WO2006129656A1

WO2006129656A1 - Multilayer optical compensation film

Info

Publication number: WO2006129656A1
Application number: PCT/JP2006/310766
Authority: WO
Inventors: Masakazu Nakata; Yoshito Takeuchi
Original assignee: Sekisui Chemical Co., Ltd.
Priority date: 2005-05-31
Filing date: 2006-05-30
Publication date: 2006-12-07
Also published as: TW200706573A; JP2006337565A

Abstract

Disclosed is a multilayer optical compensation film used for improving the image quality of a liquid crystal display. Specifically disclosed is a multilayer optical compensation film composed of a cycloolefin resin film and a homeotropically aligned liquid crystal layer arranged on the cycloolefin resin film. In this multilayer optical compensation film, a surface of the cycloolefin resin film in contact with the homeotropically aligned liquid crystal layer is subjected to an atmospheric pressure plasma treatment using an inert gas having an oxygen concentration of not more than 15% by volume.

Description

Specification

Laminated optical compensation film

Technical field

The present invention relates to a laminated optical compensation film used for improving image quality of a liquid crystal display device.

Background art

[0002] Liquid crystal display devices are used in notebook personal computers, personal computer monitors, and the like, but in recent years, they have also been used for large television applications, and the demand is rapidly increasing.

Liquid crystal display devices used in such applications are required to be viewed well from a wider range, and the VA method and IPS method, which have improved the viewing angle dependency of the conventional TN method, are often used. Has been. However, with these methods, although the viewing angle characteristics in the vertical and horizontal directions on the image display surface are improved, for example, when viewed from an oblique direction, contrast and color reproducibility are insufficient, and further improvements are made. Is required.

[0003] Such a decrease in viewing angle from an oblique direction is considered to be caused by viewing angle characteristics of a polarizing plate used in a liquid crystal display device. As a method for improving this, for example, Patent Document 1 discloses the use of an optical compensation film having an Nz coefficient of 0.5.

Conventionally, as such an optical compensation film, as disclosed in Patent Document 2, a shrinkable film is applied to a resin film to be stretched so that the shrinking direction is orthogonal to the stretching direction. Since it is manufactured by the method of heating and stretching after pasting, it is difficult to manufacture a large optical compensation film for use in large liquid crystal display devices, which have a low yield in the width direction of the film and are in great demand in recent years. It has become.

In recent years, as described in Patent Document 3, for example, a liquid crystal layer in which a vertically aligned liquid crystal layer is laminated on a uniaxially or biaxially stretched film layer as described in Patent Document 3 has been dealt with. A stacked optical compensation film has been proposed.

[0006] As a material for the film layer of the liquid crystal laminated optical compensation film, a polycarbonate or a triacetyl cellulose film is used. However, in a liquid crystal display device manufactured using an optical compensation film having such a film layer, the film layer of the optical compensation film is heated by the heat generated by the backlight during use, and light is emitted by the generated internal stress. There was a problem called display loss that caused display defects.

[0007] To deal with such problems, in recent years, a cycloolefin-based resin excellent in heat resistance and low photoelasticity is being used as a material for a film layer. Applying a liquid crystal solution on a cycloolefin-based resin film to form a liquid crystal layer causes repelling, which is difficult to apply, and the cycloolefin-based resin film and the liquid crystal layer are adhesive. There was a problem of being bad.

Patent Document 1: Japanese Patent Laid-Open No. 4-305602

Patent Document 2: JP-A-5-157911

Patent Document 3: Japanese Unexamined Patent Publication No. 2003-149441

Disclosure of the invention

Problems to be solved by the invention

An object of the present invention is to provide a laminated optical compensation film used for improving the image quality of a liquid crystal display device in view of the above situation.

Means for solving the problem

[0009] The present invention is a laminated optical compensation film comprising a cycloolefin-based resin film and a vertically-aligned liquid crystal layer laminated on the cycloolefin-based resin film, A laminated optical compensation film in which the surface on the side in contact with the vertical alignment liquid crystal layer is subjected to atmospheric pressure plasma treatment with an inert gas having an oxygen concentration of 15% by volume or less.

The present invention is described in detail below.

[0010] As a result of intensive studies, the inventors of the present invention applied the atmospheric pressure plasma treatment under specific conditions to the surface of the cycloolefin-based resin film, and thereby the coating properties of the liquid crystal solution and the resulting liquid crystal layer and It has been found that an extremely high performance optical compensation film can be obtained by laminating a vertical alignment liquid crystal layer as a liquid crystal layer, and the present invention has been completed. . [0011] The laminated optical compensation film of the present invention comprises a cycloolefin-based resin film and a vertically aligned liquid crystal layer laminated on the cycloolefin-based resin film.

[0012] The cycloolefin-based resin film is a film in which a cycloolefin-based resin is formed.

The cycloolefin-based resin is not particularly limited, and examples thereof include norbornene-based resin and dicyclopentagen-based resin. Among them, those having no unsaturated bond or having an unsaturated bond hydrogenated are preferably used. For example, a ring-opening (co) polymer of one or more norbornene monomers is used. Hydrogenated products, addition (co) polymers of one or more norbornene monomers, addition copolymers of norbornene monomers and olefin monomers (ethylene, a-olefin, etc.), norbornene monomers Examples include addition copolymers with cycloolefin monomers (cyclopentene, cyclootaten, 5, 6-dihydrocyclopentagen, etc.), and modified products thereof. Specifically, ZEONEX, ZEONOR (manufactured by Nippon Zeon) ARTON (manufactured by JSR), TOPAS (manufactured by Chicona), APEL (manufactured by Mitsui Chemicals), and the like.

[0013] The film forming method is not particularly limited, and, specifically, a conventionally known film forming method may be used. For example, a cycloolefin-based resin is supplied to an extruder and melted and kneaded. Mold force attached to the tip of the extruder Method of forming a long cycloolefin-based resin film by extruding it into a film (melt extrusion method), a solution obtained by dissolving a cycloolefin-based resin in an organic solvent Examples thereof include a method of evaporating the organic solvent after casting on a drum or band to form a long cycloolefin-based resin film (solution casting method).

If the thickness of the cycloolefin-based resin film is 80 m or more, it may be difficult to sufficiently evaporate and remove the organic solvent by the solution casting method. Therefore, the melt extrusion method may be used. preferable.

