JP2005048058A - Plastic substrate and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plastic substrate causing no drop of its electrical conductivity even if formed an oriented film and causing no white spot trouble even if incorporated in an image display device, and to provide a method for producing the plastic substrate. <P>SOLUTION: The method for producing the plastic substrate having a coefficient of thermal expansion of ≤50 ppm/°C, a breaking elongation of 3-50% and a heat distortion temperature of ≥200°C comprises compounding a metal oxide in a polymer followed by conducting film formation, and carrying out a heat treatment of the resultant film at a temperature higher than the Tg of the polymer followed by another heat treatment at a temperature not lower than 50°C but lower than the Tg of the polymer for 3-200 h while applying tension of ≤20 kg/m onto the substrate. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  It is an object of the present invention to provide a plastic substrate suitable for manufacturing with a reduced layer structure and a method for manufacturing the same, in which conductivity is not lowered even when an alignment film is formed.

  In recent years, in the field of flat panel displays such as liquid crystal display elements, it has been studied to change the substrate from glass to a plastic substrate in order to improve breakage resistance, reduce the weight, and reduce the thickness. Since this substrate requires electrical conductivity, a metal film such as a semiconductor film such as indium oxide, tin oxide, or an oxide of tin-indium alloy, an oxide film of gold, silver, or palladium alloy on a plastic film, It has been studied to use a transparent conductive substrate provided with a film formed by combining the semiconductor film and the metal film as a transparent conductive layer as an electrode substrate of a liquid crystal display element.

  As the transparent conductive substrate, heat-resistant amorphous polymers such as modified polycarbonate (modified PC) (for example, Patent Document 1: JP 2000-227603 A), polyethersulfone (PES) (for example, Patent Document 2: JP 2000-284717 A), cycloolefin copolymer (for example, Patent Document 3: JP 2001-150584 A) and the like, in which a transparent conductive layer and a gas barrier layer are laminated, are known. It was. In these conductive substrates, after forming a transparent conductive film, it is necessary to form a polyimide film for aligning a liquid crystal layer by exposing it to a high temperature, and thus the above heat-resistant film is used.

  However, a substrate using the above heat-resistant film or heat-resistant polymer has not obtained sufficient heat resistance as a plastic substrate. That is, the glass transition temperature (hereinafter referred to as “Tg”) of these heat-resistant films exceeds 200 ° C., but after forming a conductive layer on these substrate films, at a temperature of 150 ° C. or more for forming an alignment film. When treated, there is a problem that both the conductivity and the gas barrier property are remarkably lowered.

  On the other hand, as a technique for solving the above problem, a technique of adding an inorganic compound having heat resistance to a plastic film has been attempted (for example, Patent Document 4: Japanese Patent Application Laid-Open No. 2001-14950). However, when this method is incorporated in a display element such as a liquid crystal or an organic EL, a white spot failure occurs, and thus further improvement is required.

JP 2000-227603 A (Claim 8, Claim 22, paragraphs [0009] to [0019]) JP 2000-284717 A (paragraphs [0010], [0021]) JP 2001-150584 A (paragraphs [0023] to [0025]) JP 2001-14950 A (claims 2 to 4, paragraphs [0007] and paragraphs [0015] to [0034])

  An object of the present invention is to provide a plastic substrate that does not deteriorate in conductivity even when an alignment film is formed, and that causes few white spot failures even when incorporated in an image display element, and a method for manufacturing the same.

  In order to solve the above-mentioned problems, the present inventors have intensively studied a technique for achieving both elongation at break and heat resistance. As a result, the present inventor has completed the present invention. That is, the object of the present invention is achieved by the following plastic substrate.

(1) The coefficient of thermal expansion is 1 to 50 ppm / ° C. or less, the elongation at break is 3 to 50%, and the heat distortion temperature is 200 to 400 ° C. Containing plastic substrate.
(2) The plastic substrate according to (1), wherein the metal oxide includes at least one of metal oxide particles having a particle diameter of 1 to 1000 nm and a metal oxide obtained by a sol-gel reaction.
(3) The plastic substrate according to (2), wherein the aspect ratio of the metal oxide particles is 1 to 10.
(4) The plastic substrate according to any one of (1) to (3), wherein the polymer is a thermosetting polymer.
(5) The plastic substrate according to any one of (1) to (4), wherein the surface average roughness (Ra) is 0.1 to 2 nm.
(6) The plastic substrate according to any one of (1) to (5), wherein the light transmittance is 75% or more and / or the retardation (Re) is 50 nm or less.
(7) The plastic substrate according to any one of (1) to (5), which has a thickness of 50 to 250 μm.
(8) A conductive plastic having a conductive layer having an electrical resistance of 1 to 100 Ω / sq on at least one surface of the plastic substrate according to any one of (1) to (7) substrate.
(9) The conductive plastic substrate according to (8), which has at least one 30-300 nm metal oxide layer formed in a vacuum.
(10) The conductive plastic substrate according to (8) or (9), which has at least one gas barrier layer.
(11) The conductive plastic substrate according to (10), wherein the water vapor transmission rate measured at 40 ° C. and 90% RH is 0.01 to 5 g / m ² · day.
(12) The conductive plastic substrate according to (10) or (11), wherein the oxygen permeability measured at 40 ° C. and 90% RH is 0.01 to 1 ml / m ² · day.
(13) A conductive polarizing plate characterized in that a polarizing film having an absorption axis inclined by 20 to 70 ° with respect to the longitudinal direction is laminated on the conductive plastic substrate according to any one of (8) to (12). .
(14) A λ / 4 plate comprising an optically anisotropic layer containing a liquid crystalline compound on the conductive plastic substrate according to any one of (8) to (12) or the conductive polarizing plate according to (13) A conductive λ / 4 plate, characterized by being laminated.
(15) At least two optically anisotropic layers are laminated, one of which has a retardation (Re) value at 550 nm of 240 to 300 nm, and the other one layer has a retardation (Re) value at 550 nm. The conductive λ / 4 plate according to (14), having a thickness of 80 to 170 nm.
(16) Any one of (1) to (7) is a λ / 4 plate comprising a polarizing film having an absorption axis inclined by 20 to 70 ° with respect to the longitudinal direction and an optically anisotropic layer formed of a liquid crystalline compound A circularly polarizing plate characterized by being laminated on the plastic substrate according to (8) or the conductive plastic substrate according to any one of (8) to (12).
(17) The plastic substrate according to any one of (1) to (7), the conductive plastic substrate according to any one of (8) to (12), the conductive polarizing plate according to (13), (14) or A liquid crystal display element using the conductive λ / 4 plate according to (15) and the circularly polarizing plate according to (16).
(18) The plastic substrate according to any one of (1) to (7), the conductive plastic substrate according to any one of (8) to (12), the conductive polarizing plate according to (13), (14 ) Or the conductive λ / 4 plate according to (15) and the circularly polarizing plate according to (16).
(19) The plastic substrate according to any one of (1) to (7), the conductive plastic substrate according to any one of (8) to (12), the conductive polarizing plate according to (13), (14 ) Or the conductive λ / 4 plate according to (15) and the circularly polarizing plate according to (16) are used.

The plastic substrate of the present invention can be obtained by the following production method.
(1) A method for producing a plastic substrate containing a metal oxide in a polymer, wherein after the substrate is formed, the substrate is heated at a temperature equal to or higher than Tg of the polymer while applying a tension of 1 to 20 kg to the substrate. A method of manufacturing a plastic substrate, characterized by performing a heat treatment.
(2) A method for producing a plastic substrate containing a metal oxide in a polymer, wherein after the substrate is formed, the substrate is heat-treated at a temperature of 50 ° C. or more and less than Tg of the polymer for 3 to 200 hours. A method for producing a plastic substrate characterized by the above.
(3) The manufacturing method according to (1), wherein a substrate obtained by heat treatment at a temperature of Tg or higher is heat-treated at a temperature of 50 ° C. or higher and lower than Tg of the polymer for 3 to 200 hours.
(4) The manufacturing method according to (2) or (3), wherein the heat treatment is performed after winding the substrate on a roll.
(5) The production method according to any one of (1) to (4), wherein a plasticizer is contained in an amount of 0.1 to 30% by mass with respect to the mass of the polymer when forming the substrate.
(6) The method according to any one of (1) to (5), wherein a silane coupling agent is contained in an amount of 0.1 to 10% by mass based on the mass of the polymer when forming the substrate.

  The plastic substrate of the present invention has a coefficient of thermal expansion of 1 to 50 ppm / ° C. or less, a breaking elongation of 3 to 50%, and a heat distortion temperature of 200 to 400 ° C. In the plastic substrate of the present invention, after the substrate is formed, the substrate is heat-treated at a temperature equal to or higher than Tg of the polymer while applying a tension of 1 to 20 kg / m to the substrate. It is obtained by heat-treating at a temperature of less than Tg for 3 to 200 hours. For this reason, if it is a plastic substrate of this invention, even if it forms a conductive layer on this board | substrate and provides alignment film, electroconductivity does not fall, and it has favorable heat resistance. Furthermore, when a gas barrier layer is formed, excellent gas barrier properties can be maintained even when an alignment film is provided, and a plastic substrate suitable for use in liquid crystal display elements, organic EL elements, and the like can be provided.

  Hereinafter, the plastic substrate and the manufacturing method thereof, the conductive plastic substrate, the conductive polarizing plate, the conductive retardation plate, and the circular polarizing plate of the present invention will be described in more detail. In the present specification, “to” is used as a meaning including numerical values described before and after the lower limit value and the upper limit value.

[Plastic substrate of the present invention]
<Polymer>
The polymer used in the plastic substrate of the present invention may be either a thermoplastic polymer or a thermosetting polymer. From the viewpoint of easy realization of higher heat resistance, a thermosetting polymer is preferably used.

(1) Thermoplastic polymer The thermoplastic polymer preferably has a Tg of 135 to 400 ° C, more preferably 150 to 360 ° C, more preferably 160 to 330 ° C. Some are more preferred. The thermoplastic polymer is preferably an amorphous polymer from the viewpoint of achieving optical uniformity. Examples of such thermoplastic polymers include the following (in parentheses indicate Tg).

  Polycarbonate (PC: 140 ° C.), alicyclic polyolefin (for example, ZEONOR 1600: 160 ° C. manufactured by Nippon Zeon Co., Ltd.), polyarylate (PAr: 210 ° C.), polyethersulfone (PES: 220 ° C.), polysulfone (PSF: 190 ° C.), cycloolefin copolymer (COC: compound of Example 1 of JP 2001-150584 A: 162 ° C.), fluorene ring-modified polycarbonate (BCF-PC: Example 4 of JP 2000-227603 A) Compound: 225 ° C.), alicyclic modified polycarbonate (IP-PC: compound of Example 5 of JP 2000-227603 A: 205 ° C.), acryloyl compound (Example 1 of JP 2002-80616 A) Compound: 300 ° C. or higher).

  Among these, preferred polymers are polyarylate (PAr), polyethersulfone (PES), f-polycarbonate (f-PC), c-polycarbonate (c-PC), and particularly preferred polymers are fluorene ring-modified polycarbonate. (BCF-PC), an alicyclic modified polycarbonate (IP-PC). Examples of the fluorene ring-modified polycarbonate (BCF-PC) include 2,2-bis (4-hydroxyphenyl) propane (bisphenol A) and a polycarbonate resin containing bisphenol represented by the following formula [I] as a bisphenol component.

In the formula [I], R ¹ , R ² , R ³ and R ⁴ are the same or different hydrogen atoms or methyl groups, and X is a cycloalkylene group having 5 to 10 carbon atoms and an araalkylene having 7 to 15 carbon atoms. A haloalkylene group having 1 to 5 carbon atoms. Specific examples of X include 1,1-cyclopentylene, 1,1-cyclohexylene, 1,1- (3,3,5-trimethyl) cyclohexylene, norbornane-2,2-diyl, and tricyclohexane as cycloalkylene groups. [5.2.1.0 ^2,6 ] decane-8,8′-diyl, particularly 1,1-cyclohexylene and 1,1- (3,3,5-trimethyl) cyclohexylene are preferably used. Examples of the aralkylene group include phenylmethylene, diphenylmethylene, 1,1- (1-phenyl) ethylene, and 9,9-fluorenylene. As the haloalkylene group, 2,2-hexafluoropropylene, 2,2- (1,1,3,3-tetrafluoro-1,3-dicyclo) propylene and the like are preferably used.

