KR100746807B1 - Manufacturing method of optical laminate, and elliptic polarizing plate and circular polarizing plate composed of the laminate, and liquid crystal display apparatus - Google Patents

Abstract

After adhering the liquid crystal material layer in which the liquid crystal alignment formed on the alignment substrate is fixed to the releasable substrate via the adhesive layer, the alignment substrate is peeled off to transfer the liquid crystal material layer to the releasable substrate, and the releasable substrate / adhesive is A 1st process of obtaining the laminated body (A) which consists of a layer / liquid crystal material layer, or the liquid crystal material layer by which the liquid crystal orientation formed on the orientation substrate was fixed was adhere | attached with the removable substrate 1 via the adhesive bond layer 1 After peeling the alignment substrate, the liquid crystal material layer is transferred to the re-peelable substrate 1, and then the re-peelable substrate 2 and the liquid crystal material layer are adhered to each other via the adhesive layer 2. 1) peeling 1) and obtaining the laminated body A which consists of an adhesive bond layer 1 / liquid-crystal material layer / adhesive agent 2 / re-removable substrate 2 formed by transferring to the removable board | substrate 2 The process and the polymer stretched film and the polarizing plate are contacted via an adhesive and an adhesive 2nd process of obtaining the laminated body (B) which consists of a polarizing plate / adhesive agent (adhesive) layer / polymer stretched film, and before laminating | stacking or after laminating | stacking the said laminated body (A) and laminated body (B) a laminated body ( It is a method of manufacturing an optical laminated body by passing each process of the 3rd process of peeling the re-peelable board | substrate of A). This manufacturing method provides a manufacturing method for laminating an optical element comprising a liquid crystal material layer without a supporting substrate film.

Description

MANUFACTURING METHOD OF OPTICAL LAMINATE, AND ELLIPTIC POLARIZING PLATE AND CIRCULAR POLARIZING PLATE COMPOSED OF THE LAMINATE, AND LIQUID CRYSTAL DISPLAY APPARATUS

This invention relates to the manufacturing method of the optical laminated body useful for various optical elements. Moreover, this invention relates to the elliptical polarizing plate or circular polarizing plate which consists of an optical laminated body obtained by such a manufacturing method, or relates to the liquid crystal display device provided with the said elliptical polarizing plate or circular polarizing plate.

A thin film (film) consisting of an alignment layer of a liquid crystal compound, in particular a film made of a liquid crystal material in which a nematic structure, a torsional nematic structure, or a nematic hybrid structure is immobilized, is used as a color compensation device for a liquid crystal display device or a viewing angle compensation device. Moreover, it has excellent performance as a optical optical element etc., and contributes to the high performance and light weight of various display elements. As a manufacturing method of these films, the method of transferring the layer which consists of the liquid crystal substance formed on the oriented board | substrate on the translucent board which also serves as a support substrate is proposed (for example, Unexamined-Japanese-Patent No. 4-57017, Unexamined-Japanese-Patent). See JP-A-177216). Moreover, as a countermeasure for enduring the severe durability test required for a liquid crystal display element, the manufacturing method of the optical element which consists of a liquid crystal material which does not use a support substrate film for further thinning and weight reduction is also proposed (for example, , Japanese Patent Application Laid-Open No. 8-278491. According to this manufacturing method, an optical element comprising a liquid crystal material layer without a supporting substrate film is obtained by transferring a layer of a liquid crystal material oriented on an orientation substrate to a re-peelable substrate after an adhesive, and then peeling the re-peelable substrate. It is possible to manufacture.

On the other hand, about the optical film used for various display apparatuses, such as a liquid crystal display device, more high optical performance is calculated | required in recent years, and only one optical film cannot satisfy | require a request, and many are used by laminating | stacking. ought. For example, 1/4 wavelength plate and 1/2 in the lamination | stacking of the polymer stretched film represented by the polycarbonate in the retardation film for color compensation of STN liquid crystal display device, and the circularly polarizing plate for transflective reflection type liquid crystal display devices. A broadband circular polarizing plate etc. are mentioned by laminating | stacking the broadband quarter wave plate by lamination | stacking with a wavelength plate, or the cholesteric film which has another selective wavelength range. Here, the broadband quarter wave plate by lamination of the quarter wave plate and the half wave plate is laminated by, for example, a method as disclosed in Japanese Patent No. 3236304, and assembled into a liquid crystal display device as a circular polarizer. Used. On the other hand, high functionalization by lamination of such an optical film, as represented by mobile phones and portable information terminal devices that are widely spread in recent years, the demand for thinning and weight reduction is also very high. Along with this, thinning and weight reduction are also desired for the optical film used for the display device. For this reason, attempts have also been made to make polymer stretched films thinner, but there are limitations to thinning polymer stretched films due to optical characteristics and manufacturing process constraints. there was.