[0014] The cycloolefin-based resin film may be a retardation film having a retardation by being stretched. By using a retardation film, various optical properties can be imparted.

The retardation film is formed by stretching the cycloolefin-based resin film. The cycloolefin-based rosin molecules are oriented in a predetermined direction. As the stretching method, for example, a long cycloolefin-based resin film is stretched in the transverse direction (width direction) in the temperature region near the glass transition temperature Tg of the cycloolefin-based resin, and then longitudinally (long). Length direction), a long cycloolefin-based resin film

In the temperature range near the glass transition temperature Tg of cycloolefin-based resin, a method of simultaneously stretching in the longitudinal direction (length direction) and the transverse direction (width direction), cycloolefin-based resin film is made of cycloolefin-based resin glass. In the temperature region near the transition temperature Tg, a method of applying a pressing force in the thickness direction to form a thin film and simultaneously stretching in the longitudinal direction (length direction) and the transverse direction (width direction) can be mentioned.

[0015] In the laminated optical compensation film of the present invention, the cycloolefin-based resin film has an atmospheric pressure plasma with an inert gas having an oxygen concentration of 15% by volume or less on the surface in contact with the vertical alignment liquid crystal layer. Processed.

By performing the above atmospheric pressure plasma treatment, it becomes easier to apply a liquid crystal solution onto the cycloolefin-based resin film, and the vertically aligned liquid crystal layer and the cycloolefin-based resin film, which have the liquid crystal solution power, are adhered to each other. It will be excellent.

[0016] The normal pressure plasma treatment is a method in which a voltage is applied to a gas introduced between electrodes to be excited into a plasma gas, and a functional group is introduced onto the surface of the object to be processed by the plasma gas. It is.

[0017] The atmospheric pressure plasma treatment is preferably performed in an apparatus having a pair of counter electrodes, and a solid dielectric is installed on at least one of the opposing surfaces of the electrodes. When the solid dielectric is installed on one of the electrodes, the plasma is generated between the solid dielectric and the electrode. When the solid dielectric is installed on both of the electrodes, the plasma is generated between the solid dielectrics. Space. A normal pressure plasma treatment is performed by placing a hydrophobic resin film, which is a target object of the hydrophilic treatment, between the solid dielectric and the electrode or between the solid dielectrics.

[0018] The electrode is not particularly limited, and examples thereof include a simple metal such as copper and aluminum, an alloy such as stainless steel and brass, and a metal compound.

[0019] It is preferable that the counter electrode has a structure in which the distance between the counter electrodes is substantially constant in order to avoid occurrence of arc discharge due to electric field concentration. As an electrode structure that satisfies this condition, Parallel plate type, cylindrical opposed flat plate type, spherical opposed flat plate type, hyperboloid, opposed flat plate type, coaxial cylindrical type structure and the like.

[0020] The solid dielectric is preferably disposed on one or both of the opposing surfaces of the electrode. At this time, the solid dielectric and the electrode on the side to be installed are in close contact with each other, and the opposite surface of the electrode in contact is completely covered. This is because if there is a part where the electrodes face each other directly without being covered by the solid dielectric, a force arc discharge occurs.

The solid dielectric may be in the form of a sheet or a film, but the lower limit of the preferred thickness is 0. Olmm and the upper limit force mm of the preferred thickness. If it is less than 0.01 mm, a high voltage is required to generate discharge plasma, and if it exceeds 4 mm, dielectric breakdown occurs when voltage is applied and arc discharge occurs.

[0021] The material of the solid dielectric is not particularly limited, and examples thereof include plastics such as polytetrafluoroethylene and polyethylene terephthalate, glass, silicon dioxide, aluminum oxide, zirconium dioxide, and titanium dioxide. Examples thereof include metal oxides and double oxides such as barium titanate.

The solid dielectric preferably has a relative dielectric constant of 2 or more in an environment of 25 ° C. Specific examples of the dielectric having a relative dielectric constant of 2 or more include polytetrafluoroethylene, glass, and metal oxide film. Furthermore, in order to generate a high-density discharge plasma stably, it is preferable to use a solid dielectric having a relative dielectric constant of 10 or more.

The upper limit of the relative dielectric constant is not particularly limited, but the actual material is about 18500. The solid dielectric having a relative dielectric constant of 10 or more includes a metal oxide film mixed with 5 to 50% by weight of titanium oxide and 50 to 95% by weight of aluminum oxide, or a metal oxide containing zirconium oxide. It is preferable to use a coating that has a thickness of 10 to L000 μm!

[0022] The distance between the electrodes is not particularly limited, taking into consideration the pressure of the atmospheric gas, the oxygen concentration, the thickness of the solid dielectric, the magnitude of the applied voltage, the purpose of using the plasma discharge-treated film, etc. The preferable lower limit is 0.5 mm, and the preferable upper limit is 50 mm. If the thickness is less than 0.5 mm, the process with large fluctuations in the atmospheric gas concentration between the electrodes tends to be uneven, and the thickness of the workpiece to be installed between the electrodes is limited. Over 50mm In other words, it is difficult to generate a uniform discharge plasma.

The applied voltage is preferably a pulse voltage. The Norse waveform may be an impulse type, square wave type, or modulation type waveform, and even if the applied voltage repeats positive and negative, it is a one-wave shape in which voltage is applied to either the positive or negative polarity side. It may be a waveform.

[0023] The voltage rise time of the pulse voltage is not particularly limited, but the preferred lower limit is 40 ns, and the preferred upper limit is 100 s. Here, the voltage rise time of the pulse voltage means a time during which the voltage change is continuously positive. It is difficult to realize a pulse voltage with a voltage rise time of less than 40 ns, and if it exceeds 100 s, the discharge state becomes easy to move to the arc and becomes unstable, and a high-density plasma state due to the pulse voltage cannot be expected. . A more preferred lower limit is 50 ns, and a more preferred upper limit is 5 μs.

In addition, it is preferable that the time scale of 100 s or less is the same as the voltage rise time of the pulse voltage, in which the voltage fall time of the pulse voltage is preferably steep. For example, in the power supply device used in the embodiment of the present invention, the voltage rise time and the voltage fall time of the pulse voltage can be set to the same time, although it varies depending on the pulse electric field generation technology.