  The polycarbonate resin may be one kind or two or more kinds. Of these, 1,1- (3,3,5-trimethyl) cyclohexylene or 9,9-fluorenylene is preferable from the viewpoint of heat resistance and optical properties required for the liquid crystal display element. These bisphenol components can be used in combination of two or more.

  The polycarbonate resin may be a copolymer or may be used in combination of two or more. Examples of such a polycarbonate-based resin include a homopolymer in which the bisphenol component is (i) bisphenol A, (ii) bisphenol A, and X in the above formula [I] is 1,1- (3,3,5-trimethyl) More preferably, it is a copolymer comprising cyclohexylene or bisphenol which is 9,9-fluorenylene. The composition of this copolymer is preferably 10 to 90 mol% of bisphenol A.

(2) Thermosetting polymer Examples of the thermosetting polymer include epoxy resins and radiation curable resins. Examples of the epoxy resin include polyphenol type, bisphenol type, halogenated bisphenol type, and novolac type. A known curing agent can be used as the curing agent for curing the epoxy resin. Examples thereof include curing agents such as amines, polyaminoamides, acids and acid anhydrides, imidazoles, mercaptans, and phenol resins. Among them, from the viewpoints of solvent resistance, optical properties, thermal properties, etc., polymers or aliphatic amines containing acid anhydrides and acid anhydride structures are preferably used, and particularly preferred are acid anhydrides and acid anhydride structures. It is a polymer containing. Furthermore, it is preferable to add an appropriate amount of a known curing catalyst such as tertiary amines and imidazoles.

  A radiation curable resin is a resin that cures when irradiated with radiation such as ultraviolet rays and electron beams. Specifically, it is an unsaturated double molecule such as an acryloyl group, a methacryloyl group, or a vinyl group in a molecule or a single structure. A resin containing a bond. Among these, an acrylic resin containing an acryloyl group is particularly preferable. The radiation curable resin may be one kind of resin or a mixture of several kinds of resins, but an acrylic resin having two or more acryloyl groups in the molecule or unit structure should be used. Is preferred. Examples of such polyfunctional acrylate resins include, but are not limited to, urethane acrylates, ester acrylates, epoxy acrylates, and the like. In particular, an acrylic resin containing units of the following formula [II] and / or [III] and having at least two acryloyl groups is preferable.

また、特開２００２−２７５２８５号公報の実施例１〜２０に記載の熱硬化型樹脂も好ましく用いることができる。

Further, thermosetting resins described in Examples 1 to 20 of JP-A No. 2002-275285 can also be preferably used.

  In the case of using an ultraviolet curing method, an appropriate amount of a known photoreaction initiator can be added to these radiation curable resins.

<Metal oxide>
In the plastic substrate of the present invention, the type of metal oxide used is not particularly limited, and various metal oxides can be used. For example, when a metal oxide is dispersed in the polymer in the form of fine particles (fine particle method), the metal oxide is a colorless oxide such as silicon, aluminum, zinc, zirconium, indium, tin, titanium, or lead. It is preferable to use oxides of silicon, aluminum, zirconium and titanium. Among them, the metal oxide is preferably silicon oxide or aluminum oxide, and silicon oxide is particularly preferable.

  The size of the metal oxide particles is preferably 1 to 1000 nm, more preferably 3 to 300 nm, and even more preferably 5 to 100 nm. The particle diameter is represented by a sphere equivalent diameter. If the particle diameter is 1000 nm or less, good transparency can be obtained and a sufficient heat resistance effect can be obtained. Here, the “equivalent sphere diameter” means the diameter of the sphere when the size of the metal oxide particle is converted to a sphere having the same volume as the metal oxide particle.

  The metal oxide particles preferably have a small aspect ratio (average particle diameter / thickness) (not a flat plate). The aspect ratio is preferably 1 to 10, more preferably 1 to 8, and further preferably 1 to 5. The aspect ratio can be obtained from the average value obtained by photographing metal oxide particles with an electron microscope, measuring the thickness of 100 points, and the average particle diameter.

  Since the metal oxide adsorbs water on the surface and the dispersibility tends to decrease, it is preferable to use a metal oxide dried at 100 to 200 ° C. for 1 to 50 hours before adding it to the polymer.

  The metal oxide can be a metal oxide obtained by a sol-gel method. In this case, the metal oxide is obtained by a sol-gel reaction, that is, a metal alkoxide is hydrolyzed and / or hydrolyzed and polycondensed with an acid catalyst.

(A) Metal alkoxide In the sol-gel reaction, a metal alkoxide other than alkoxysilane and / or alkoxysilane is used. As the metal alkoxide other than alkoxysilane, it is preferable to use zirconium alkoxide, titanium alkoxide, aluminum alkoxide or the like. These can also be used in combination. Preferred combinations include, for example, (a) alkoxysilane alone, (b) alkoxysilane and alkoxyzirconium, and (c) aluminum alkoxide and / or titanium alkoxide. And the like. Specific examples of the alkoxysilane, zirconium alkoxide, aluminum alkoxide, and titanium alkoxide include the following.

(A) Alkoxysilane Examples of the alkoxysilane include silica alkoxides such as tetramethoxysilane, tetraethoxysilane, methyltriethoxysilane, and ethyltriethoxysilane, polymerizable metal alkoxides such as methylpropylacryltriethoxysilane, and glycidylpropyltri Examples thereof include metal alkoxides having functional groups such as ethoxysilane, aminopropyltriethoxysilane, phenyltriethoxysilane, and benzyltrimethoxysilane. Above all, the general formula Si (OR ¹⁾ ₄ (where, R ¹ is a lower alkyl group having 1 to 6 carbon atoms.) Is preferably an alkoxysilane represented by, for example, Si (OCH _{3) 4,} Si (OC ₂ H ₅ ) ₄ or the like is preferable.

(B) Zirconium alkoxide The zirconium alkoxide is preferably one represented by the general formula Zr (OR ² ) ₄ (wherein R ² is a lower alkyl group having 1 to 6 carbon atoms). Specifically, Zr (OCH ₃ ) ₄ , Zr (OC ₂ H ₅ ) ₄ , Zr (O-iso-C ₃ H ₇ ) ₄ , Zr (OC ₄ H ₉ ) _{4 and the} like can be mentioned. These zirconium alkoxides may be used in combination of two or more. When zirconium alkoxide is used in combination with the above alkoxysilane, the content of zirconium alkoxide is preferably 25 parts by mass or less with respect to 100 parts by mass of alkoxysilane.

(C) Aluminum alkoxide The aluminum alkoxide is preferably represented by triethoxyaluminum or the general formula Al ₂ (OR ³ ) ₃ (wherein R ³ is a lower alkyl group having 1 to 6 carbon atoms). Specific examples include Al ₂ (OCH ₃ ) ₃ , Al ₂ (OC ₂ H ₅ ) ₃ , Al ₂ (OC ₃ H ₇ ) ₃ , Al ₂ (OC ₄ H ₉ ) _{3 and the} like. These aluminum alkoxides may be used in combination of two or more. When aluminum alkoxide is used in combination with alkoxysilane, the content of aluminum alkoxide is preferably 25 parts by mass or less with respect to 100 parts by mass of alkoxysilane.

(D) Titanium alkoxide The titanium alkoxide is preferably trimethoxytitanium or a general formula Ti (OR ⁴ ) ₄ (wherein R ⁴ is a lower alkyl group having 1 to 6 carbon atoms). Specific examples include Ti (OCH ₃ ) ₄ , Ti (OC ₂ H ₅ ) ₄ , Ti (OC ₃ H ₇ ) ₄ , Ti (OC ₄ H ₉ ) _{4 and the} like. These titanium alkoxides may be used in combination of two or more. When titanium alkoxide is used in combination with alkoxysilane, the content of titanium alkoxide is preferably 5 parts by mass or less with respect to 100 parts by mass of alkoxysilane.

(B) Acid catalyst The acid catalyst used in the sol-gel reaction is preferably a mineral acid such as sulfuric acid, hydrochloric acid or nitric acid, and an organic acid such as acetic acid or tartaric acid. Among these, the acid catalyst is preferably an organic acid, and more preferably acetic acid, because it is necessary to react in the polymer as described later. The amount of the acid catalyst used is 0.001 to 0.005 mol per 1 mol of metal alkoxide (alkoxysilane and other metal alkoxide, when alkoxysilane and other metal alkoxide are contained), preferably about 0.01 mole.

  The sol-gel reaction is carried out under heating. In the present invention, as described later, it is preferable to carry out the heat treatment separately into a heat treatment of Tg or more and a heat treatment of less than Tg.

  When the metal oxide is contained in the polymer, it is preferable to use a silane coupling agent in order to uniformly disperse the metal oxide in the polymer. Examples of the silane coupling agent include N-β (aminoethyl) γ-aminopropylmethyldimethoxy of an amino silane such as vinyltriethoxysilane, vinyltrichlorosilane, vinyltris (β-methoxyethoxy) silane having an unsaturated bond. Of epoxy-based silanes such as silane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, etc. β (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltriethoxysilane, etc. γ- Tacryloxypropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-methacryloxypropyltriethoxysilane, etc., and γ-mercaptopropyltrimethoxysilane, γ-chloropropyl A trimethoxysilane etc. can be illustrated. Among these, an epoxy-based silane coupling agent is preferable from the viewpoint of easy handling.

  The addition amount of the silane coupling agent is preferably 0.1 to 10% by mass, and more preferably 1 to 5% by mass with respect to the mass of the polymer.

  The content of the metal oxide with respect to the mass of the polymer is suitably 10 to 70% by mass, more preferably 20 to 60% by mass, and still more preferably 30 to 55% by mass. If it is the range of 10-70 mass%, while being able to make the thermal expansion coefficient of a plastic substrate 50 ppm / degrees C or less as mentioned later, favorable transparency is obtained, it is preferable.

<Coefficient of thermal expansion>
Since the plastic substrate of the present invention contains the metal oxide in the polymer, the coefficient of thermal expansion is 1 to 50 ppm / ° C., preferably 1 to 40 ppm / ° C., more preferably 1 to 30 ppm / ° C. it can.

  Thermal expansion is a phenomenon in which the thermal expansion of the polymer is activated by the temperature rise, so that the free volume around the polymer molecule is increased, so that the volume expands. The decrease in conductivity in the conductive plastic substrate is mainly caused by the difference in thermal expansion coefficient between the plastic substrate and the conductive layer formed thereon. That is, the conductive layer is formed of a semiconductor film such as an oxide of indium oxide, tin oxide or tin-indium alloy, a metal film such as an oxide film of gold, silver or palladium alloy, or a combination of the semiconductor film and the metal film. These films have a coefficient of thermal expansion of 3-10 ppm / ° C. On the other hand, the coefficient of thermal expansion of the plastic substrate is 40 to 100 ppm / ° C., which is about 1/10 of the coefficient of thermal expansion of the conductive layer. When an alignment film made of polyimide is formed on the conductive layer to align the liquid crystal element, it is necessary to heat, but when the heating temperature exceeds the range of 150 to 170 ° C., the linear expansion coefficient of the plastic substrate and the conductive layer is increased. Due to the dimensional distortion caused, the conductive film is broken and the conductivity is lowered. In other words, the plastic base material tends to expand due to thermal expansion, whereas the conductive layer has a small elongation, so that the plastic base material is pulled and broken by the plastic substrate, resulting in a decrease in conductivity. Therefore, in the plastic substrate of the present invention, a metal oxide having a small thermal expansion coefficient is contained in the polymer. Since the plastic substrate containing a metal oxide can suppress the thermal motion of the polymer in the substrate due to the interaction between the metal oxide surface and the polymer molecule, the thermal expansion coefficient of the substrate can be reduced.