In order to solve such a problem, it can be considered effective to use an optical element made of a liquid crystal material that does not use a supporting substrate film such as Japanese Patent Application Laid-open No. Hei 8-278491 described above. No conventional method has been established.

An object of the present invention is to achieve high functionality of an optical characteristic surface that is difficult only with a polymer stretched film and to realize a significant reduction in thickness. That is, as a result of earnestly examining about the manufacturing method for laminating | stacking the optical element which consists of a liquid crystal material layer without a support substrate film, focusing on the optical film which consists of a liquid crystal material layer which can express thinner and excellent optical function, The invention has been completed.

That is, according to the first aspect of the present invention, the liquid crystal material layer having the liquid crystal alignment formed on the (1) alignment substrate is adhered to the repeelable substrate through the adhesive layer, and then the alignment substrate is peeled off to re-peel the liquid crystal material layer. 1st process of transferring to a board | substrate, and obtaining the laminated body which consists of a re-peelable board | substrate / adhesive layer / liquid crystal material layer (A; it is not code | symbol, it is code | symbol for identification), (2) A polymer stretched film and a polarizing plate adhesive, 2nd process of bonding through an adhesive bond layer, obtaining a laminated body (B) which consists of a polarizing plate / adhesive (adhesive) layer / polymer stretched film, and (3) before bonding the said laminated body (A) and a laminated body (B), Or it is related with the manufacturing method of the optical laminated body characterized by passing through at least each process of the 3rd process of peeling the repeelable board | substrate of laminated body (A) after bonding.

According to the second aspect of the present invention, the liquid crystal material layer on which the liquid crystal alignment formed on the (1) alignment substrate is fixed is subjected to the re-peelable substrate 1 through the adhesive layer 1 (not the reference numeral, the reference numeral). After the adhesion, the alignment substrate is peeled off to transfer the liquid crystal material layer to the releasable substrate 1, and then the releasable substrate 2 and the liquid crystal material layer are adhered to each other via the adhesive layer 2. The agent which peels (1) and obtains the laminated body A which consists of an adhesive bond layer 1 / liquid-crystal material layer / adhesive agent 2 / re-removable substrate 2 formed by transferring to the removable board | substrate 2 1st process, (2) 2nd process of joining a polymeric stretched film and a polarizing plate through an adhesive and an adhesive bond layer, and obtaining a laminated body (B) which consists of a polarizing plate / adhesive (adhesive) layer / polymer stretched film, and (3) the said laminated body Re-peelable substrate 2 of laminate (A) before or after bonding (A) and laminate (B) It relates to a method for producing an optical laminate, characterized in that goes through the respective steps of the third step of peeling off at least.

A third aspect of the present invention relates to a method for producing an optical laminate according to the above, wherein the liquid crystal material layer is composed of a liquid crystal material layer in which a nematic alignment formed by a liquid crystal material exhibiting optically positive uniaxiality in a liquid crystal state is immobilized. will be.

The 4th of this invention relates to the elliptical polarizing plate which consists of an optical laminated body obtained by the above-mentioned manufacturing method.

5th of this invention is related with the circular polarizing plate which consists of an optical laminated body obtained by the above-mentioned manufacturing method.

A sixth aspect of the present invention relates to a liquid crystal display device including at least the elliptical polarizing plate or the circular polarizing plate described above.

In addition, in the said description, "/" shows the interface of each layer, and shall be described likewise below.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

The liquid crystal material layer in which the alignment of the liquid crystal used in the present invention is immobilized is a layer immobilized by using a means for immobilizing the liquid crystal material in the alignment state. As a means for immobilization, the liquid crystal material layer is rapidly cooled from the alignment state in the vitrified state. And a method of immobilizing a low molecular or polymeric liquid crystal material having a reactive functional group and then immobilizing the functional group by reacting (curing and crosslinking).

