was defective.
  • a cured film was formed on the polycarbonate resin layer. Since the surface hardness of the polycarbonate-based resin layer is low, even if a cured film is formed on the polycarbonate-based resin layer, high surface hardness cannot be obtained.
  • a liquid crystal display protective plate with a curved surface was manufactured by thermoforming at a temperature of Tg B or more and Tg A or less (Tg B or more and less than Tg A). In this comparative example, since the total thickness of the retardation adjusting layer is larger than the thickness of the substrate layer, the retardation adjusting layer is cracked at a molding temperature suitable for the substrate layer.
  • a liquid crystal display protective plate with a curved surface was manufactured by thermoforming at a temperature higher than Tg A and Tg B.
  • the absolute value of the rate of change of the average Re value after thermoforming with respect to that before thermoforming was more than 50%, and the standard deviation of the Re value after thermoforming was more than 25.0 nm.
  • the curved liquid crystal display protective plate obtained in this comparative example has a large standard deviation of the Re value (large variation in the Re value), and when the liquid crystal display protective plate on the liquid crystal screen is observed through the polarizing filter, the color unevenness is large. Was noticeably seen.
  • a cured film was formed on one side of a flat liquid crystal display protective plate under the same curing conditions as in Examples 1 and 2. In this comparative example, the curing temperature was higher than the Tg of the retardation adjusting layer, and the coating material was cured in a state where the retardation adjusting layer was thermally expanded, so that the cured coating was cracked.
  • the present invention is not limited to the above embodiments and examples, and the design can be appropriately changed as long as the gist of the present invention is not deviated.
  • Liquid crystal display protective plate 3 Liquid crystal display protective plate containing cured film 11 T-die 12-14 Cooling roll 15 Take-up roll 16A, 16B Flat resin plate 21 Phase difference adjustment layer 22 Base material layer 31 Cured film

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  • Nonlinear Science (AREA)
  • Mathematical Physics (AREA)
  • Chemical & Material Sciences (AREA)
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  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
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Abstract

La présente invention concerne une plaque de protection d'affichage à cristaux liquides capable de supprimer la dégradation de visibilité telle qu'une irrégularité de couleur, une extinction et une coloration lorsque ladite plaque de protection d'affichage à cristaux liquides sur un écran à cristaux liquides est observée à travers un filtre de polarisation. La plaque de protection d'affichage à cristaux liquides comprend une plaque de résine (16A) dans laquelle une couche de réglage de différence de phase (21) est stratifiée sur au moins une surface d'une couche de matériau de base (22). La couche de réglage de différence de phase comprend une résine thermoplastique transparente (A) ayant une valeur absolue d'un coefficient photoélastique de 10,0×10-12/Pa ou moins et ayant une valeur absolue de la biréfringence d'orientation de 10,0×10-4 à 100,0×10-4. La couche de matériau de base contient une résine thermoplastique transparente (B) ayant une valeur absolue d'un coefficient photoélastique de 10,0×10-12/Pa ou moins et ayant une valeur absolue d'une biréfringence d'orientation inférieure à 10,0×10-4. La Tg de la couche de réglage de différence de phase est supérieure à la Tg de la couche de matériau de base, et l'épaisseur de la couche de matériau de base est supérieure à l'épaisseur totale des couches de réglage de différence de phase. La valeur Re de la plaque de résine est de 50 à 330 nm.
PCT/JP2021/021659 2020-06-10 2021-06-08 Plaque de protection d'affichage à cristaux liquides, plaque de protection d'affichage à cristaux liquides à surface incurvée, et leurs procédés de fabrication WO2021251355A1 (fr)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2005352068A (ja) * 2004-06-09 2005-12-22 Toshiba Matsushita Display Technology Co Ltd 液晶表示装置
JP2011076026A (ja) * 2009-10-02 2011-04-14 Nippon Zeon Co Ltd 光学積層体
US20200004082A1 (en) * 2018-06-27 2020-01-02 Sharp Kabushiki Kaisha Liquid crystal display device

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2005352068A (ja) * 2004-06-09 2005-12-22 Toshiba Matsushita Display Technology Co Ltd 液晶表示装置
JP2011076026A (ja) * 2009-10-02 2011-04-14 Nippon Zeon Co Ltd 光学積層体
US20200004082A1 (en) * 2018-06-27 2020-01-02 Sharp Kabushiki Kaisha Liquid crystal display device

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