<Elongation at break>
In the plastic substrate of the present invention, the elongation at break is 3 to 50%, more preferably 4 to 45%, and still more preferably 5 to 40%.
The present inventor has found that a white spot failure that occurs during assembly of a liquid crystal display element is caused by chips generated during cutting of a plastic substrate. In other words, the present inventor has found that a fragile plastic substrate generates more chips, and the chips can be reduced by suppressing a decrease in elongation at break. The elongation at break in the range of 3 to 50% cannot be obtained simply by mixing the metal oxide and the polymer, but can be obtained by preparing by the method described later. This point will be described later.

  The elongation at break is, for example, after the sample is chucked at a predetermined interval (M), then pulled at a predetermined pulling speed, and from the tensile length (L) when the sample breaks, the breaking elongation (%) = (L / M) It can be calculated by x100.

<Heat deformation temperature>
The plastic substrate of the present invention suitably has a heat distortion temperature of 200 to 400 ° C, preferably 250 to 360 ° C, more preferably 300 to 330 ° C. The term “thermal deformation temperature” as used herein means a temperature at which the plastic substrate starts to grow suddenly due to the load when a certain load is applied to the plastic substrate and the temperature is raised.

  A plastic substrate containing no metal oxide, particularly a plastic substrate made of an amorphous polymer, undergoes a rapid elongation due to an increase in molecular mobility when the Tg of the polymer is exceeded. On the other hand, the plastic substrate containing a metal oxide does not generate any elongation as described above in the temperature range of several hundred degrees Celsius that is heat-treated. This is because if the metal oxide is not contained in the polymer, the interaction between polymer molecules in the plastic substrate is weak, slip between molecules occurs, and elongation (deformation) is likely to occur due to heat and load. It is. On the other hand, when the metal oxide is contained in the polymer, the surface of the metal oxide interacts with the polymer molecule, and this interaction force is greater than that between the polymer molecules. Elongation (deformation) can be suppressed, and the heat deformation temperature can be increased.

  The thermal deformation temperature is measured, for example, by measuring the dimensional change of the sample as the temperature rises using TMA (Thermal Mechanical Analysis) under a predetermined condition, and extrapolation lines of elongation below Tg and extrapolation of elongation above Tg The heat distortion temperature can be obtained from the intersection with the line.

  The thickness of the plastic substrate of the present invention is preferably 50 to 250 μm, more preferably 70 to 200 μm, and still more preferably 90 to 150 μm. If the thickness of the substrate is 50 μm to 250 μm, it is too thin to cause nicks and breaks during handling, and the thickness of the display element incorporating the plastic substrate of the present invention can be reduced.

  The light transmittance of the plastic substrate of the present invention is preferably a transparent film, that is, 75% or more, preferably 80% or more since the plastic substrate of the present invention is used as an image display element such as a display. Is preferable, and more preferably 90% or more. The haze (cloudiness value) of the plastic substrate of the present invention is preferably 3% or less, more preferably 2% or less, and more preferably 1% or less because it is used as an image display element such as a display. More preferably.

  The plastic substrate of the present invention preferably has an inner surface retardation (Re) of 0 to 50 nm, more preferably 0 to 40 nm, and even more preferably 0 to 30 nm. If the retardation (Re) is 50 nm or less, it is possible to reduce the unevenness of the visual field when the image display element is used.

  The plastic substrate of the present invention has a surface average roughness (Ra) of 0 to 2 nm, preferably 0 to 1.5 nm, and more preferably 0 to 1 nm. If the surface average roughness (Ra) is 2 nm or less, it is preferable to provide a conductive layer thereon by sputtering or the like because abnormal discharge between the electrodes due to surface irregularities can be reduced.

  The light transmittance and haze in the plastic substrate of the present invention can be achieved by using a silane coupling agent and minimizing the generation of voids at the interface between the polymer and the metal oxide. Furthermore, the average surface roughness (Ra) is caused by surface roughness caused by the metal oxide protruding from the surface when the plastic substrate is formed, and this is an affinity for the metal oxide to be sufficiently incorporated into the polymer. This is achieved by increasing the properties, i.e. coating the surface with a silane coupling agent. Retardation (Re) can be achieved by relaxing the oriented segments by a heat treatment of Tg or higher after the plastic substrate is formed, which will be described later.

[Plastic substrate manufacturing method of the present invention]
Next, the manufacturing method of the plastic substrate of this invention is demonstrated. Note that in this specification, a process for manufacturing a plastic substrate is referred to as “film formation”, and a process for forming an inorganic thin film by a vacuum method is referred to as “film formation”.

  The plastic substrate of the present invention forms a plastic substrate by containing a metal oxide in the polymer. In the production method of the present invention, the method of incorporating the metal oxide into the polymer may be any one of a fine particle method in which the metal oxide is finely dispersed in the polymer, and a sol-gel method in which the metal oxide is dispersed in the polymer using a sol-gel reaction. It may be a method.

  In the fine particle method, when the metal oxide and the silane coupling agent are melt film forming using a thermoplastic polymer, it is preferable to add and mix the polymer when the polymer is melt kneaded. That is, the metal oxide and the silane coupling agent are kneaded with a screw in a kneading extruder. On the other hand, in the case of solution film formation using a thermoplastic polymer, it is preferable to add and mix a metal oxide and a silane coupling agent when the polymer is dissolved in a solvent. In the case of a thermosetting polymer, it is preferable to add and mix a metal oxide and a silane coupling agent before curing. These mixings are achieved by using an ordinary mixer.

  In the sol-gel method, in order to disperse a metal oxide in a polymer, in the case of a thermoplastic polymer, a raw metal alkoxide and an acid catalyst can be dissolved and reacted in a solution in which the polymer is previously dissolved in a solvent. . That is, after sufficiently mixing and dissolving at room temperature so that the polymer concentration becomes 10 to 40% by mass, the sol-gel reaction solution is added thereto. The mixing ratio of the polymer to the sol-gel reaction liquid is such that the content of the obtained metal oxide with respect to the mass of the polymer after the sol-gel reaction is 10 to 70% by mass, more preferably 20 to 60% by mass, and still more preferably 30 to 55%. It is preferable to adjust so that it may become mass%.

  Examples of the solvent for dissolving the thermoplastic polymer include methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butanol and the like. It is preferable that the usage-amount of a solvent is 30-100 mass parts per 100 mass parts of total solid. Moreover, it is preferable to heat the said mixed solution at the temperature of 50-200 degreeC, Preferably it is 55-190 degreeC, More preferably, it is 60-180 degreeC.

  On the other hand, when the polymer is a thermosetting polymer, a sol-gel reaction liquid is added to these monomers. The content of the metal oxide obtained by the sol-gel reaction is 10 to 70% by mass, preferably 20 to 60% by mass, and more preferably 30 to 55% by mass with respect to the polymer component obtained by polymerization. .

  The plastic substrate of the present invention is formed by forming a plastic substrate and then heat-treating the substrate at a temperature of Tg or higher of the polymer while applying a tension of 1 to 20 kg (hereinafter referred to as “Tg or higher heat treatment”). Can be manufactured.

  By applying heat treatment at a temperature equal to or higher than the Tg of the polymer alone in a state where a certain tension is applied, the polymer forming the plastic substrate can be relaxed and made difficult to break. When the film is formed by a normal method, the polymer exists in a tensioned state due to residual strain during film formation. Since such a polymer is easily broken by a tensile stress, the elongation at break tends to be small. Therefore, in the method for producing a plastic substrate of the present invention, the tension of the polymer can be released by heat-treating the plastic substrate at a temperature higher than the Tg of the polymer alone.

  That is, since the polymer in tension is unstable with small entropy, it is heated to Tg of the polymer alone, more preferably Tg + 5 ° C. or more of the polymer alone, more preferably Tg + 10 ° C. or more of the polymer alone to increase the polymer mobility. To make the polymer a rounded molecular structure with low entropy. However, when a strong tension is applied at this time, the tension of the polymer cannot be relaxed, so that a tension of 1 to 20 kg / m, more preferably 1 to 10 kg / m, and further preferably 1 to 5 kg / m is applied. It is preferable to heat-treat.

  The heat treatment time for Tg or more is 1 to 60 minutes, preferably 2 to 40 minutes, and more preferably 3 to 20 minutes. If the heat treatment time exceeds 60 minutes, coloring may occur.

  The heat treatment above Tg may be carried out in the process of transporting the plastic substrate to the heat treatment zone, may be continued after the plastic substrate is formed, or may be carried out separately after being wound on a roll once. Good.

  The plastic substrate of the present invention is subjected to a heat treatment for 3 to 200 hours at a temperature of 50 ° C. or more and less than Tg of the polymer after the substrate obtained by heat treatment of Tg or more is wound on a roll (hereinafter referred to as “less than Tg heat treatment”). ").

  One of the reasons why the elongation at break is small and brittle is due to the presence of stress concentration points. That is, in order to improve brittleness, it is effective to reduce the voids existing in the plastic substrate, and in particular, to improve brittleness by reducing the gap (free volume) between the polymer and the metal oxide. be able to. An effective technique for reducing the free volume is a heat treatment less than Tg, which is 50 ° C. or more and less than the Tg of the polymer alone, preferably 100 ° C. or more and less than the Tg of the polymer alone, more preferably 140 ° C. or more. This can be achieved by performing a heat treatment for 3 to 200 hours, preferably 5 to 100 hours, more preferably 10 to 50 hours at a temperature lower than the single Tg.

  Since it is difficult to perform the heat treatment for a long time while being conveyed, the heat treatment is preferably performed in a heat treatment chamber after being wound into a roll. In the case of a plastic substrate that does not contain a metal oxide, such a heat treatment tends to make it brittle. This is because when the free volume in the plastic substrate is reduced, the gap in which molecules flow and deform is reduced, and the plastic substrate cannot be plastically deformed and is easily broken. On the other hand, the present invention is based on a new finding that the elongation at break increases by this heat treatment less than Tg. That is, in the mixed system of metal oxide and polymer as in the present invention, the positive effect of eliminating the stress concentration point by eliminating the gap at the interface between the metal oxide and the polymer rather than the negative effect of inhibiting flow deformation. Seems to be winning.

  In the manufacturing method of this invention, it is preferable to contain 0.1-30 mass% of plasticizers with respect to the mass of a plastic substrate in the plastic film forming process. The brittleness can also be improved by consuming the stress applied to the plastic substrate at the time of fracture to plastic deformation. For this purpose, it is effective to add a plasticizer for causing the molecules of the plastic substrate to flow.

  Examples of the plasticizer include: a) alkyl benzyl phthalate (octyl benzyl phthalate, myristyl benzyl phthalate, etc.), b) dialkyl phthalate (dibutyl phthalate, dihexyl phthalate, dioctyl phthalate, etc.), c) phosphate ester (tricresyl phosphate) ), Trioctyl phosphate, triphenyl phosphate, diphenyl-biphenyl phosphate, etc.) d) fatty acid ester (dibutyl sebacate, acetyl tributyl citrate, etc.), e) polyester series (adipic acid series polyester, sebacic acid series polyester, phthalic acid series) Polyester), f) glycol derivatives (diethylene glycol dibenzoate, dipropylene glycol dibenzoate, triethylene glycol di (2-ethyl) Luhexoate)), glycerin derivatives (glycerol triacetate, glycerol tributyrate, etc.), and g) epoxy derivatives (epoxidized soybean oil, etc.).

  The said plasticizer may be used independently and may be used in combination of 2 or more type. Content of a plasticizer is 0.1-30 mass% with respect to the mass of a plastic base material, Preferably it is 1-25 mass%, More preferably, it is 3-20 mass%.

  Next, film formation of the plastic substrate of the present invention will be described. When the fine particle method is used, any of the following film forming methods may be used, but when the sol-gel method is used, a solution film forming method of a thermoplastic resin or a thermosetting resin is preferable.

(1) Thermoplastic polymer (a) Solution film formation The dispersion polymer solution of metal oxide particles prepared as described above is filtered and defoamed according to a conventional method. This is cast on a mirror-polished support (band or drum) from between slits adjusted to have a predetermined thickness. The sol-gel reaction is advanced while raising the temperature in the above-described plurality of temperature ranges. Such multi-stage temperature increase may be performed all on the support, the initial low-temperature reaction may be performed on the support, and then the film may be peeled off to perform the high-temperature reaction at the later stage. The latter is more preferable.