[0024] The frequency of the pulse voltage is not particularly limited, but a preferable lower limit is 0.5 kHz, and a preferable upper limit is 100 kHz. If it is less than 0.5 kHz, the plasma density is low, so it takes too much time to process, and if it exceeds 100 kHz, arc discharge tends to occur. A more preferred lower limit is 1 kHz.

[0025] Although the pulse duration in the pulse voltage is not particularly limited, the lower limit of U is preferably 1 μs, and the preferable upper limit is 1000 μs. If it is less than 1 μs, the discharge becomes unstable, and if it exceeds 1000 s, it tends to shift to arc discharge. A more preferred lower limit is 3 s, and a more preferred upper limit is 200 s. Here, the pulse duration means the time during which the pulse continues in the pulse voltage that is the ON / OFF repetitive force.

Further, in order to stabilize the discharge, it is preferable to have an OFF time that lasts at least 1 s within the discharge time lms. Further, direct current may be superimposed when applying the pulse voltage.

[0026] The atmospheric gas that generates plasma discharge contains at least oxygen gas and has an oxygen concentration. Is an inert gas with a volume of 15% or less. Examples of the mixed gas other than oxygen gas include nitrogen gas and argon gas, and the volume ratio of oxygen gas and gas other than oxygen can be mixed at an almost arbitrary ratio in the range of 15:85 to 1:99. . If the oxygen gas concentration in the mixed gas exceeds 15% by volume, the components derived from oxygen and nitrogen introduced to the surface of the force-treated substrate for which the reason is unknown at this time will decrease, and the adhesion of the polymerizable liquid crystal layer will be reduced. Decreases rapidly. A more preferable upper limit of the oxygen gas concentration is 10% by volume. Further, the lower limit of the oxygen gas concentration in the mixed gas is not particularly limited. In the present invention, since the treatment is carried out near normal pressure, a large amount of equipment is required to make it completely oxygen-free, so there is substantially no such oxygen that is not practical. Permissible.

[0027] The pressure of the atmospheric plasma treatment is not particularly limited, but a preferable lower limit is ΙΟΟΤο rr (about 1.33 X 10 ⁴ Pa), and a preferable upper limit is 800 Torr (about 10.7 X 10 ⁴ Pa). A more preferred lower limit is 700 Torr (about 9.33 × 10 ⁴ Pa), and a more preferred upper limit is 780 Torr (about 10.4 × 10 ⁴ Pa).

[0028] The vertical alignment liquid crystal layer is not particularly limited as long as it is made of a liquid crystal having vertical alignment. As such a vertically aligned liquid crystal layer, for example, the polymer strength of a polymerizable liquid crystal composition containing at least one compound selected from the group consisting of the following formulas (1), (2) and (3): And the like.

[0029] [Chemical 1]

In the above formula (1), W ¹ is hydrogen or methyl, and 1 is an integer of 4-6.

In the above formula (2), W ² and W ³ are hydrogen, chlorine or fluorine, W ⁴ and W ⁵ are hydrogen , Chlorine, methyl or trifluoromethyl, X is a single bond, ethylene bond or ethane bond, and m is an integer of 4-6.

In the above formula (3), n is an integer of 4-6.

[0030] In the above formula (1), a compound in which W ¹ is methyl and m is 4 or 6 can be synthesized by the method described in Japanese Patent Laid-Open No. 2003-238491.

In the above formula (2), W ² and W ³ are hydrogen, W ⁴ and W ⁵ are hydrogen, and X is a single bond.

The compound with m force 6 can be synthesized by the method described in Makromol. Chem. 190, 2255-2268 (1989).

In the above formula (2), W ² and W ³ are hydrogen, W ⁴ is hydrogen, W ⁵ is methyl, X is a single bond, and m-force 6 is It can be synthesized by the method described in Makromol. Chem. 190, 3201—3215 (1989).

[0033] In the above formula (2), W ² and W ³ are hydrogen, W ⁴ is trifluoromethyl, W ⁵ is trifluoromethyl, X is a single bond, and m is 6. Can be synthesized by the method described in JP-A-2004-231638.

[0034] In the above formula (2), W ² and W ³ are chlorine or fluorine, W ⁴ is hydrogen, W ⁵ is chlorine, X is a single bond, and m is 6 Crystals Vol30, No8, 979—

984 (2003).

[0035] In the above formula (3), m force or the compound of 6 is Macromolecules, 26, 6132— 6134 (199

It can be synthesized by the method described in 3).

[0036] In the laminated optical compensation film of the present invention, by controlling the homeotropic alignment of the polymerizable liquid crystal composition, the viewing angle characteristics of a liquid crystal display device using the laminated optical compensation film of the present invention are controlled. Can be improved.

A method for controlling homeotopic orientation is not particularly limited, and examples thereof include a method of adding an organic key compound represented by the following formula (4) to the polymerizable liquid crystal composition.

[0037] [Chemical 2]

_{( 4 )( Four )}

H ₂ N— R ¹ — Si-(-OR ³ ) ₃ _ _r In the above formula (4), R ¹ is a linear alkylene having 2 to 10 carbon atoms, and ¹ to 2 non-adjacent —CH— in the alkylene are replaced by —O or —NH 2.

2

It may be replaced. R ² is methyl, ethyl, propyl or isopropyl. R ³ is methyl, ethyl or trimethylsilyl. R is an integer of 0-2.

That is, the compound (4) is a key compound having an amino group and a hydrolyzable alkoxy group or trimethylsilyloxy group.

[0038] The specific structure of the above formula (4) is not particularly limited, and examples thereof include the following formulas (41) to (415).

[0039] [Chemical 3-1]

NH ₂ ^^ Si (OC ₂ H ₅ ) ₃ (4-1)

^ / ^ Si (OC ₂ H5) ₃

NH (4-2)

OCH ₃

H ₂ NCH ₂ CH ₂ NHCH ₂ CH ₂ Ch½— Si— OCH ₃ (4-3)

CH ₃

H ₂ NCH ₂ CH ₂ NHCH ₂ CH ₂ CH ₂ — Si (OCHa) ₃ (4-4)

H ₂ N (CH2) _e NHCH ₂ CH ₂ CH ₂ -Si (OCH ₃ ) ₃ (4-5)

CH ₃

H ₂ NCH ₂ CH ₂ CH ₂ -Si-OC ₂ H | (4-6)

CH ₃

CH (CH3) ₂

H ₂ NCH ₂ CH ₂ CH ₂ — Si-OC ₂ H ₅ (4-7)

CH (CH ₃ ) ₂

H ₂ NCH ₂ CH ₂ CH ₂ -Si (OChy ₃ (4-8)

OC ₂ H ₅

H ₂ NCH ₂ CH ₂ CH ₂ _S to CH ₃ (4-9)

OC, H =

(4-10)

H

[Chemical 3-2] -CH,

H C.