Examples of the reactive functional group include vinyl group, (meth) acryloyl group, vinyloxy group, epoxy group, oxetanyl group, carboxyl group, hydroxyl group, amino group, isocyanate group, acid anhydride, and the like. Is done.

Although the liquid crystal substance which can be used for a liquid crystal material layer can be selected from a wide range regardless of a low molecular liquid crystal substance and a high molecular liquid crystal substance by the use and the manufacturing method which a liquid crystal film aims at, a high molecular liquid crystal substance is preferable. In addition, the molecular shape of a liquid crystal substance may be a rod shape or a disk shape. For example, a discotic liquid crystal compound exhibiting discotic nematic liquid crystal can also be used.

Examples of the liquid crystal phase of the liquid crystal material layer before immobilization include a nematic phase, a torsional nematic phase, a cholesteric phase, a hybrid nematic phase, a hybrid torsional nematic phase, a discotic nematic phase, and a smectic phase.

As the polymer liquid crystal substance, various main chain polymer liquid crystal substances, side chain polymer liquid crystal substances, or a mixture thereof can be used. Examples of the main chain polymer liquid crystal material include polyester, polyamide, polycarbonate, polyimide, polyurethane, polybenzimidazole, polybenzoxazole, polybenzthiazole, polyazomethine and polyesteramide. Polymeric liquid crystal substances, such as polyester carbonate type and polyester imide type, or these mixture etc. are mentioned. In addition, the side chain type polymer liquid crystal substance has a skeleton having a linear or cyclic structure such as polyacrylate, polymethacrylate, polyvinyl, polysiloxane, polyether, polymeronate, polyester, or the like. Examples thereof include a polymer liquid crystal material having a mesogenic group bonded as a side chain to the material, or a mixture thereof. Among these, polyester system of a main chain type | mold polymer liquid crystal substance is preferable from synthesis | combination, the ease of an orientation, etc.

As the low molecular liquid crystal substance, saturated benzene carboxylic acids, unsaturated benzene carboxylic acids, biphenyl carboxylic acids, aromatic oxy carboxylic acids, shipbases, bis azomethine compounds, azo compounds, azoxy compounds, cyclohexane esters The compound etc. which showed the liquid crystallinity which introduce | transduced the said reactive functional group in the terminal, such as a compound and a sterol compound, the composition which added the crosslinking | crosslinked compound to the compound which shows liquid crystallinity among the said compounds are mentioned. Moreover, as a discotic liquid crystal compound, a triphenylene system, a toxen system, etc. are mentioned.

Moreover, you may mix | blend the various compound which has a functional group or site | part which can react with a heat or a light crosslinking reaction, etc. in a liquid crystal substance in the range which does not prevent liquid crystalline expression. As a functional group which can carry out crosslinking reaction, the various reactive functional groups mentioned above are mentioned.

The liquid crystal material layer in which the orientation of the liquid crystal is immobilized is a method of applying a liquid crystal material or a composition containing various compounds added as necessary onto the alignment substrate in a molten state, or applying a solution of the composition onto the alignment substrate. And a coating film formed on the alignment substrate by drying and heat treatment (alignment of the liquid crystal) to fix the above-described orientation such as light irradiation and / or heat treatment (polymerization and crosslinking) as necessary. It is formed by fixing the orientation using.

The solvent used for preparation of the solution is not particularly limited as long as it is a solvent that can dissolve the liquid crystal substance and the composition used in the present invention and can be removed by appropriate conditions. Generally, acetone, methyl ethyl ketone, and isophorone are used. Ketones, such as butoxyethyl alcohol, hexyloxyethyl alcohol, ether alcohols such as methoxy-2-propanol, glycol ethers such as ethylene glycol dimethyl ether and diethylene glycol dimethyl ether, ethyl acetate and methoxy propylpropyl , Esters such as ethyl lactate, phenols such as phenol and chlorophenol, amides such as N, N-dimethylformamide, N, N-dimethylacetamide, and N-methylpyrrolidone, chloroform, tetrachloroethane and dichloro Halogenated hydrocarbons, such as benzene, These mixed systems are used preferably. Moreover, in order to form a uniform coating film on an orientation board | substrate, you may add surfactant, an antifoamer, a leveling agent, etc. to a solution. Moreover, dichroic dye, normal dye, pigment, etc. can also be added in the range which does not prevent liquid crystalline expression for coloring purpose.