(B) Melt film formation After the metal oxide fine particles and the thermoplastic resin are sufficiently dried, they are put in a kneading extruder and melted. This is extruded from a T-die and solidified on a cooling drum. At this time, in order to improve the flatness of the film surface, a method of attaching to the cooling drum using static electricity (electrostatic application method) can be used. Thereafter, both ends are trimmed and wound. Further, the film thus obtained may be stretched in at least one of longitudinal and lateral directions. The stretching temperature is preferably higher than the glass transition temperature (Tg).

(2) Thermosetting polymer The prepared solution is filtered and defoamed according to a conventional method. This is cast onto a mirror-polished support (band or drum) from between slits adjusted to have a predetermined thickness. The sol-gel reaction is advanced while raising the temperature in the above-described plurality of temperature ranges. Such multi-stage temperature increase may be performed all on the support, or the initial low-temperature reaction may be peeled off on the support, and the high-temperature reaction in the later stage may be performed. The latter is more preferable. It is more preferable to give a temperature difference between the front and back during this initial reaction.

  The curing reaction of the thermosetting polymer may be carried out at any stage of the above process, but it is preferably carried out after the initial low temperature reaction and later in the high temperature reaction. In the case of the photo-curing type, it is achieved by bringing an ultraviolet lamp into these zones. The thermosetting reaction is preferably cured using the heat of these late drying zones.

  The method for producing a plastic substrate of the present invention can overcome the decrease in elongation at break due to the addition of a metal oxide by performing a) heat treatment at Tg or higher, b) heat treatment at less than Tg, and c) addition of a plasticizer. it can. The above-mentioned a) to c) may be carried out alone, but exhibiting a synergistic effect that was not expected by carrying out them in combination, is more effective. Further, this effect is remarkable when a thermosetting polymer is used as the polymer. A thermosetting polymer has a characteristic that heat resistance is likely to be higher than that of a thermoplastic polymer, but has a small elongation at break and brittleness. For this reason, although it becomes easy to become more brittle by mixing with a metal oxide, this can be prevented by implementing this invention, and the plastic substrate excellent in both heat resistance and brittleness can be provided.

[Conductive plastic substrate of the present invention]
<Conductive layer>
The conductive plastic substrate of the present invention has a conductive layer on at least one surface of the plastic substrate. As the conductive layer, a known metal film, metal oxide film, or the like can be used. In particular, from the viewpoint of transparency, conductivity, and mechanical properties, a metal oxide film (metal oxide layer) formed in a vacuum is conductive. It is preferable to use it as a layer. Metal oxide films are, for example, indium oxide, cadmium oxide and tin oxide to which tin, tellurium, cadmium, molybdenum, tungsten, fluorine, zinc, germanium and the like are added as impurities, zinc oxide and titanium oxide to which aluminum is added as impurities The film | membrane containing is mentioned. Among them, an indium oxide thin film mainly composed of tin oxide and containing 2 to 15% by mass of zinc oxide is excellent in transparency and conductivity, and is preferably used.

  The thickness of the conductive layer is preferably 20 to 500 nm, and more preferably 30 to 300 nm. If it is 20 nm or more, sufficient conductivity can be obtained, and the upper limit is not particularly limited, but is preferably 500 nm or less.

  The electrical resistance of the surface of the conductive layer measured at 25 ° C. and 60% RH is 1 to 500 Ω / sq, preferably 1 to 200 Ω / sq, more preferably 1 to 100 Ω / sq, and most preferably. Is 3-60 Ω / sq. When the surface resistance is in the range of 1 to 500 Ω / sq, for example, in the case of a liquid crystal display element, a display defect of the liquid crystal display element does not occur for a long time, and a highly reliable liquid crystal display element can be provided.

  The surface resistance is obtained as the surface electrical resistance value using a predetermined device (for example, KEITHLEY's 8009 RESISTIVITY TEST FIXTURE and KEITHLEY's 6517A type) after conditioning in an environment of 25 ° C. and 60% RH, for example. be able to.

  In consideration of application to a transparent conductive substrate, the light transmittance of the conductive layer is 80% or more, more preferably 83% or more, and still more preferably 85% or more. A light transmittance of 80% or more is preferable because the problem of reduced visibility does not occur.

  The method for forming the conductive layer is not particularly limited. For example, the conductive layer is formed by a vapor deposition method in which a material is deposited from a gas phase such as a sputtering method, a vacuum evaporation method, an ion plating method, or a plasma CVD method. be able to. Especially, it is preferable to produce by sputtering method from a viewpoint that the outstanding electroconductivity and transparency are obtained.

  A preferable degree of vacuum of the sputtering method, vacuum deposition method, ion plating method, and plasma CVD method is 1.33 mPa to 6.65 Pa (0.01 to 50 mTorr), more preferably 6.65 mPa to 1.33 Pa (0.05). -10 mTorr). In addition, it is preferable to apply a surface treatment to a plastic substrate such as plasma treatment (reverse sputtering) or corona treatment before providing the conductive layer. Further, the temperature may be raised to 50 to 200 ° C. while the conductive layer is provided.

<Gas barrier layer>
In order to suppress the gas permeability of the plastic substrate, it is preferable to provide a gas barrier layer in the conductive plastic substrate of the present invention. Examples of the gas barrier layer include metal oxides mainly composed of one or more metals selected from the group consisting of silicon, aluminum, magnesium, zinc, zirconium, titanium, yttrium, and tantalum, silicon, aluminum, and boron. Or a mixture thereof. Among them, a metal mainly composed of silicon oxide having a ratio of the number of oxygen atoms to the number of silicon atoms of 1.5 to 2.0 from the viewpoint of gas barrier properties, transparency, surface smoothness, flexibility, film stress, cost, etc. It is preferable to use an oxide.

  The thickness of the gas barrier layer is preferably 10 to 300 nm, and more preferably 30 to 200 nm. If the thickness of the gas barrier layer is 10 nm or more, sufficient gas barrier performance is obtained, and if it is 300 nm or less, transparency is also obtained, which is preferable. The gas barrier layer may be provided on either the same side or the opposite side of the conductive layer, but is preferably provided on the opposite side of the conductive layer.

  The method for creating the gas barrier layer is not particularly limited. For example, vapor deposition that forms a film by depositing a material in a gas phase such as sputtering, vacuum deposition, ion plating, and plasma CVD. It can be produced by the method. Among these, from the viewpoint of obtaining excellent gas barrier properties, it is preferable to produce a gas barrier layer by a sputtering method.

  The preferable vacuum degree of said sputtering method, vacuum evaporation method, ion plating method, and plasma CVD method is 1.33 mPa-6.65 Pa (0.01-50 mTorr), More preferably, 6.65 mPa-1.33 Pa ( 0.05 to 10 mTorr). Moreover, it is preferable to add a surface treatment to the base film like plasma treatment (reverse sputtering) or corona treatment before providing the gas barrier layer. Moreover, you may heat up to 50-200 degreeC during providing the transparent conductive layer.

The gas barrier properties of the conductive plastic substrate having a gas barrier layer, the water vapor transmission rate measured at 40 ° C. 90% RH is 0.01~5g / m ² · day, is 0.03~3g / m ² · day It is preferably 0.05 to ² g / m ² · day. Further, the oxygen permeability was measured at 40 ° C. 90% RH, a 0.01~1ml / m ² · day, is preferably 0.01~0.7ml / m ² · day, 0.01~ More preferably, it is 0.5 ml / m ² · day.

[Conductive polarizing plate, conductive λ / 4 plate and circular polarizing plate]
<Conductive polarizing plate>
In the conductive polarizing plate of the present invention, a polarizing film having an absorption axis inclined by 20 to 70 ° with respect to the longitudinal direction is preferably laminated on the conductive plastic substrate. The absorption axis in the polarizing film is inclined 20 to 70 °, preferably 30 to 60 °, more preferably 40 to 50 ° with respect to the longitudinal direction. Usually, a retardation plate having an absorption axis in a direction (0 °) along the longitudinal direction is used. However, in the conductive polarizing plate of the present invention, one having an inclined absorption axis as described above is used. This is preferable because a wide viewing angle can be easily obtained. As such a polarizing film, for example, those described in JP-A-2002-865554 can be preferably used.

<Conductive λ / 4 plate>
The conductive λ / 4 plate of the present invention is preferably formed by laminating a λ / 4 plate made of an optically anisotropic layer containing a liquid crystalline compound on the conductive plastic substrate or the conductive polarizing plate. The λ / 4 plate used in the conductive λ / 4 plate of the present invention is composed of an optically anisotropic layer formed of a liquid crystalline compound. It is preferable that at least two optically anisotropic layers are laminated. Of these layers, the retardation (Re) value at 550 nm of one layer is preferably 240 to 300 nm, and the retardation (Re) value at 550 nm of the other layer is preferably 80 to 170 nm.

  In addition to the above, the λ / 4 plate is known to exhibit anisotropy by stretching a film and to achieve λ / 4 characteristics (for example, JP 2002-48919 A, JP H 10-90521). However, it is preferable to use in combination with the λ / 4 plate formed of the optically anisotropic layer as in the present invention, because a wider viewing angle can be obtained than to use in combination with the conventional λ / 4 plate. .

  The λ / 4 plate composed of the optically anisotropic layer is prepared as follows.

(Alignment film)
An alignment film is used to align the liquid crystalline compound of the λ / 4 plate. As the alignment film, an alignment film that generates an alignment function by rubbing treatment of an organic compound (preferably polymer) layer is used. The rubbing treatment is a treatment that can change the tilt angle of the liquid crystalline compound with respect to the film plane by rubbing the surface of the organic compound (polymer) layer several times in a certain direction with paper or cloth. Examples of the polymer that is preferably used during the rubbing treatment include polyvinyl alcohol, polyimide derivatives, and nylon. The thickness of the alignment film is preferably 0.01 to 5 μm.

  Furthermore, it is preferable to have a polymerizable group in the alignment film for the purpose of improving the adhesion between the liquid crystalline compound layer and the transparent support. As such an alignment film, for example, an alignment film described in JP-A-9-152509 can be used.

  Examples of the polymer used in the alignment film include modified polyvinyl alcohol having a hydrocarbon group having 1 to 9 carbon atoms. A preferred modified polyvinyl alcohol is represented by the following formula [PX].

  In the formula, VAl is a vinyl alcohol repeating unit, HyD is a repeating unit having a hydrocarbon group having 1 to 9 carbon atoms, and VAc is a vinyl acetate repeating unit. In the formula [PX], x is 20 to 95% by mass, preferably 25 to 90% by mass, y is 2 to 98% by mass, preferably 10 to 80% by mass, and z is 0 to 30% by mass. The amount is preferably 2 to 20% by mass.

  The hydrocarbon group is an aliphatic group, an aromatic group or a combination thereof. The aliphatic group may be cyclic, branched or linear. The aliphatic group is preferably an alkyl group (may be a cycloalkyl group) or an alkenyl group (may be a cycloalkenyl group). The hydrocarbon group may have a substituent. The hydrocarbon group has 1 to 9 carbon atoms, and preferably 1 to 8 carbon atoms. Preferred embodiments of the repeating unit (HyD) having a hydrocarbon group are represented by the following formulas (HyD-I) and (HyD-II).

式中、Ｌ¹は、−Ｏ−、−ＣＯ−、−ＳＯ₂ −、−ＮＨ−、アルキレン基、アリーレン基及びそれらの組み合わせから選ばれる二価の連結基であり、Ｌ² は、単結合又は−Ｏ−、−ＣＯ−、−ＳＯ₂ −、−ＮＨ−、アルキレン基、アリーレン基及びそれらの組み合わせから選ばれる二価の連結基であり、Ｒ¹及びＲ²は、それぞれ炭素原子数１〜９の炭化水素基である。上記の組み合わせにより形成される二価の連結基（Ｌ¹、Ｌ²）の例を、以下に示す。

In the formula, L ¹ is a divalent linking group selected from —O—, —CO—, —SO ₂ —, —NH—, an alkylene group, an arylene group, and combinations thereof, and L ² is a single bond Or a divalent linking group selected from —O—, —CO—, —SO ₂ —, —NH—, an alkylene group, an arylene group, and combinations thereof, and R ¹ and R ² each have 1 carbon atom. ˜9 hydrocarbon groups. Examples of divalent linking groups (L ¹ , L ² ) formed by the above combinations are shown below.