H N -O

(Four-

CH ₃

In order to obtain a defined homeotopick pick orientation, the amount of the organic silicon compound is preferably The lower limit is 0.01 parts by weight with respect to the polymerizable liquid crystal compound, the preferred upper limit is 0.30 parts by weight, the more preferred lower limit is 0.03 parts by weight, and the more preferred upper limit is 0.20 parts by weight. A preferred upper limit is 0.15 parts by weight.

[0041] The method for producing the laminated optical compensation film of the present invention is not particularly limited. For example, a normal-pressure plasma treatment is performed on a polyolefin resin film using an inert gas having an oxygen concentration of 15% by volume or less. And the polymerizable liquid crystal composition serving as a raw material for the vertical alignment liquid crystal layer was dissolved in a solvent on the surface of the cycloolefin-based resin film subjected to the normal pressure plasma treatment and subjected to the normal pressure plasma treatment. And a step of applying a liquid crystal solution and drying.

Such a method for producing a laminated optical compensation film is also one aspect of the present invention.

[0042] The solvent for dissolving the polymerizable liquid crystal composition is not particularly limited. For example, benzene, toluene, xylene, mesitylene, n-butylbenzene, jetylbenzene, tetralin, methoxybenzene, 1,2-dimethoxybenzene , Ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, cyclohexanone, ethyl acetate, ethyl lactate, methyl lactate, ethylene glycol monomethino ethenore acetate, propylene glycol monomono main Chino Les ether Honoré acetate, propylene glycol Honoré monomethyl E Chino les ether Honoré acetate, _I Buchirorataton, 2-pyrrolidone, Nyu- methyl 2-pyrrolidone, dimethyl formamide, black hole Hol , Dichloromethane, carbon tetrachloride, dichloroethane, tetrachloroethylene, trichloroethylene, ethylene, tetrachloroethylene, black benzene, t-butyl alcohol, diacetone alcohole, glycerin, monoacetin, ethylene glycol, triethylene glycol, hexylene glycol, ethylene glycol Monomethinoreethenore, ethinorescenoresonoleb, butyrcellsolve and the like. The solvent may be a single compound or a mixture.

[0043] The proportion of the solvent is not particularly limited, but the preferred lower limit is 60 wt% and the preferred upper limit is 98 wt% based on the total amount of the polymerizable liquid crystal composition solution. If the amount is less than 60% by weight, the solubility of the polymerizable liquid crystal compound and the optimum viscosity may not be obtained when the polymerizable liquid crystal composition solution is applied. Steaming The time and heat amount at the time of emission and the economic viewpoint power are also favorable. More preferably, the lower limit is 50% by weight, and the more preferable upper limit is 90% by weight, the still more preferable lower limit is 70% by weight, and the upper limit is more preferably 85% by weight.

[0044] In order to optimize the polymerization rate of the polymerizable liquid crystal composition, a known photopolymerization initiator may be used. The preferred addition amount of the photopolymerization initiator is not particularly limited, but based on the total amount of the composition, the preferred lower limit is 0.01% by weight, the preferred upper limit is 10% by weight, the more preferred lower limit is 0.1% by weight, A more preferred upper limit is 7% by weight.

[0045] The photopolymerization initiator is not particularly limited, and examples thereof include 2 hydroxy-2-methyl-1-phenylpropane-1-one, 1-hydroxycyclohexyl phenyl ketone, 2,2-dimethoxy-1,2, Diphenylane 1-On, Irgacure 1 500, Irgacure 1 2959, Irgacure 1 907, Irgacure 1 369, Irgacure 1300, Irgaki Your 819, Irgacure 1700, Irgacure 1800, Irgacure 1800, Icg 1 784, Irgacure 1 754, Irgacure 1 OXE01, p-methoxyphenyl-1,2,4 bis (trichloromethyl) triazine, 2- (p-butoxystyryl) -1,5 trichloromethyl-1,3,4-oxadiazole, 9 Luacridine, 1-(4-Isopropylphenol) 2 Hydroxy 1 2-Methylpropane 1 1-one, benzyldimethyl ketal, 2-methyl-1- [4 (methylthio) phenol] 2 morpholinopropane 1-one, and a mixture of 2,4 jetylxanthone and methyl p-dimethylaminobenzoate. Both Darocur 1 and Irgacure 1 are manufactured by Ciba 'Specialty' Chemicals. Furthermore, known sensitizers (isopropyl thixanthone, jetyl thioxanthone, etc.) may be added thereto.

[0046] Other examples of the photo radical polymerization initiator include, for example, p-methoxyphenol-2,4 bis (trichloromethyl) triazine, 2- (p-butoxystyryl) -15 trichloromethyl 1, 3, 4 —Oxadiazole, 9 phenacridine, 9, 10 benzphenazine

, Benzophenone Z Michler's ketone mixture, Hexalylbiimidazole Z Mercapto benzimidazole mixture, 1— (4-Isopropylphenol) 2 Hydroxy-2-methylpropane 1-one, Benzyldimethyl ketal, 2-Methyl-1 [4 (Methyl Thio) fuel] 2 morpholinopropane 1-on, 2, 4 jetylxanthone Zp -Methyl dimethylaminobenzoate mixture, benzophenone z methyltriethanolamine mixture, etc.

[0047] The coating method is not particularly limited, and examples thereof include a die coating method, a roll coating method, a gravure coating method, a micro gravure method, a spin coating method, and a bar coating method. In the laminated optical compensation film of the present invention, it is possible to easily apply the liquid crystal solution to the cycloolefin-based resin film by performing the plasma discharge treatment step, and after the application, the liquid crystal solution can be applied. The adhesion between the layer and the cycloolefin-based resin film is extremely excellent.