About the coating method, if it is a method of ensuring the uniformity of a coating film, a well-known method can be employ | adopted without being specifically limited. For example, the roll coat method, the die coat method, the dip coat method, the curtain coat method, the spin coat method, etc. are mentioned. After coating, a solvent removal (drying) step may be added by a method such as a heater or hot air blowing. The film thickness in the dry state of the apply | coated film | membrane is 0.1 micrometer-50 micrometers, Preferably it is 0.2 micrometer-20 micrometers, More preferably, it is 0.3 micrometer-10 micrometers. Outside this range, the optical performance of the obtained liquid crystal material layer is insufficient, or the orientation of the liquid crystal material is insufficient.

Subsequently, if necessary, after the alignment of the liquid crystal is formed by heat treatment or the like, the alignment is fixed. Heat treatment orientates a liquid crystal by the self-orientation performance which a liquid crystal substance originally has by heating in liquid crystal phase expression temperature range. As conditions of heat processing, since optimal conditions and a limit value differ with liquid crystal phase behavior temperature (transition temperature) of the liquid crystal substance to be used, although it cannot say uniformly, it is 10-300 degreeC normally, Preferably it is the range of 30-250 degreeC. At too low a temperature, the alignment of the liquid crystal may not proceed sufficiently, and at a high temperature, the liquid crystal material may decompose or adversely affect the alignment substrate. The heat treatment time is usually in the range of 3 seconds to 60 minutes, preferably 10 seconds to 30 minutes. In the heat treatment time shorter than 3 seconds, there is a possibility that the alignment of the liquid crystal may not be completed sufficiently, and in the heat treatment time exceeding 60 minutes, the productivity is extremely deteriorated. After the alignment of the liquid crystal is completed by heat treatment or the like, the liquid crystal material is immobilized using a means suitable for the liquid crystal material using the liquid crystal material layer on the alignment substrate in an intact state.

Examples of the alignment substrate include polyimide, polyamide, polyamideimide, polyphenylene sulfide, polyphenylene oxide, polyether ketone, polyether ether ketone, polyether sulfone, polysulfone, polyethylene terephthalate, polyethylene naphthalate, and polyaryl ray. Films such as sodium, triacetyl cellulose, epoxy resins, and phenol resins can be exemplified.

Although these films show sufficient orientation performance with respect to the liquid crystal substance used for this invention, even if it does not perform the process for expressing orientation performance newly depending on a manufacturing method, they have insufficient orientation performance or do not show orientation performance, etc. In the case of, an alignment film made of a known alignment agent such as polyimide, polyvinyl alcohol, a silane coupling agent, or the like is formed on a film subjected to a so-called rubbing treatment, in which these films are stretched under appropriate heating and wiped in one direction with a rayon cloth or the like. It may provide a rubbing process, a film in which orientation performance is exhibited by inclination-deposition process, such as silicon oxide, or a combination of these suitably.

Moreover, as an orientation board | substrate, metal plates, such as aluminum, iron, copper, etc. which provided many regular fine grooves in the surface, various glass plates, etc. can also be used.

Here, it is not specifically limited as the orientation processing direction of an orientation substrate film, It can select suitably by performing each said process in arbitrary directions. In particular, when handling the liquid crystal film formed on an elongate orientation board | substrate, it is preferable to select a predetermined angle with respect to MD direction of the said elongate continuous film, and to perform an orientation process to a diagonal direction as needed. By the alignment treatment in a predetermined angular direction, when laminating the liquid crystal film in an axial arrangement capable of exhibiting suitable optical properties, bonding (also called roll-to-roll bonding) in the state where MD of the long film is aligned is possible or so-called It is very advantageous from the point of obtaining high efficiency.

The liquid crystal material layer formed on the alignment substrate is then adhered to the releasable substrate or the releasable substrate 1 via the adhesive layer or the adhesive layer 1.