L1: -O-CO-
L2: -O-CO-alkylene group -O-
L3: -O-CO-alkylene group -CO-NH-
L4: -O-CO- alkylene group -NH-SO ₂ - arylene group -O-
L5: -Arylene group -NH-CO-
L6: -Arylene group -CO-O-
L7: -Arylene group -CO-NH-
L8: -Arylene group -O-
L9: -O-CO-NH-arylene group -NH-CO-

  Specific examples of the repeating unit (HyD) having a hydrocarbon group having 1 to 9 carbon atoms are shown below.

  The degree of polymerization of the modified polyvinyl alcohol preferably used in the present invention is preferably 200 to 5,000, more preferably 300 to 3,000. The molecular weight of the polymer is preferably 9,000 to 200,000, and more preferably 13,000 to 130,000. Two or more kinds of polymers may be used in combination. Specific examples of preferable modified polyvinyl alcohol are shown below.

_{PX-1 :-( VAl) 21 -} (HyD-13) 77 - (VAc) 2 -
_{PX-2 :-( VAl) 14 -} (HyD-13) 84 - (VAc) 2 -
_{PX-3 :-( VAl) 21 -} (HyD-16) 77 - (VAc) 2 -
_{PX-4 :-( VAl) 34 -} (HyD-15) 64 - (VAc) 2 -
_{PX-5 :-( VAl) 29 -} (HyD-12) 69 - (VAc) 2 -
_{PX-6 :-( VAl) 46 -} (HyD-14) 52 - (VAc) 2 -
_{PX-7 :-( VAl) 21 -} (HyD-2) 77 - (VAc) 2 -
_{PX-8 :-( VAl) 17 -} (HyD-8) 81 - (VAc) 2 -
_{PX-9 :-( VAl) 21 -} (HyD-13) 77 - (VAc) 2 -
_{PX-10 :-( VAl) 46 -} (HyD-9) 52 - (VAc) 2 -

  The addition amount of the modified polyvinyl alcohol is preferably 0.05 to 10% by mass, and more preferably 0.1 to 5% by mass with respect to the mass of the liquid crystalline compound to which the modified polyvinyl alcohol is added.

  The modified polyvinyl alcohol may be used in combination with a condensing agent. As the condensing agent, a compound having an isocyanate group or a formyl group at the terminal is preferable. Specifically, the following binders can be used.

  Poly (1,4-butanediol) isophorone diisocyanate terminated; poly (1,4-butanediol) tolylene 2,4-diisocyanate terminated; poly (ethylene adipate) tolylene 2,4-diisocyanate terminated; poly (propylene glycol) ) Tolylene 2,4-diisocyanate terminated; 1,6-diisocyanate hexane; 1,8-diisocyanate octane; 1,12-diisocyanate dodecane; isophorone diisocyanate; glyoxal

  Next, the rubbing process will be described. The rubbing treatment can be performed at a predetermined arbitrary angle with respect to the MD direction (slow axis direction) of the conductive plastic substrate serving as the support. The angle of the rubbing direction with respect to the MD direction is preferably rubbed in the same or oblique direction with respect to the MD direction. The angle in the oblique direction is preferably in the range of −45 ° to + 45 °.

  The rubbing treatment can be performed by any method. For example, a rubbing roll is disposed at an arbitrary angle with respect to the MD direction of the substrate on a stage that conveys a long conductive plastic substrate in the MD direction. The substrate surface is rubbed by rotating the rubbing roll while transporting the substrate in the MD direction. The angle formed by the rubbing roll and the moving direction of the stage is a mechanism that can be freely adjusted, and an appropriate rubbing cloth material is stuck on the surface of the rubbing roll.

(Optically anisotropic layer formed of liquid crystalline compound)
The optically anisotropic layer composed of two or more liquid crystalline compounds preferably uses a rod-like liquid crystalline compound or a discotic liquid crystalline compound as the liquid crystalline compound, and a rod-like liquid crystalline compound or discotic liquid crystal having a polymerizable group. It is more preferable to use a functional compound. The liquid crystalline compound is preferably substantially uniformly aligned, and most preferably the liquid crystalline molecules are fixed by a polymerization reaction in a substantially uniformly aligned state.

  Examples of rod-like liquid crystalline compounds include azomethines, azoxys, cyanobiphenyls, cyanophenyl esters, benzoic acid esters, cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexanes, cyano-substituted phenylpyrimidines, alkoxy-substituted phenylpyrimidines. , Phenyldioxanes, tolanes and alkenylcyclohexylbenzonitriles are preferably used. In addition to the above low-molecular liquid crystalline molecules, high-molecular liquid crystalline molecules can also be used. The rod-like liquid crystalline compound having a low molecular polymerizable group that is particularly preferably used is a rod-like liquid crystalline compound of the following formula [IV].

  In the formula [IV], Q1 and Q2 are independent polymerizable groups, M1 and M4 are independent divalent linking groups, and M2 and M3 are independent single bonds or divalent linking groups, respectively. Cy1, Cy2 and Cy3 are divalent cyclic groups, and n is 0, 1 or 2.

In the formula [IV], the polymerizable groups of Q1 and Q2 are preferably functional groups capable of addition polymerization (including ring-opening polymerization) reaction or condensation polymerization reaction. In Formula [IV], M1 and M4 are each independently —O—, —S—, —CO—, —NR ³ — (wherein R ³ is an alkyl group having 1 to 7 carbon atoms or a hydrogen atom. And a divalent linking group selected from the group consisting of a divalent chain group, a divalent cyclic group, and combinations thereof.

  Examples of the divalent linking group comprising the above combination are shown below. Here, the left side is coupled to Q (Q1 or Q2), and the right side is coupled to Cy (Cy1 or Cy3).

M-1: —CO—O—divalent chain group —O—
M-2: -CO-O-divalent chain group -O-CO-
M-3: -CO-O-divalent chain group -O-CO-O-
M-4: -CO-O-divalent chain group -O-divalent cyclic group-
M-5: -CO-O-divalent chain group -O-divalent cyclic group -CO-O-
M-6: -CO-O-divalent chain group -O-divalent cyclic group -O-CO-
M-7: -CO-O-divalent chain group-O-divalent cyclic group-divalent chain group-
M-8: -CO-O-divalent chain group-O-divalent cyclic group-divalent chain group-CO-O-
M-9: -CO-O-divalent chain group-O-divalent cyclic group-divalent chain group-O-CO-
M-10: —CO—O—divalent chain group—O—CO—divalent cyclic group—
M-11: -CO-O-divalent chain group -O-CO-divalent cyclic group -CO-O-
M-12: -CO-O-divalent chain group -O-CO-divalent cyclic group -O-CO-
M-13: —CO—O—Divalent chain group—O—CO—Divalent cyclic group—Divalent chain group—
M-14: -CO-O-divalent chain group-O-CO-divalent cyclic group-divalent chain group-CO-O-
M-15: -CO-O-divalent chain group-O-CO-divalent cyclic group-divalent chain group-O-CO-
M-16: —CO—O—divalent chain group—O—CO—O—divalent cyclic group—
M-17: -CO-O-divalent chain group -O-CO-O-divalent cyclic group -CO-O-
M-18: -CO-O-divalent chain group -O-CO-O-divalent cyclic group -O-CO-
M-19: —CO—O—Divalent chain group—O—CO—O—Divalent cyclic group—Divalent chain group—
M-20: -CO-O-divalent chain group -O-CO-O-divalent cyclic group -divalent chain group -CO-O-
M-21: -CO-O-divalent chain group-O-CO-O-divalent cyclic group-divalent chain group-O-CO-

  The divalent chain group is selected from an alkylene group, a substituted alkylene group, an alkenylene group, a substituted alkenylene group, an alkynylene group, and a substituted alkynylene group, and selected from an alkylene group, a substituted alkylene group, an alkenylene group, and a substituted alkenylene group. One type is preferable, and an alkylene group or an alkenylene group is more preferable.

  The alkylene group may have a branch. The alkylene group preferably has 1 to 12 carbon atoms, more preferably 2 to 10 carbon atoms, and most preferably 2 to 8 carbon atoms. The alkylene part of the substituted alkylene group is the same as the above alkylene group. Examples of the substituent include a halogen atom.

  The alkenylene group may have a branch. The alkenylene group preferably has 2 to 12 carbon atoms, more preferably 2 to 10 carbon atoms, and most preferably 2 to 8 carbon atoms. The alkylene part of the substituted alkylene group is the same as the alkylene group. Examples of the substituent include a halogen atom.

  The alkynylene group may have a branch. The alkynylene group preferably has 2 to 12 carbon atoms, more preferably 2 to 10 carbon atoms, and most preferably 2 to 8 carbon atoms. The alkynylene part of the substituted alkynylene group is the same as the above alkynylene group. Examples of the substituent include a halogen atom.

  Specific examples of the divalent chain group include ethylene, trimethylene, propylene, butamethylene, 1-methyl-butamethylene, pentamethylene, hexamethylene, octamethylene, 2-butenylene, 2-butynylene and the like.

  The definitions and specific examples of the divalent cyclic group are the same as the definitions and specific examples of Cy1, Cy2 and Cy3 described later.

In the formula [IV], R ³ is preferably an alkyl group having 1 to 4 carbon atoms or a hydrogen atom, more preferably a methyl group, an ethyl group or a hydrogen atom, and most preferably a hydrogen atom. preferable.

In formula [IV], M2 or M3 each independently represents a single bond or a divalent linking group. M 2 and M 3 are each independently a divalent group selected from the group consisting of —O—, —S—, —CO—, —NR ⁴ —, a divalent chain group, a divalent cyclic group, and combinations thereof. Are preferably a linking group or a single bond.

R ⁴ is an alkyl group having 1 to 7 carbon atoms or a hydrogen atom, preferably an alkyl group having 1 to 4 carbon atoms or a hydrogen atom, and preferably a methyl group, an ethyl group, or a hydrogen atom. More preferably, it is a hydrogen atom. The divalent chain group and the divalent cyclic group have the same definitions as M1 and M4.

  In the formula [IV], n is 0, 1 or 2. When n is 2, two M3s may be the same or different, and two Cy2s may be the same or different. n is preferably 1 or 2, and more preferably 1.

  In the formula [IV], Cy1, Cy2 and Cy3 are each independently a divalent cyclic group. The ring contained in the cyclic group is preferably a 5-membered ring, a 6-membered ring or a 7-membered ring, more preferably a 5-membered ring or a 6-membered ring, and most preferably a 6-membered ring. The ring contained in the cyclic group may be a condensed ring. However, it is preferably a monocycle rather than a condensed ring.

The ring included in the cyclic group may be an aromatic ring, an aliphatic ring, or a heterocyclic ring. The aromatic ring includes a benzene ring and a naphthalene ring. The aliphatic ring includes a cyclohexane ring. The heterocycle includes a pyridine ring and a pyrimidine ring.
The cyclic group having a benzene ring is preferably a 1,4-phenylene group. The cyclic group having a naphthalene ring is preferably a naphthalene-1,5-diyl group or a naphthalene-2,6-diyl group. The cyclic group having a cyclohexane ring is preferably a 1,4-cyclohexylene group. The cyclic group having a pyridine ring is preferably a pyridine-2,5-diyl group. The cyclic group having a pyrimidine ring is preferably a pyrimidine-2,5-diyl group.

  The cyclic group may have a substituent. Examples of the substituent include a halogen atom, a cyano group, a nitro group, an alkyl group having 1 to 5 carbon atoms, a halogen-substituted alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, and 1 carbon atom. -5 alkylthio group, acyloxy group having 2 to 6 carbon atoms, alkoxycarbonyl group having 2 to 6 carbon atoms, carbamoyl group, alkyl-substituted carbamoyl group having 2 to 6 carbon atoms, and acylamino having 2 to 6 carbon atoms A group is included.

  Examples of the polymerizable liquid crystal compound represented by the formula [IV] are shown below. However, the liquid crystalline compound used in the present invention is not limited to these.