[0048] When the liquid crystal solution is applied, the solvent is removed after the application, and the layer of the polymerizable liquid crystal composition having a uniform film thickness on the cycloolefin-based resin film, that is, the vertical alignment liquid A crystal layer is formed. The conditions for removing the solvent are not particularly limited. If the solvent is almost removed and the coating film of the polymerizable liquid crystal composition is no longer fluid, it is dried. The solvent can be removed by air drying at room temperature, drying on a hot plate, drying in a drying oven, or blowing of warm or hot air. Depending on the type and composition ratio of the compound used in the polymerizable liquid crystal composition, the nematic alignment of the polymerizable liquid crystal composition in the coating film may be completed in the process of drying the coating film. Therefore, the coating film that has undergone the drying step can be subjected to a polymerization step that does not go through a heat treatment step that will be described later. However, in order to make the orientation of the liquid crystal molecules in the coating film more uniform, it is preferable to heat-treat the coating film that has undergone the drying step and then to perform photopolymerization.

[0049] The temperature and time when heat-treating the coating film, the wavelength of light used for light irradiation, the amount of light irradiated from the light source, and the like are the types and composition ratios of the compounds used in the polymerizable liquid crystal composition, and photopolymerization. The preferred range varies depending on whether or not an initiator is added and the amount added. Accordingly, the conditions regarding the temperature and time of the heat treatment of the coating film described below, the wavelength of light used for light irradiation, and the amount of light irradiated from the light source are merely an approximate range.

[0050] The heat treatment of the coating film may be performed at a temperature equal to or higher than the liquid crystal phase transition point of the polymerizable liquid crystal composition, which is preferably performed under the condition that the solvent is removed and the uniform orientation of the polymerizable liquid crystal is obtained. Examples of the heat treatment method include a method in which the coating liquid is heated to a temperature at which the polymerizable liquid crystal composition exhibits a nematic liquid crystal phase to form a nematic alignment in the polymerizable liquid crystal composition in the coating film. Can be mentioned. Nematic alignment may be formed by changing the temperature of the coating film within a temperature range in which the polymerizable liquid crystal composition exhibits a nematic liquid crystal phase. This method is a method in which the nematic orientation is generally completed in the coating film by heating the coating film to a high temperature range within the above temperature range, and then the order is further ordered by lowering the temperature. In either of the above heat treatment methods, the preferred lower limit of the heat treatment temperature is room temperature, the preferred upper limit is 120 ° C, the more preferred upper limit is 90 ° C, and the still more preferred upper limit is 70 ° C.

The preferable lower limit of the heat treatment time is 5 seconds, and the preferable upper limit is 40 minutes, the more preferable lower limit is 10 seconds, the more preferable upper limit is 10 minutes, the more preferable lower limit is 20 seconds, and the more preferable! /, The upper limit is 5 minutes. In order to raise the temperature of the layer made of the polymerizable liquid crystal composition to a predetermined temperature, the heat treatment time is preferably 5 seconds or longer. In order not to lower the productivity, it is preferable to set the heat treatment time within 2 hours. In this way, the polymerizable liquid crystal layer of the present invention is obtained.

The wavelength of light used for the light irradiation is not particularly limited, but a preferred lower limit is 150 nm, a preferred upper limit is 500 nm, a more preferred lower limit is 250 nm, a more preferred upper limit is 45 Onm, a further preferred lower limit is 300 nm, and further preferred. The upper limit is 400 nm. As the light, for example, electron beams, ultraviolet rays, visible rays, infrared rays (heat rays) or the like can be used. Usually, ultraviolet rays or visible rays may be used. Specific examples of light sources include, for example, low-pressure mercury lamps (sterilization lamps, fluorescent chemical lamps, black lights), high-pressure discharge lamps (high-pressure mercury lamps, metal nitride lamps), short arc discharge lamps (extra-high-pressure mercury lamps) Xenon lamp, mercury xenon lamp) and the like. Among these, a metal nano lamp, a xenon lamp, and a high-pressure mercury lamp are preferably used. The wavelength region of the irradiation light source may be selected by installing a filter or the like between the light source and the polymerizable liquid crystal layer and passing only a specific wavelength region. The amount of light emitted from the light source particularly limited, such Iga, preferable lower limit is 2MjZcm ^2, a preferred upper limit is 5000MiZcm ^2, more preferably not lower limit 10MiZcm ^2, a more preferred upper limit is 3000MiZcm ^2, still more preferred lower limit 100 mjZcm ² and a more preferable upper limit is 2000 mjZcm ² . The temperature condition during light irradiation is preferably set in the same manner as the above heat treatment temperature. [0052] The laminated optical compensation film of the present invention obtained by using such a vertically aligned liquid crystal layer can exhibit extremely high performance.

[0053] In the laminated optical compensation film of the present invention, the cycloolefin-based resin film and the vertically oriented liquid crystal layer have an adhesion evaluation measured by a method according to the cross-cut method of JIS K 5600-5-6 of 0 to Preferred to be two categories. The adhesion evaluation is classified into 0-2, which means that the adhesion between the cycloolefin-based resin film and the vertical alignment liquid crystal layer is excellent, and the durability of the laminated optical compensation film of the present invention is excellent. It becomes.

The invention's effect

[0054] According to the present invention, by selecting a base material having a cycloolefin-based resin film strength, birefringence hardly changes even if some stress is applied to the base material due to the heat generation of the knock light, so that light leakage is prevented. In this way, the coating properties of the liquid crystal solution, which was a problem with cycloolefin-based resin films, can be remarkably improved, and a laminated optical compensation film with excellent adhesion to the liquid crystal layer is provided. can do. That is, it is possible to contribute to the improvement of work efficiency without unexpected peeling between the substrate and the liquid crystal layer during rework. In the present invention, the homeotropic alignment of the liquid crystal layer can be easily controlled by using the vertical alignment liquid crystal layer in particular.

Since the laminated optical compensation film of the present invention uses a cycloolefin-based resin film that is excellent in transparency and heat resistance and has a small photoelastic coefficient, it is heated by the heat generated by the knock light, and some stress is applied to the substrate. Even so, the birefringence hardly changes, and display defects such as light loss may not occur! /.

ADVANTAGE OF THE INVENTION According to this invention, the laminated optical compensation film used for the improvement of the image quality of a liquid crystal display device can be provided.

BEST MODE FOR CARRYING OUT THE INVENTION

[0055] Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

[Example 1]

(Production of cycloolefin film)

Thermoplastic saturated norbornene-based resin (manufactured by Nippon Zeon Co., Ltd.) as cycloolefin-based resin The product name “Zeonor # 1420”) is supplied to a single-screw extruder, melted and kneaded, and the T-die force attached to the tip of the single-screw extruder is also melt-extruded to a width of 650 mm and flat. A long film having a uniform thickness of 65 μm was obtained.