As this adhesive layer or adhesive layer 1, it has sufficient adhesive force with respect to a liquid crystal material layer and a re-peelable board | substrate or re-peelable board | substrate 1, and it is possible to peel a re-peelable board | substrate in a subsequent process, and a liquid crystal material There is no restriction | limiting in particular if it does not impair the optical characteristic of a layer. Moreover, the same adhesive agent can be used also as the adhesive bond layer 2 at the time of transferring to the removable board | substrate 2 mentioned later.

Examples of the adhesives include acrylic resins, methacryl resins, epoxy resins, ethylene-vinyl acetate copolymers, rubbers, urethanes, polyvinyl ethers, and mixtures thereof, thermosetting and / or photocuring, and electron beam curing. Reactive thing can be mentioned as an example. These adhesives also include those having a function as a transparent protective layer protecting the liquid crystal material layer. Moreover, an adhesive can also be used as said adhesive agent. In addition, there is no limitation in that the adhesive bond layer 1 and the adhesive bond layer 2 are the same or different.

Since the reaction (curing) conditions of the reactive object change depending on the components constituting the adhesive and the conditions such as viscosity and reaction temperature, the appropriate conditions may be selected and performed. For example, in the case of the photocuring type, various known photoinitiators are preferably added, and light from a light source such as a metal halide lamp, a high pressure mercury lamp, a low pressure mercury lamp, a xenon lamp, an arc lamp, a laser, a synchrotron radiation light source, The reaction may be performed. As irradiation amount per unit area (1 square centimeter), it is a range of 1-2000 mJ normally, Preferably it is 10-1000 mJ as integrated irradiation amount. However, the case where the absorption region of a photoinitiator and the spectra of a light source differ remarkably, or the case where the reactive compound itself has the absorption ability of a light source wavelength does not fall in this range. In these cases, methods, such as using a suitable photosensitizer or two or more types of photoinitiators with different absorption wavelengths, may be used. The acceleration voltage in the case of an electron beam curing type is 10 kV-200 kV normally, Preferably it is 50 kV-100 kV.

As mentioned above, although the thickness of an adhesive bond layer differs according to the component which comprises an adhesive agent, the strength of an adhesive agent, use temperature, etc., it is 1-50 micrometers normally, Preferably it is 2-30 micrometers, More preferably, it is 3-10 micrometers. Outside of this range, it is not preferable because the adhesive strength is insufficient, or there is a bleeding from the end.

Moreover, these adhesive layers can also add various microparticles | fine-particles etc. and a surface modifier for the purpose of controlling an optical characteristic or controlling peelability and erosion of a board | substrate in the range which does not impair the characteristic.

As said microparticles | fine-particles, the microparticles | fine-particles which differ in refractive index from the compound which comprises an adhesive agent, electroconductive microparticles | fine-particles for antistatic performance improvement, microparticles | fine-particles for abrasion resistance improvement, etc. can be illustrated, without damaging transparency, More specifically, fine silica, fine alumina , ITO (Indium Tin Oxide) fine particles, silver fine particles, various synthetic resin fine particles and the like.

The surface modifier is not particularly limited as long as it has good compatibility with the adhesive and does not affect the curing property of the adhesive or the optical performance after curing, and is not limited to ionic and nonionic water-soluble surfactants, oil-soluble surfactants, polymer surfactants, Organometallic surfactants such as fluorine-based surfactants and silicones, reactive surfactants and the like can be used. In particular, fluorine-based surfactants such as perfluoroalkyl compounds, perfluoropolyether compounds, or organometallic surfactants such as silicones are particularly preferred because they have a large surface modification effect. The amount of the surface modifier added is preferably in the range of 0.01 to 10% by weight, more preferably 0.05 to 5% by weight, still more preferably 0.1 to 3% by weight based on the adhesive. If the added amount is too small than this range, the effect of addition becomes insufficient. On the other hand, if the added amount is too large, there is a possibility that adverse effects such as excessively low adhesive strength may occur. Moreover, surface modifiers may be used independently and may use multiple types together as needed.

Moreover, you may mix | blend various additives, such as antioxidant and a ultraviolet absorber, in the range which does not impair the effect of this invention.