  In the present invention, a discotic liquid crystalline compound can also be suitably used for the λ / 4 plate. The discotic liquid crystalline compound is preferably aligned substantially perpendicularly to the plastic substrate surface (average inclination angle in the range of 50 to 90 °). The discotic liquid crystalline compounds are described in various literatures (C. Destrade et al., Mol. Crysr. Liq. Cryst., Vol. 71, page 111 (1981); edited by the Chemical Society of Japan, Quarterly Chemical Review, No. 22, Liquid Crystal Chemistry, Chapter 5, Chapter 10, Section 2 (1994); B. Kohne et al., Angew. Chem. Soc. Chem. Comm., Page 1794 (1985); J. Zhang et al., J Am. Chem. Soc., Vol. 116, page 2655 (1994)). The polymerization of the discotic liquid crystalline compound is described in JP-A-8-27284. In order to fix the discotic liquid crystalline compound by polymerization, it is necessary to bond a polymerizable group as a substituent to the discotic core of the discotic liquid crystalline compound. However, when the polymerizable group is directly connected to the disc-shaped core, it becomes difficult to maintain the orientation state in the polymerization reaction. Therefore, a linking group is introduced between the discotic core and the polymerizable group. For this reason, the discotic liquid crystalline compound having a polymerizable group is preferably a compound represented by the following formula [V].

  In formula [V], D is a discotic core, L is a divalent linking group, P is a polymerizable group, and n is an integer of 4 to 12. An example of the disk-shaped core (D) of the formula [V] is shown below. In each of the following examples, LP (or PL) means a combination of a divalent linking group (L) and a polymerizable group (P).

  Examples of the compound forming the discotic core (D) include indene ring, naphthalene ring, azulene ring, fluorene ring, phenanthrene ring, anthracene ring, acenaphthylene ring, biphenylene ring, naphthacene ring, pyrene ring, indole ring, isoindole Ring, benzofuran ring, benzothiophene ring, indolizine ring, benzoxazole ring, benzothiazole ring, benzimidazole ring, benzotriazole ring, purine ring, indazole ring, chromene ring, quinoline ring, isoquinoline ring, quinolidine ring, quinazoline ring, Cinnoline ring, quinoxaline ring, phthalazine ring, pteridine ring, carbazole ring, acridine ring, phenanthridine ring, xanthene ring, phenazine ring, phenothiazine ring, phenoxathiin ring, phenoxazine ring and thianthrene ring Etc., and the like. Among these, naphthalene ring, azulene ring, indole ring, benzoxazole ring, benzothiazole ring, benzimidazole ring, benzotriazole ring and quinoline ring are preferable.

  Preferred specific examples of the discotic core (D), the divalent linking group (L) and the polymerizable group (P) are (D1) to (D15) and L1 to L25 described in JP-A No. 2001-4837, respectively. (P1) to (P18), and the contents described in the publication can be preferably used.

  These liquid crystalline compounds are preferably substantially uniformly aligned, more preferably fixed in a substantially uniformly aligned state, and the liquid crystalline compound is fixed by a polymerization reaction. Most preferably. Among the liquid crystal compounds, in the case of a rod-like liquid crystal compound having a polymerizable group, it is preferably fixed in a substantially horizontal (homogeneous) orientation.

  Here, “substantially horizontal” means that the average angle (average inclination angle) between the major axis direction of the rod-like liquid crystal compound and the surface of the optically anisotropic layer is in the range of 0 to 40 °. The rod-like liquid crystalline compound may be oriented obliquely or may be changed so that the inclination angle gradually changes (hybrid orientation). Even in the case of oblique orientation or hybrid orientation, the average inclination angle is preferably in the range of 0 to 40 °.

  In the case of a discotic liquid crystalline compound having a polymerizable group, it is preferable to substantially align it vertically. Here, “substantially perpendicular” means that the average angle (average inclination angle) between the disc surface of the discotic liquid crystalline compound and the surface of the optically anisotropic layer is in the range of 50 to 90 °. The discotic liquid crystalline compound may be obliquely aligned or may be gradually changed (hybrid alignment). Even in the case of oblique alignment or hybrid alignment, the average inclination angle is preferably in the range of 50 to 90 °.

  The optically anisotropic layer is preferably formed by applying a coating liquid containing a liquid crystalline compound and the following polymerization initiator and other additives on the alignment film. As a solvent used for preparing the coating solution, an organic solvent is preferably used. Examples of the organic solvent include amide (for example, N, N-dimethylformamide), sulfoxide (for example, dimethyl sulfoxide), heterocyclic compound (for example, pyridine), hydrocarbon (for example, benzene, hexane), alkyl halide (for example, chloroform). , Dichloromethane), esters (eg, methyl acetate, butyl acetate), ketones (eg, acetone, methyl ethyl ketone), ethers (eg, tetrahydrofuran, 1,2-dimethoxyethane). As the organic solvent, an alkyl halide or a ketone is preferably used. Two or more organic solvents may be used in combination.

  The coating liquid can be applied by a known method (eg, extrusion coating method, direct gravure coating method, reverse gravure coating method, die coating method).

(Fixation of alignment state of liquid crystalline compounds)
The aligned liquid crystalline compound is preferably fixed while maintaining the alignment state. The immobilization is preferably carried out by a polymerization reaction of a polymerizable group introduced into the liquid crystal compound. The polymerization reaction includes a thermal polymerization reaction using a thermal polymerization initiator and a photopolymerization reaction using a photopolymerization initiator, and is preferably a photopolymerization reaction. As photopolymerization initiators, α-carbonyl compounds (described in the specifications of US Pat. Nos. 2,367,661 and 2,367,670), acyloin ethers (described in US Pat. No. 2,448,828), α-hydrocarbon substituted aromatic acyloin compounds ( US Pat. No. 2,722,512), polynuclear quinone compound (described in US Pat. Nos. 3,046,127 and 2,951,758), a combination of triarylimidazole dimer and p-aminophenyl ketone (described in US Pat. No. 3,549,367) And acridine and phenazine compounds (JP-A-60-105667, described in US Pat. No. 4,239,850) and oxadiazole compounds (described in US Pat. No. 4,212,970).

The addition amount of the photopolymerization initiator is preferably 0.01 to 20% by mass, and more preferably 0.5 to 5% by mass with respect to the mass of the solid content of the coating solution. Light irradiation for the polymerization of the liquid crystalline compound is preferably performed using ultraviolet rays. Irradiation energy is preferably 20~50J / cm ^2, further preferably 100 to 800 mJ / cm ^2. In order to accelerate the photopolymerization reaction, light irradiation may be performed under heating conditions. The thickness of the optically anisotropic layer is preferably 0.1 to 10 μm, and more preferably 0.5 to 5 μm.

(Optical properties of conductive λ / 4 plate)
In the conductive λ / plate of the present invention, the optically anisotropic layer (first optically anisotropic layer) of the λ / 4 plate has a retardation (Re) value measured at a wavelength of 550 nm of 240 to 290 nm. Preferably, it is 250-280 nm. The other optically anisotropic layer (second optically anisotropic layer) preferably has a retardation (Re) value measured at a wavelength of 550 nm of 110 to 145 nm, and more preferably 120 to 140 nm.

  In order to obtain such optical characteristics, the thicknesses of the first and second optically anisotropic layers described above can be arbitrarily determined within a range in which each layer exhibits a desired retardation. For example, when the first and second optically anisotropic layers are formed by horizontally aligning the same rod-like liquid crystalline compound, the thickness of the optically anisotropic layer having a retardation of π is set to the retardation. Is preferably double the thickness of the optical anisotropy of π / 2. Although the preferable range of the thickness of each optically anisotropic layer varies depending on the type of liquid crystal compound used, it is generally 0.1 to 10 μm, more preferably 0.2 to 0.8 μm, More preferably, it is 5-5 micrometers.

[Circularly polarizing plate]
The circularly polarizing plate of the present invention can be produced by laminating a polarizing film and a λ / 4 plate on the plastic substrate or the conductive plastic substrate. In this case, lamination is performed so that the slow axis of the λ / 4 plate and the absorption axis of the polarizing film are 45 °. At this time, as described above, it is formed of a polarizing film having an absorption axis inclined by 20 to 70 °, preferably 30 to 60 °, more preferably 40 to 50 ° with respect to the longitudinal direction, and the liquid crystal compound described above. It is preferable to laminate a λ / 4 plate made of an optically anisotropic layer.

[Liquid crystal display element]
The reflective liquid crystal display device includes, in order from the bottom, a lower substrate, a reflective electrode, a lower alignment film, a liquid crystal layer, an upper alignment film, a transparent electrode, an upper substrate, a λ / 4 plate, and a polarizing film. Among these, the plastic substrate of the present invention can be used as a transparent electrode and an upper substrate. In the case of color display, it is preferable to further provide a color filter layer between the reflective electrode and the lower alignment film, or between the upper alignment film and the transparent electrode. On the other hand, the transmissive liquid crystal display device includes a backlight, a polarizing plate, a λ / 4 plate, a lower transparent electrode, a lower alignment film, a liquid crystal layer, an upper alignment film, an upper transparent electrode, an upper substrate, and a λ / 4 plate in order from the bottom. And a polarizing film. Among these, the plastic substrate of the present invention can be used as an upper transparent electrode and an upper substrate. In the case of color display, it is preferable to further provide a color filter layer between the lower transparent electrode and the lower alignment film, or between the upper alignment film and the transparent electrode.

  The liquid crystal cell is not particularly limited, but more preferably a TN (twisted nematic) type, STN (supplier twisted nematic) type or HAN (hybrid aligned nematic) type, VA (verticaly allignment) type, ECB (electrically controlled birefrigence) type, OCB (Optically Compensatory Bend) type or CPA (Continious Pinwheel Alignment) type is preferable.

[Touch panel]
As a touch panel, what was described in Unexamined-Japanese-Patent No. 5-127822, 2002-48913, etc. can be used, for example.

[Organic EL device]
Examples of the organic EL element include, for example, JP-A-11-233258, JP-A-2000-150172, JP-A-2000-267097, JP-A-2001-135477, JP-A-2001-351781, and JP-A-2001-351781. What was described in 2002-75657 gazette, Unexamined-Japanese-Patent No. 2002-110345, and Unexamined-Japanese-Patent No. 2002-169277 can be used.

  Since the plastic substrate of the present invention has a relatively high elongation at break and a relatively small coefficient of thermal expansion, it is low. Therefore, even when an alignment film is formed or incorporated in an image display element, white point failure occurs. Few. For this reason, the plastic substrate of this invention can be used for various image display elements, such as a touch panel and an organic EL element.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated further more concretely, this invention is not limited to a following example. In the examples, parts and% are based on mass unless otherwise specified. Various measurements in the examples were performed as follows.

[Measurement method]
A. Thermal deformation temperature and thermal expansion coefficient TMA (Thermal Mechanical Analysis) measurement was performed under the following conditions. That is, the dimensional change of the sample accompanying the temperature rise is measured.
Sample width: 3mm
Between chucks: 25.4 mm
Temperature increase rate: 3 ° C / min
Measurement temperature range: 30 ° C to 200 ° C
The thermal deformation temperature and the thermal expansion coefficient were determined by the following method.
(1) Thermal deformation temperature Although elongation occurred as the temperature rose, the amount of elongation increased rapidly from the vicinity of Tg. The intersection of the extrapolated line extending below Tg and the extrapolated line extending above Tg was defined as the heat distortion temperature (° C.).
(2) Coefficient of thermal expansion The coefficient of thermal expansion was determined from the slope of temperature change (ratio to the length between chucks: ppm) and temperature (° C) (ppm / ° C).

B. A sample of elongation at break was cut out using a razor at 1 cm × 20 cm, pulled at 10 ° C. between chucks at a pulling speed of 2 cm / min at 25 ° C. and 60% RH, and obtained from the following formula from the pulling length (Lcm) when broken. .
Elongation at break (%) = 100 × (Lcm / 10 cm)

C. Retardation value (Re)
Using an automatic birefringence meter (KOBRA-21ADH / PR: manufactured by Oji Scientific Instruments), measurement was performed from the direction perpendicular to the sample film surface. This measurement was performed at a wavelength of 550 nm under the same environment after holding the sample in an environment of 25 ° C. and 60% RH for 2 hours.