[0057] (Atmospheric pressure plasma treatment)

Figure 1 shows the plasma discharge treatment equipment. In the metal chamber 1, the upper electrode 2 (made of stainless steel (SUS304), size: 150 mm X 100 mm) and the lower electrode 3 (made of stainless steel (SUS30 4), size: 150 mm X 100 mm) are placed in the metal chamber 1. It is arranged in a state insulated from 1. The distance between the electrodes is 2mm. The electrode facing surfaces of the upper electrode 2 and the lower electrode 3 are covered with a sprayed film 4 of AlO having a thickness of 1.5 mm.

twenty three

After placing the cycloolefin-based resin film 7 in the middle of the upper electrode 2 and the lower electrode 3, evacuation was performed with an oil rotary pump until the inside of the apparatus reached lTorr (about 133 Pa). After evacuation, a mixed gas in which nitrogen and oxygen were mixed at a volume ratio of 95: 5 was introduced from the gas introduction pipe 5 until the inside of the apparatus reached 760 Torr (about 1.01 X 10 ⁵ Pa).

A pulsed power supply 6 applies an AC pulse voltage between the electrodes with a rise time of 5 μs, a pulse width of 100 μs, a frequency of 7 kHz, and a voltage of 5 kV between the electrodes to perform plasma discharge. Plasma discharge treatment was performed on one side of the film. The cycloolefin-based resin film 7 was subjected to plasma discharge treatment while moving between the upper electrode 2 and the lower electrode 3 at a speed of 4 mZ.

[0058] (Synthesis of polymerizable liquid crystal compound (5))

(Stage 1)

While stirring a solution of 3- (4 hydroxyphenol) propionic acid (1150 g) in ethanol (1500 mL), sulfuric acid (230 g) was added dropwise over 10 minutes and then refluxed for 5 hours. The reaction solution was concentrated, and the obtained concentrated solution was poured into water (lOOOOmL), and ethyl acetate was added and stirred. After liquid separation, the ethyl acetate layer was neutralized with a saturated sodium carbonate solution, washed with a small amount of water, and then dried over anhydrous magnesium sulfate. Ethyl acetate and unreacted components were distilled off from this ethyl acetate layer to obtain 1400 g of concentrate. The concentrate was purified by distillation under reduced pressure to obtain 1144 g of ethyl 3- (4 hydroxyphenol) propionate. The boiling point was 160 ° CZ4. [0059] (second stage)

Six acetic anhydride (800 g) was added to acetic anhydride (1200 mL) cooled to 10 ° C. with an ice bath, and then pyridine (934 g) was added dropwise over 10 minutes. After defeating the enemy, it was refluxed for 2 hours. The reaction solution was poured into water, and toluene was added thereto and stirred. The toluene layer was separated, neutralized with a saturated aqueous sodium carbonate solution, and washed with a small amount of water. Then, it dried with anhydrous magnesium sulfate. Toluene and unreacted components were distilled off from this toluene layer to obtain a concentrate. The concentrate was purified by distillation under reduced pressure to obtain 983 g of 6-acetoxychlorohexane. The boiling point was 82 ° CZ5.3 hPa.

[0060] (Stage 3)

Ethyl 3- (4 hydroxyphenol) propionate (400 g) was dissolved in dimethylformamide (28 OOmL). Thereto was added sodium hydroxide (98 g), and the mixture was stirred at 40 ° C for 30 minutes. The formation of salt could be observed visually. 6-acetoxychlorohexane (515 g) was stirred at 80 ° C. for 7 hours. The reaction solution was poured into water (2000 mL), and toluene was added thereto and stirred. After separation, the toluene layer was washed with 6N hydrochloric acid, saturated sodium carbonate solution and water in that order, and dried over anhydrous magnesium sulfate. This toluene layer strength also distilled off the solvent to obtain 709 g of concentrate. Sodium hydroxide (185 g) was dissolved in water (400 mL), ethanol (600 mL) and 709 g of concentrate were added and heated, and the mixture was refluxed for 2 hours. The reaction solution was concentrated under reduced pressure using an evaporator, and the resulting concentrate was poured into 6N hydrochloric acid. The resulting slurry was filtered to obtain a solid, which was recrystallized with ethanol to obtain 28 lg of (4- (6-hydroxyhexoxy) phenol) propionic acid. The melting point was 109-112 ° C.

[0061] (Stage 4)

(4- (6Hydroxyhexyloxy) phenol) propionic acid (200 g), N, N-dimethyllaurin (lOOg) and BHT (0.3 g) were dissolved in dioxane (lOOOmL). Then hair chloric acid chloride (74.3 g) was added dropwise over 10 minutes and stirred at 60 ° C. for 5 hours. The reaction solution was poured into water, ethyl acetate was added and stirred. The ethyl acetate layer was separated, washed with water, and dried over anhydrous magnesium sulfate. The ethyl acetate layer strength solvent was distilled off to obtain a solid. This solid was dissolved in toluene, poured into a large amount of heptane, and reprecipitated to obtain 213 g of (4 ((6-allyloyloxyhexyloxy) phenol) propionic acid. Fusion The point was 64-68 ° C.

[0062] (5th stage)

(4- (6 acryloxyhexyloxy) phenol) propionic acid (150 g), 2, 3 bis (trifluoromethyl) hydroquinone (52.2 g), BHT (0.775 g), dimethylaminopyridin (15 g) was dissolved in methylene chloride (900 ml). To this solution, a solution of DCC (N, N, -dicyclohexylcarbodiimide) (100 g) dissolved in methylene chloride (300 mL) was added dropwise over 1 hour. After further stirring for 2 hours, water was added to separate the layers. The methylene chloride layer was washed with 6N hydrochloric acid and 10% aqueous sodium hydroxide and dried over anhydrous magnesium sulfate. The concentrate obtained from the salt methylene layer was purified by silica gel column chromatography to obtain 125 g of a polymerizable liquid crystal compound (5) represented by the following formula (5).