Examples of the releasable substrate used in the present invention include olefin resins such as polyethylene, polypropylene, and 4-methylpentene-1 resin, polyamide, polyimide, polyamideimide, polyetherimide, polyether ketone, and polyether ether ketone. , Polyether sulfone, polyketone sulfide, polysulfone, polystyrene, polyphenylene sulfide, polyphenylene oxide, polyethylene terephthalate, polybutylene terephthalate, polyarylate, polyacetal, uniaxially stretched polyester, polycarbonate, poly Films such as vinyl alcohol, polymethyl methacrylate, polyarylate, amorphous polyolefin, norbornene-based resin, triacetyl cellulose, or epoxy resin can be used.

In particular, as a transparent and optically isotropic film excellent in inspecting optical defects, 4-methylpentene-1, polymethyl methacrylate, polystyrene, polycarbonate, polyether sulfone, polyarylate, amorphous polyolefin, norbornene-based Each film, such as resin, triacetyl cellulose, or an epoxy resin, can be illustrated.

These plastic films can be coated with silicon on their surface in advance in order to have appropriate re-peelability, or an organic thin film or an inorganic thin film can be formed. Moreover, for the same purpose, a chemical treatment such as a saponification treatment may be performed on the surface of the plastic film, or a physical treatment such as corona treatment may be performed.

Moreover, in order to adjust the peelability of a repeelable board | substrate, you may make it contain a lubricant and a surface modifier to said plastic film. As said lubricant, there is no restriction | limiting in particular in a kind and addition amount as long as it is a range which does not adversely affect the testability and peelability of an optical defect. Specific examples of the lubricant include fine silica, fine alumina, and the like, and the index of the added amount may be 50% or less, preferably 30% or less, of the haze value of the releasable substrate. When the addition amount is too small, the addition effect is not confirmed. On the other hand, when the addition amount is too large, the inspectability of the optical defect deteriorates, which is not preferable.

Moreover, you may contain other well-known various additives, for example, anti-broken agent, antioxidant, antistatic agent, heat stabilizer, impact resistance improving agent, etc. as needed.

Regarding the peeling force of the releasable substrate, even a releasable substrate made of the same material varies depending on the manufacturing method and the surface state and the wettability with the adhesive used, but cannot be determined uniformly. The peel force at (180 ° peel, peel rate 30 cm / min, measured at room temperature) is usually 0.38 to 12 N / m, preferably 0.38 to 8.0 N / m. If the peeling force is lower than this value, the peeling force is too low when the liquid crystal material layer on the alignment substrate is bonded to the releasable substrate and then the peeling force is too low, so that floating is found on the releasable substrate, which is good at the desired interface. If the peeling state is not obtained and the transfer of the liquid crystal material layer to the releasable substrate is insufficient, and if the peeling force is too high, breakage of the liquid crystal material layer when peeling the releasable substrate or an interface with a desired layer. It is not preferable because it cannot carry out peeling off.

Moreover, the thickness of a re-peelable board | substrate may also affect peelability, Preferably it is 16-100 micrometers, Especially preferably, 25-50 micrometers is good. If the thickness is too thick, the peeling point may not be stable and the peelability may deteriorate. On the other hand, if the thickness is too thin, the mechanical strength of the film may not be maintained, and thus there may be a problem of rupture during manufacture.

Examples of the polymer stretched film used in the present invention include uniaxial cellulose, polycarbonate, polyarylate, polysulfone, polyvinyl alcohol (PVA), polyacryl, polyethersulfone, cyclic polyolefin, or the like. A biaxially stretched retardation film can be illustrated. Among them, uniaxially oriented films of cyclic polyolefins such as polycarbonate and norbornene are preferred from the viewpoint of ease of manufacture, film uniformity, or optical properties.

Here, it does not specifically limit as a direction of extending | stretching, It can select suitably by performing in arbitrary directions. In particular, in the case of handling a long polymeric stretched film, it is preferable to be stretched (laterally stretched) in an oblique direction (tilt stretch) or a TD direction at a predetermined angle with respect to the MD direction of the long continuous film. When the stretched film is laminated in a axial arrangement capable of exhibiting the most suitable optical properties with a liquid crystal film or a polarizing plate by stretching the film in a direction of a predetermined angle, bonding (so-called roll-to-roll bonding) in a state where the MD of the long film is aligned It is very advantageous in that it becomes possible or the efficiency of obtaining a product becomes high.