D. Surface Electric Resistance (1) Initial Surface Electric Resistance After adjusting humidity to 25 ° C. and 60% RH for 3 hours or more, initial electric resistance (R ₀ ) was measured using an 8009 RESISTIVITY TEST FIXTURE made by KEITHLEY and a 6517A type made by KEITHLEY.
(2) Surface electrical resistance after heat treatment The sample was suspended under no tension using an air thermostat and subjected to heat treatment at 175 ° C for 30 minutes. After adjusting the humidity to 25 ° C. and 60% RH for 3 hours or more, the surface electrical resistance (R ₁₇₅ ) was measured in the same manner as in (1).
(3) the rate of change of surface electrical resistance (R ₁₇₅₎ the absolute value of the difference between (R ₀₎ divided by (R _0), and the change rate of the one surface resistivity shown in percentage (%).

E. Water vapor transmission rate (1) Initial water vapor transmission rate Using a Permantran W1A manufactured by MOCON, measurement was performed for 24 hours in an atmosphere of 40 ° C and 90% RH, and the water vapor transmission rate was measured. This was designated as W ₀ .
(2) Water vapor permeability after heat treatment The sample was suspended under no tension using an air thermostat and subjected to heat treatment at 175 ° C for 30 minutes. After adjusting the humidity to 25 ° C. and 60% RH for 3 hours or more, the water vapor transmission rate (W ₁₇₅ ) was measured in the same manner as in (1).
(3) was the rate of change of the water vapor transmission rate and (W ₁₇₅₎ and (W ₀₎ of the absolute value of the difference between (W ₀₎ in the split, the change rate of water vapor transmission rate that shown in percentage (%).

F. Oxygen permeability (1) Initial oxygen permeability Oxygen permeability was measured by using OX-TRAN 10 / 50A, manufactured by MOCON, for 24 hours in an atmosphere of 40 ° C. and 90% RH. This was designated as O ₀ .
(2) Oxygen permeability after heat treatment This sample was suspended under no tension using an air thermostat and subjected to heat treatment at 175 ° C for 30 minutes. After adjusting the humidity to 25 ° C. and 60% RH for 3 hours or more, the oxygen transmission rate (O ₁₇₅ ) was measured in the same manner as (1).
(3) changes of oxygen transmittance (O ₁₇₅₎ and (O ₀₎ of the absolute value of the difference between (O ₀₎ in the split, the change rate of the water vapor transmission rate that shown in percentage (%).

Example 1 Production of Plastic Substrate Preparation of plastic substrate by solution casting method (1) Preparation of thermoplastic resin solution The following polymer was dissolved in methylene chloride so as to have a content of 20% by mass. A silane coupling agent (γ-glycidoxypropyltrimethoxysilane) and a plasticizer (glycerol triacetate) were mixed in the addition amount shown in Table 1 with respect to the mass of the polymer.
a) MPC-1
Polycarbonate copolymer in which bisphenol A (BisA) and 9,9-bis (4-hydroxy-3-methylphenyl) fluorene (BCF) are mixed at BisA / BCF = 1/1 (molar ratio) (Tg: 225 ° C. )
b) MPC-2
Polycarbonate copolymer in which bisphenol A (BisA) and 3,3,5-trimethyl-1,1-di (4-phenol) cyclohexylidene (IP) are mixed at BisA / IP = 2/3 (molar ratio) Tg: 205 ° C.).
c) PES
Sumitomo Bakelite Sumilite FS-1300 (Tg: 220 ° C.).

(2) Preparation of prepolymer solution of thermosetting resin 100 parts by mass of the following prepolymer, 300 parts by mass of 1-methoxy-2-propanol, 2 parts by mass of 1-hydroxycyclohexyl phenyl ketone as an initiator, and a silane coupling agent (KBM-503 manufactured by Shin-Etsu Chemical Co., Ltd.) and a plasticizer (triphenyl phosphate) were mixed in an addition amount described in Table 1 with respect to the mass of the polymer.
a) EpAc
Epoxy acrylate prepolymer having a molecular weight of about 1040 (VR-60, Showa Polymer Co., Ltd.)
b) Ac
Acrylic resin (Acrylic with molecular weight 67,000, acid value 2 (Mitsubishi Rayon Co., Ltd. LR-1065))
c) DCPA
Dimethylol tricyclodecane diacrylate (“Light acrylate DCP-A” manufactured by Kyoeisha Chemical Co., Ltd.)
d) UA
Urethane acrylate (Shin Nakamura Chemical "NK Oligo U-15HA")
e) PhR
Phenoxy resin ("PAPHEN" manufactured by Phenoxy Associates)
f) PI
Polyisocyanate ("Coronate" manufactured by Nippon Polyurethane Industry)
g) DA
Diacrylate monomer (compound described in Example 1 of JP-A-2002-275285)

(3) Preparation of casting dope A metal oxide was added to the preparation of the thermoplastic resin solution and the prepolymer solution of the thermosetting resin. The metal oxide content (the mass ratio of the metal oxide after the sol-gel reaction to the polymer) is shown in Table 1.
(A) Fine particle method Various metal oxide particles having a particle size described in Table 1 were added. The metal oxide particles used in the present invention had a spherical aspect ratio of 5 or less. On the other hand, a plate-like material having an aspect ratio of 15 was also added to form a film by the following method, but in all cases Ra was as large as 20 nm.
(B) Sol-gel method Various metal oxides prepared by the following sol-gel method were added in the amounts shown in Table 1.
a) Silica-based sol-gel solution (Si-based)
After adding 88 parts by mass of acetic acid to a mixed solvent of 1800 parts by mass of 2-propanol, 640 parts by mass of 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 154 parts by mass of 3-aminopropyltrimethoxysilane (ECHETMOS) The parts were mixed.
b) Alumina-based sol-gel solution (Al-based)
Aluminum isopropoxide (manufactured by Wako Pure Chemical Industries, Ltd., solid content 40% by mass) and n-propyl alcohol were mixed, 10 mol / L hydrochloric acid was added dropwise, and N, N-dimethylbenzylamine was added after completion of the addition. Thereafter, a solution of 15 parts by mass of aluminum isopropoxide was obtained.
c) Silica alumina based sol-gel solution (SiAl based)
After dissolving 80% by mass of tetraethoxysilane (TEOS), 10% by mass of aminopropyltriethoxysilane, 5% by mass of glycidylpropyltriethoxysilane and 5% by mass of methylpropylacrylethoxysilane in n-propyl alcohol, 2 mol / L ( 2N) hydrochloric acid was added dropwise.

(4) Film formation The above mixed solution was cast on a stainless steel band by a die coating method. This was subjected to an initial reaction on the band at a temperature of 60 ° C. for 2 minutes. Next, this was peeled off from the band and subjected to the late reaction at a temperature of 150 ° C. for 20 minutes. Thereafter, both ends were trimmed, knurled, and wound on a roll. The thickness of the plastic substrate thus obtained is shown in Table 1. In the present invention, each film was formed with a width of 1.5 m and a length of 3000 m. The residual solvent concentration was 1% by mass or less.

2. Production of plastic substrate by melt film-forming method The following polymer was added with the metal oxide particles, silane coupling agent (vinyl tris (β-methoxyethoxy) silane), and plasticizer (diethylene glycol dibenzoate) listed in Table 1 as the mass of the polymer. On the other hand, after mixing with the addition amount described in Table 1, it was melted at 250 ° C. using a twin-screw kneading extruder. This was cast from a T-die onto a casting drum adjusted to 120 ° C. using an electrostatic application method and solidified.

COC (cycloolefin copolymer): Polynorbornene (Arton manufactured by Jiesal Co., Ltd., Tg: 160 ° C.)
Thereafter, both ends were trimmed, knurled, and wound up. The thickness of the plastic substrate thus obtained is shown in Table 1.

3. Heat treatment for Tg or more The plastic substrate obtained by the above solution film formation and melt film formation was heat-treated while being conveyed to the heat treatment zone under the conditions (tension, temperature, time) described in Table 1.

4). Subsequent to Tg heat treatment Tg or higher heat treatment, the plastic substrate was rolled and heat treated under the conditions (temperature, time) shown in Table 1.

5. Physical property evaluation According to the above-mentioned method, the physical property of the plastic substrate was evaluated after film formation. The results are shown in Table 1.

  In the production method of the present invention, a) addition of plasticizer, b) addition of silane coupling agent, c) heat treatment above Tg, and d) heat treatment below Tg are all low thermal expansion coefficient, large elongation at break. It showed good temperature, high heat distortion temperature, low Ra and low haze. The above a) to d) were combined to obtain better results (plastic substrates # 1, # 6 to 8, and # 11 to 18). These were similarly effective in both the thermosetting polymer and the thermoplastic polymer, but the thermosetting polymer had higher heat resistance, and more favorable results were obtained (Plastic substrates # 11 to 17 etc.) ). The plastic substrates of the present invention all showed high transparency of 85% or more.

[Example 2] Production of conductive plastic substrate Preparation of undercoat layer After performing corona discharge treatment on both sides of the above plastic substrate, the coating liquid of the following formulation was stirred and dissolved at room temperature, and then coated with a bar coater to a thickness of 3 μm (after drying). After heating at 80 ° C. for 10 minutes, ultraviolet rays were irradiated.
Acrylic resin 100 parts by weight (Tg105 ° C, molecular weight 67,000, acid value 2 acrylic
(LR-1065 manufactured by Mitsubishi Rayon Co., Ltd.))
Silane coupling agent 1 part by mass (N-phenyl-γ-aminopropyltrimethoxysilane (KBM-573 manufactured by Shin-Etsu Chemical Co., Ltd.))
400 parts by weight of butyl acetate

2. Preparation of Gas Barrier Layer The following barrier layer was formed in the thickness shown in Table 2 on the undercoat layer on one side of the plastic substrate.
(1) SiO ₂ layer Sputtering was performed at a power of 5 kW in an Ar atmosphere under a vacuum of 665 mPa (5 mTorr) using SiO ₂ as a target by a DC magnetron sputtering method (described as SiO in Table 2).
(2) by SiO _x N _y layer RF magnetron sputtering method, an Si as a target, while introducing O _2, N _2, under a vacuum of 665MPa (5 mTorr), deposited at the output 5 kW, SiO _x N _y film (X = 1, y = 1) was obtained (described as SiON in Table 2).
(3) Al ₂ O ₃ layer Sputtering was performed at a power of 5 kW in an Ar atmosphere under a vacuum of 665 mPa (5 mTorr) using Al ₂ O ₃ as a target by DC magnetron sputtering (described as AlO in Table 2).

3. Preparation of transparent conductive layer (1) ITO layer 665 mPa (5 mTorr) by DC magnetron sputtering method using ITO (In ₂ O ₃ 95 mass%, SnO ₂ 5 mass%) as a target while heating the plastic substrate to 100 ° C. A transparent conductive layer made of an ITO film having the thickness shown in Table 2 at an output of 5 kW under vacuum and in an Ar atmosphere was provided on the undercoat layer on the opposite surface of the gas barrier layer (described as ITO in Table 2).
(2) Indium / Zinc Oxide Layer According to Example 1 of JP-A-6-318406, an oxide film made of In and Zn was formed (described as IZO in Table 2).

4). On the barrier layer, a coating solution having the following formulation was stirred and dissolved at room temperature, then applied to a thickness of 3 μm (after drying) with a bar coater, and heated at 80 ° C. for 10 minutes. After that, ultraviolet rays were irradiated.
Acrylic resin 100 parts by weight (Tg105 ° C, molecular weight 67,000, acid value 2 acrylic
(LR-1065 manufactured by Mitsubishi Rayon Co., Ltd.))
Silane coupling agent 1 part by mass (N-phenyl-γ-aminopropyltrimethoxysilane (KBM-573 manufactured by Shin-Etsu Chemical Co., Ltd.))
400 parts by weight of butyl acetate

5. Evaluation The surface resistance of the conductive plastic substrate obtained as described above was measured by the above method. Furthermore, according to the following method, the water vapor transmission rate and the oxygen transmission rate were measured. Furthermore, soldering distortion was evaluated by the following method. Soldering distortion evaluation is to evaluate durability when exposed to high temperature during soldering. The results are shown in Table 2.