[0063] (Synthesis of polymerizable liquid crystal compound (6))

(Stage 1)

A mixture of fluorene (78.3 g) and THF (700 mL) was cooled to −70 ° C., and n-BuLi (300 mL, corresponding to 0.47 mol) was added dropwise while maintaining the temperature at −60 ° C. or lower. Subsequently, methyl iodide (66.8 g) was added and gradually returned to room temperature. The mixture was cooled again to 0 ° C, 3M-hydrochloric acid (300 mL) was added, and the reaction mixture was extracted with toluene. The obtained organic layer was washed thoroughly with saturated sodium hydrogen carbonate, saturated sodium hydrogen sulfite and water successively and dried over anhydrous magnesium sulfate. The solvent was removed from the organic layer under reduced pressure, and the residue was purified by column chromatography (silica gel, eluent: toluene Z heptane [40Z60]) and recrystallization (ethanol). —Methylfluorene (57.4 g) was obtained. The melting point is 47.3-48.8. C.

[0064] (Second stage)

Anhydrous aluminum chloride (162.7 g) was added to a mixture of 9 methylfluorene (55 g) and methylene chloride (800 mL) while maintaining the temperature below 0 ° C. to obtain a dark green reaction mixture. To this mixture, a solution of acetyl acetate (47.9 g) in methylene chloride (200 mL) was added dropwise while maintaining 0 ° C., and the mixture was gradually returned to room temperature and stirred for 12 hours. The reaction mixture was poured into a mixture of 6M hydrochloric acid and ice, and the organic layer was separated. This organic layer was thoroughly washed with saturated sodium hydrogen carbonate and water successively and dried over anhydrous magnesium sulfate. From this organic layer The solvent was removed under reduced pressure, and the resulting residue was purified by column chromatography (silica gel, eluent: heptane Z ethyl acetate [7Z3]) and recrystallized (ethanol) to give 2,7 diacetyl- 9-methylfluorene (30 g) was obtained. The melting point is 127.9-129.0. C.

[0065] (Stage 3)

2, 7 Diacetyl- 9 Methylfluorene (30 g), methylene chloride (300 mL), acetic anhydride (35 g) and 34% hydrogen peroxide-hydrogenated water (34.6 g) were mixed with 36 M sulfuric acid (12 mL) at 3 ° C. It was dropped slowly while maintaining the following. The resulting mixture was stirred at 24 ° C for 7 hours and poured into water. The separated organic layer was thoroughly washed with saturated sodium hydrogen carbonate, 10% sodium hydrogen sulfite and water successively and dried over anhydrous magnesium sulfate. The solvent was removed from the organic layer under reduced pressure, and the resulting residue was purified by column chromatography (silica gel, eluent: heptane Ztoluene [6Z4]) and recrystallization (ethanol). , 7 Diacetyloxy 9 methylfluorene (12.4 g) was obtained. The melting point is 138.6 to 139.7. C.

[0066] (Stage 4)

A mixture of 2,7 diacetyloxy 9 methylfluorene (12 g), lithium hydroxide monohydrate (3.42 g) and ethylene glycol (120 mL) was heated to reflux for 1 hour. The reaction mixture was poured into 6M-hydrochloric acid and extracted with ethyl acetate. The organic layer was sufficiently washed with water and dried over anhydrous magnesium sulfate. The solvent was removed from the organic layer under reduced pressure to obtain 2,7 dihydroxy mono 9-methylfluorene (7.24 g) as pale brown crystals. The melting point is 191.5-196.3. C.

[0067] (5th stage)

2, 7 Dihydroxy mono 9-methyl fluorene (0.5 g), 4— (6-Atalyloxyhexyloxy) benzoic acid (1.52 g), EDC (ethylene dichloride, 0.99 g), DMAP (4— A mixture of dimethylaminopyridine, 5.76 mg) and methylene chloride (30 mL) was stirred at room temperature for 12 hours. Water was added to the reaction mixture, and the separated organic layer was washed with water and then dried over anhydrous magnesium sulfate. The solvent was removed from the organic layer under reduced pressure, and the resulting residue was subjected to force chromatography (silica gel, eluent: toluene Z ethyl acetate [95Z5]) and re-reacted. Purification by crystals (ethanol Z ethyl acetate) gave 0.19 g of a polymerizable liquid crystal compound (6) represented by the following formula (6).

[0068] (Synthesis of polymerizable liquid crystal compound (7))

ω-Bromohexanoic acid (33.6 g) and chlorothionyl (20.5 g) were refluxed in benzene, and lTorr was distilled under reduced pressure to collect a 143-145 ° C fraction, and the corresponding acid chloride (31.3 g) was recovered. Obtained.

Next, in anhydrous ether at 20 ° C, LiAlH 5.6 g was added for reduction, and ω bromo

Four

Alcohol 14. Og was obtained.

This was refluxed for 12 hours in methanol with 18. lg of potassium salt of 4-hydroxy-1,4-syanobiphenol obtained from 4-hydroxy-1,4-sianobiphenol and KOH. After the reaction, extraction with water-closure form, washing with water, and concentration through an Al 2 O column, the residue is bent.

twenty three

Recrystallization from zen yielded 12.6 g of 4 (hydroxohexyloxy) 4, 1-sianobiphenyl.

This was reacted with 3.8 g of acrylic acid chloride in the presence of triethylamine in anhydrous benzene at room temperature. The reaction solution was washed with water and dried over MgSO.

Four

And recrystallized. Next, the mixture was passed through a silica gel column with benzene as a solvent and recrystallized once again with methanol to obtain 10. Og of a polymerizable liquid crystal compound (7) represented by the following formula (7).

[0069] (Preparation of polymerizable liquid crystal composition)

Polymerizable liquid crystal compound (5) 20% by weight, polymerizable liquid crystal compound (6) 60% by weight, polymerizable liquid crystal compound (7) 20% by weight of photopolymerization initiator Irgacure No. 'Specialty' Chemicals) and a compound (8) with a weight ratio of 0.10 (Sila Ace S330, Chisso) were added. Toluene was added to this composition to prepare a polymerizable liquid crystal composition solution (liquid crystal solution) having a solvent content of 75% by weight.