<Soldering distortion>
First, the plastic substrate is cut into 5 cm × 5 cm, and the four corners are held 1 cm at a time and are suspended and fixed in the air. Next, a metal bar having a diameter of 5 mm heated to 200 ° C. is applied to the center of the plastic substrate with a load of 100 g and pressed for 3 minutes. Next, the metal bar pressed surface is placed on a flat table, and the average height at which the four corners are lifted is obtained.

6). Preparation of polyimide alignment film A polyimide alignment film (SE-7992, manufactured by Nissan Chemical Industries, Ltd.) for aligning liquid crystals was formed on the transparent conductive (ITO) layer side of the conductive plastic substrate. Heat treatment was performed at 200 ° C. for 30 minutes, and this was rubbed. The surface resistance, water vapor transmission rate and oxygen transmission rate of the obtained substrate were measured. The results are shown in Table 2.

  From Table 2, when using the plastic substrate of the present invention, when comparing the physical property value immediately after film formation and the physical property value after polyimide orientation, there is almost no increase in surface resistance and gas permeability (water vapor permeability and Almost no increase in oxygen permeability was observed. In addition, in the case of using the plastic substrate of the present invention, the soldering strain is smaller when the substrate made of the thermosetting polymer is smaller than the one made of the thermoplastic polymer even at a high temperature. It turns out that it is excellent in durability.

Example 3 Production of Circular Polarizing Plate Production of Conductive λ / 4 Plate (1) λ / 4 Plate Formed with Optical Anisotropic Layer Application was performed on the gas barrier layer side of the conductive plastic substrate of the present invention by the following procedure (in Table 3, It is described as an optically anisotropic type).
a) Preparation of PVA Alignment Film After saponifying both sides of an 80 μm cellulose triacetate film (Fuji Photo Film Fujitac) with an aqueous NaOH solution, an alignment film coating solution having the following composition was applied to one side of Fujitac and dried at 100 ° C. It was. The thickness of the alignment film was 1 μm. Next, rubbing treatment was performed so that the slow axis direction of the optically anisotropic layer was 30 ° with respect to the longitudinal direction of the transparent support.
4% by mass of the following modified polyvinyl alcohol
72.6% by mass of water
Methanol 23.3 mass%
Glutaraldehyde 0.2% by mass

b) Preparation of optically anisotropic layer A On the alignment film, a coating solution having the following composition is continuously applied using a bar coater, dried, and heated (orientation aging), and further irradiated with ultraviolet rays to optically An anisotropic layer was formed. At this time, the retardation value (Re) shown in Table 2 was obtained by changing the coating thickness. This optically anisotropic layer had a slow axis in the direction of 30 ° with respect to the longitudinal direction of the transparent support.
Coating liquid composition for optically anisotropic layer (A) Rod-like liquid crystalline compound (Exemplary Compound I-2) in the present specification 38.1% by mass
Sensitizer A 0.38% by mass
The following photoinitiator B 1.14 mass%
Exemplary compound (PX-9) in the present specification 0.19% by mass
Glutaraldehyde 0.04% by mass
Methyl ethyl ketone 60.1% by mass

  The optical anisotropy is −60 ° with respect to the slow axis of the optically anisotropic layer (A) prepared above and −30 ° with respect to the longitudinal direction of the optically anisotropic layer (A). A rubbing treatment was performed after the application of the adhesive layer (A).

c) Preparation of optically anisotropic layer (B) On the optically anisotropic layer (A) subjected to the rubbing treatment, a coating solution having the following composition was applied, dried and heated (alignment aging) using a bar coater. Then, the optically anisotropic layer (B) was formed by ultraviolet irradiation. At this time, the retardation value (Re) shown in Table 2 was obtained by changing the coating thickness.

Coating liquid composition for optically anisotropic layer (B) Rod-like liquid crystalline compound of the present invention (Exemplary Compound I-2) 38.4% by mass
Sensitizer A 0.38% by mass
Photopolymerization initiator B 1.15% by mass
Orientation control agent C 0.06% by mass
Methyl ethyl ketone 60.0 mass%

(2) Production of Non-Optically Anisotropic Layer λ / 4 Plate According to Example 1 of Japanese Patent Laid-Open No. 2002-48919, λ / 4 obtained by stretching a polycarbonate film was prepared. Type and description).

2. Preparation of polarizing plate The PVA film was immersed in an aqueous solution of 2.0 g / L of iodine and 4.0 g / L of potassium iodide at 25 ° C. for 240 seconds, and further immersed in an aqueous solution of boric acid 10 g / L at 25 ° C. for 60 seconds. After that, it is introduced into a tenter stretching machine as shown in FIG. 1 and stretched 5.3 times, the tenter is bent as shown in FIG. 1 with respect to the stretching direction, and the transition width is kept constant and contracted. However, it was dried in an atmosphere at 80 ° C. and then detached from the tenter. The moisture content of the PVA film before starting stretching was 31%, and the moisture content after drying was 1.5%. The difference in transport speed between the left and right tenter clips was less than 0.05%, and the angle between the center line of the introduced film and the center line of the film sent to the next process was 46 °.

  Here, | L1-L2 | is 0.7 m, W is 0.7 m, and | L1-L2 | = W. The substantial stretching direction Ax-Cx at the tenter outlet was inclined by 45 ° with respect to the center line 12 of the film sent to the next process. Wrinkles and film deformation at the tenter exit were not observed. Further, the tenter clip having a difference in the conveying speed was created on the left and right sides to create an inclined absorption axis as shown in Table 3. A polarizing plate having an effective width of 650 mm by being bonded to a saponified Fuji Photo Film Co., Ltd. Fujitac, using a 3% aqueous solution of PVA (manufactured by Kuraray Co., Ltd., PVA-117H) as an adhesive, and drying at 80 ° C. Got.

  As a comparative example, a longitudinal stretcher was used to stretch in the longitudinal direction (absorption axis angle = 0 degree).

  Next, the λ / 4 plate is bonded to one side of the iodine-based polarizing film prepared above so that the absorption axis of the polarizing plate and the slow axis of the λ / 4 plate are 45 °, and the circularly polarizing plate Was prepared.

Example 4 Production of Liquid Crystal Display Device Fabrication of TN type liquid crystal display device An aluminum reflective electrode with fine irregularities formed on the gas barrier layer side of a conductive plastic substrate with a polyimide alignment film (plastic substrate laminated with a gas barrier layer and a transparent conductive layer) (Lower electrode). After the circularly polarizing plate adjusted by the above-described method and the lower electrode are cut into a size of 15 inches, the polyimide alignment films of both are 1.7 μm so that the rubbing directions intersect at an angle of 110 °. The two substrates face each other through the spacer. Liquid crystal (MLC-6252, manufactured by Merck) was injected into the gap between these substrates to form a liquid crystal layer. In this way, a TN liquid crystal cell having a twist angle of 70 ° and a Δnd value of 269 nm was produced. This was indicated as black on the entire surface, and the number of white spots appearing on the screen was visually measured and shown in Table 3.

2. Fabrication of STN type liquid crystal display device An aluminum reflective electrode with fine irregularities formed on the gas barrier layer side of a conductive plastic substrate with a polyimide alignment film (plastic substrate laminated with a gas barrier layer and a transparent conductive layer) (Lower electrode). After the circularly polarizing plate adjusted by the above method and the lower electrode are cut to a size of 15 inches, a 6 μm spacer is formed so that the rubbing directions intersect at an angle of 60 ° between the two polyimide alignment films. The two substrates were faced through each other. Liquid crystal (ZLI-2777, manufactured by Merck & Co., Inc.) was injected into the gap between these substrates to form a liquid crystal layer. Thus, an STN type liquid crystal cell having a twist angle of 240 ° and a Δnd value of 791 nm was produced. This was indicated as black on the entire surface, and the number of white spots appearing on the screen was visually measured and shown in Table 3.

  In the case of using the plastic substrate of the present invention, the number of white spot failures due to chips during cutting was small, and a good image was obtained. On the other hand, in the case using the comparative example, many white spot failures occurred. Further, in the case of using the plastic substrate of the present invention, by combining with a polarizing plate having an absorption axis inclined by 20 to 70 °, a λ / 4 plate composed of an optically anisotropic layer formed of a liquid crystalline compound, A wider viewing angle was obtained (the viewing angle was obtained by inclining the line of sight from the vertical and visually observing the angle at which the color of the image was reversed).

[Example 5] Production of touch panel A touch panel was produced according to the description in JP-A-5-127822 and JP-A-2002-48913. Those using the plastic substrate of the present invention showed good performance, and the white spot failure hardly occurred.

[Example 6] Preparation of organic EL element According to Japanese Patent Application Laid-Open No. 2000-267097, an optical organic EL element is protected in order from the observer side (with an antireflection functional layer on the outermost surface) / the above circular polarizing plate (of the present invention A conductive plastic substrate (with a conductive layer and a gas barrier layer laminated on a plastic substrate) ITO layer on the organic EL side) / organic EL element / reflection electrode was prepared.

  Those using the plastic substrate of the present invention showed good performance, and the white spot failure hardly occurred.

It is a schematic plan view which shows an example of the manufacturing method of the plastic substrate of this invention which diagonally stretches a polymer film.

Explanation of symbols

(A) Step of introducing film (b) Step of stretching film (c) Step of transporting stretched film to the next step A1 Position of biting into film holding means and starting position of film stretching (substantially holding start point: right)
B1 Biting position of film holding means (left)
C1 Film stretch starting position (substantially holding start point: left)
Cx film release position and film stretching end point reference position (substantially holding release point: left)
Ay Film drawing end point reference position (substantially holding release point: right)
| L1-L2 | Stroke difference between left and right film holding means W Substantially width at the end of film stretching process θ Angle formed by stretching direction and film traveling direction 11 Center line 12 of introduction side film Center line 13 of film sent to next process Trajectory of film holding means (left)
14 Trajectory of film holding means (right)
15 Introducing film 16 Films 17 and 17 'sent to the next process Left and right film holding start (biting) points 18 and 18' Release points from the left and right film holding means

Claims (9)

A plastic containing a metal oxide in a polymer, having a coefficient of thermal expansion of 1 to 50 ppm / ° C, an elongation at break of 3 to 50%, and a heat distortion temperature of 200 to 400 ° C. substrate. The plastic substrate according to claim 1, wherein the light transmittance is 75% or more and / or the retardation (Re) is 50 nm or less. A conductive plastic substrate comprising a conductive layer having a surface resistance of 1 to 100 Ω / sq on at least one surface of the plastic substrate according to claim 1. The conductive plastic substrate according to claim 3, wherein the conductive plastic substrate has at least one 30 to 300 nm metal oxide layer formed in a vacuum. A conductive polarizing plate comprising a polarizing film having an absorption axis inclined by 20 to 70 ° with respect to the longitudinal direction on the conductive plastic substrate according to claim 3 or 4. A λ / 4 plate comprising an optically anisotropic layer formed of a liquid crystalline compound on the conductive plastic substrate according to any one of claims 3 to 5 or the conductive polarizing plate according to claim 5. A conductive λ / 4 plate characterized by being laminated. A polarizing film having an absorption axis inclined by 20 to 70 ° with respect to the longitudinal direction and a liquid crystalline compound formed on the plastic substrate according to claim 1 or 2 or the conductive plastic substrate according to claim 3 or 4. A circularly polarizing plate comprising a laminated λ / 4 plate made of an optically anisotropic layer. A method for producing a plastic substrate containing a metal oxide in a polymer, wherein after the substrate is formed, the substrate is heat-treated at a temperature equal to or higher than Tg of the polymer while applying a tension of 1 to 20 kg / m to the substrate. A method for producing the plastic substrate, comprising: The method for producing a plastic substrate according to claim 8, wherein the substrate obtained by heat treatment at a temperature of Tg or higher is heat-treated at a temperature of 50 ° C or higher and lower than Tg of the polymer for 3 to 200 hours.

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