[0070] [Chemical 4]

(6)

-o «. -(7)

O

OC ₂ H ₅

I

NH ₂ -CH ₂ CH ₂ CH ₂ -Si— OC ₂ H ₅ (8)

OC ₂ H ₅

[0071] (Production of laminated optical compensation film)

A polymerizable liquid crystal composition solution (liquid crystal solution) was applied to the surface-treated surface of a cycloolefin-based resin film held on a 10 cm × 10 cm glass substrate by spin coating at 2000 rpm for 20 seconds. After coating, the solvent was dried on a hot plate kept at 70 ° C. Furthermore, this was cured by irradiating with a UV lamp with a UV lamp to produce a laminated optical compensation film. The integrated dose was 400 mJ and the oxygen concentration in the atmosphere was 5%.

[Example 2]

A laminated optical compensation film was produced in the same manner as in Example 1 except that the mixed gas concentration during normal pressure plasma treatment was changed to nitrogen: oxygen = 90: 10.

[0073] (Example 3)

Example 1 except that the mixed gas concentration during normal pressure plasma treatment was nitrogen: oxygen = 85: 15 A laminated optical compensation film was produced in the same manner.

[0074] (Comparative Example 1)

A laminated optical compensation film was produced in the same manner as in Example 1 except that a normal cycloolefin-based resin film was used after being subjected to atmospheric pressure plasma treatment.

[0075] (Comparative Example 2)

Instead of atmospheric pressure plasma treatment, use a corona discharge treatment device (high frequency power supply device AGI-020) manufactured by Kasuga Denki Co., Ltd. with a treatment strength of 0.2 kW and a speed of 4. OmZ for one side of a cycloolefin-based resin film. A laminated optical compensation film was produced in the same manner as in Example 1 except that the discharge treatment was performed.

[0076] (Comparative Example 3)

A laminated optical compensation film was produced in the same manner as in Example 1 except that the mixed gas concentration during atmospheric pressure plasma treatment was changed to nitrogen: oxygen = 79: 21 (atmosphere).

[0077] (Comparative Example 4)

A laminated optical compensation film was produced in the same manner as in Example 1 except that the mixed gas concentration during normal pressure plasma treatment was changed to nitrogen: oxygen = 1: 99.

[0078] <Evaluation>

The following evaluation was performed for the production steps of the laminated optical compensation film and laminated optical compensation film obtained in Examples 1 to 3 and Comparative Examples 1 to 4. The results are shown in Table 1.

[0079] (Contact angle measurement)

The contact angle between the cycloolefin-based resin film and the liquid crystal solution when the liquid crystal solution was applied onto the cycloolefin-based resin film was measured with G2 manufactured by KRUSS.

[0080] (Repel evaluation)

When the liquid crystal solution was applied onto the cycloolefin-based resin film, the repelling condition of the liquid crystal solution with respect to the cycloolefin-based resin film was visually observed and evaluated according to the following criteria.

〇 Uniform coating was possible without repelling.

Δ: Unevenness occurred due to slight repelling, but coating was possible.

It was difficult to coat uniformly due to X repelling. [0081] (Adhesion evaluation)

For the laminated optical compensation film obtained, the adhesion of the liquid crystal layer to the cycloolefin-based resin film was measured and evaluated by a method according to the cross-cut method (lmm width 100 mass) of JIS K 5600-5-6. .

[0082] (Vertical orientation)

Using the phase difference measuring device KOBRA-21ADH (manufactured by Oji Scientific Instruments Co., Ltd.) for the obtained laminated optical compensation film, the phase difference in the front direction and the normal line to the film surface were measured at nine points in the plane. In addition, all azimuth phase differences were measured from 45 ° tilted direction at azimuth angle intervals of 15 degrees, and the values obtained by correcting the phase difference of the substrate were obtained. The vertical alignment was evaluated according to the following criteria.

〇 The front phase difference was 2nm or less at all measurement points, and the variation in the phase difference from the oblique 45 ° direction was 5nm or less.

Δ 1 point or more, force with front phase difference of 2 nm or more, dispersion force of phase difference from 45 degrees direction S5 nm or more.

X In the appearance test, the front and oblique directions were strong.

[0083] (Appearance)

The obtained laminated optical compensation film was sandwiched between polarizing plates arranged in a cross-col and evaluated visually.

[0084] [Table 1]

Industrial applicability

According to the present invention, a laminated optical compensation film used for improving the image quality of a liquid crystal display device is provided. Can be provided.

Brief Description of Drawings

FIG. 1 is a schematic diagram showing an example of a plasma discharge treatment apparatus.

Explanation of symbols

[0087] 1 Metal chamber

2 Upper electrode

3 Lower electrode

4 Solid dielectric coating

5 Gas inlet pipe

6 Pulse power supply

7 Cycloolefin-based resin film

Claims

The scope of the claims

[1] A laminated optical compensation film comprising a cycloolefin-based resin film and a vertically-aligned liquid crystal layer laminated on the cycloolefin-based resin film,

The cycloolefin-based resin film is formed on the surface in contact with the vertical alignment liquid crystal layer.

Atmospheric pressure plasma treatment with an inert gas whose oxygen concentration is 15% by volume or less has been performed.

A laminated optical compensation film characterized by the above.

[2] The vertical alignment liquid crystal layer is at least selected from the group consisting of the following formulas (1), (2) and (3)

2. The laminated optical compensation film according to claim 1, wherein the polymer power of the polymerizable liquid crystal composition containing one kind of compound.

[Chemical 1]

In the above formula (1), Wi is hydrogen or methyl, and 1 is an integer of 4-6.

In the above formula (2), W ² and W ³ are hydrogen, chlorine or fluorine, W ⁴ and W ⁵ are hydrogen

, Chlorine, methyl or trifluoromethyl, X is a single bond, ethylene bond or ethane bond, and m is an integer of 4-6.

In the above formula (3), n is an integer of 4-6.

The cycloolefin-based resin film and the vertically aligned liquid crystal layer are characterized in that the adhesion evaluation measured by a method according to the cross-cut method of JIS K 5600-5-6 is 0 to 2 classification. 2. The laminated optical compensation film according to 2. A process for performing an atmospheric pressure plasma treatment using an inert gas having an oxygen concentration of 15% by volume or less on the cycloolefin-based resin film, and an atmospheric pressure of the cycloolefin-based resin film subjected to the atmospheric pressure plasma treatment A laminated optical compensation film comprising a step of applying a liquid crystal solution obtained by dissolving a polymerizable liquid crystal composition, which is a raw material of a vertical alignment liquid crystal layer, into a solvent on a surface subjected to plasma treatment, and drying the solution. Manufacturing method.