The polarizing plate used in the present invention is not particularly limited as long as the object of the present invention can be achieved, and a polarizing plate usually used in a liquid crystal display device can be appropriately used. desirable. Specifically, urea and / or dichroic pigments are adsorbed and stretched on a hydrophilic polymer film made of a PVA-based polarizing film such as polyvinyl alcohol (PVA) or partial acetalized PVA, a partial saponification of an ethylene-vinyl acetate copolymer, or the like. The polarizing film etc. which consist of a polyene oriented film, such as a polarizing film, the dehydration process of PVA, and the dehydrochlorination process of polyvinyl chloride, etc. can be used. Moreover, a reflective polarizing film can also be used.

The said polarizing plate may be used independently of a polarizing film, and the transparent protective layer etc. may be provided in the one side or both sides of a polarizing film for the purpose of strength improvement, moisture resistance improvement, heat resistance improvement, etc. As a transparent protective layer, what laminated | stacked transparent plastics, such as polyester and triacetyl cellulose directly or via an adhesive bond layer, the coating layer of resin, photocurable resin layers, such as an acryl-type and an epoxy type, etc. are mentioned. When coating these transparent protective layers on both surfaces of a polarizing film, the same transparent protective layer may be provided on both surfaces, and another transparent protective layer may be provided.

Next, the manufacturing method of the optical laminated body of this invention is demonstrated in detail.

Although it does not specifically limit as a manufacturing method of a liquid crystal material layer, For example, it can manufacture by the following method 1 and method 2.

Method 1

A coating film of the liquid crystal material is formed on the alignment substrate by an appropriate method, the solvent and the like are removed as necessary to complete the alignment of the liquid crystal by heating or the like, and the alignment of the liquid crystal material layer is fixed by means suitable for the used liquid crystal material. Subsequently, an adhesive layer is formed on the liquid crystal material layer in which the alignment is immobilized, the liquid crystal material layer and the releasable substrate are brought into close contact with each other via the adhesive layer, and then the adhesive layer is reacted (cured) as necessary. Peel off.

In this way, the alignment-immobilized liquid crystal material layer can be transferred to the releasable substrate. Thus, a liquid crystal material layer adhered to the releasable substrate via an adhesive layer can be obtained.

The liquid crystal material layer thus obtained may be provided with a transparent protective layer on the liquid crystal material layer exposed for the surface protection of the liquid crystal material layer or by bonding a surface protective film. Here, as a transparent protective layer, you may select from the adhesive agent mentioned above.

That is, as a layer structure of the liquid crystal material layer (it is adhesive agent (A)) formed on the re-peelable board | substrate of this invention via the adhesive bond layer,

① Re-peelable substrate / adhesive layer (1) / liquid crystal material layer

② Re-peelable substrate / adhesive layer (1) / liquid crystal material layer / adhesive layer (2)

Etc. can be mentioned. In addition, in the said description, "/" shows the interface of each layer, and shall be described likewise below.

Method 2

A coating film of the liquid crystal material is formed on the alignment substrate by an appropriate method, the solvent and the like are removed as necessary to complete the alignment of the liquid crystal by heating or the like, and the alignment of the liquid crystal material layer is fixed by means suitable for the used liquid crystal material. Subsequently, the adhesive layer 1 is formed on the liquid crystal material layer in which the orientation is fixed, the liquid crystal material layer and the releasable substrate 1 are brought into close contact with each other via the adhesive layer 1, and then the adhesive layer ( After 1) is reacted (cured), the alignment substrate is peeled off. Subsequently, the adhesive layer 1 formed by adhering the re-peelable substrate 2 and the liquid crystal material layer via the adhesive layer 2, peeling the re-peelable substrate 1 and transferring to the re-peelable substrate 2. ), The laminated body A which consists of a liquid-crystal material layer / adhesive layer 2 / re-peelable board | substrate 2 can be obtained.

The laminated body (A) thus obtained may be further provided with a transparent protective layer or may be bonded to a surface protective film.

Subsequently, the lamination method of the optical laminated body of this invention is demonstrated.

The said laminated body (A) is manufactured as a 1st process.

Subsequently, as a 2nd process, a polymer stretched film and a polarizing plate are bonded together through an adhesive and an adhesive agent (adhesive agent or adhesive agent) layer, and the laminated body (B) which consists of a polarizing plate / adhesive agent layer / polymer stretched film is obtained.

Subsequently, as a 3rd process, this laminated body (B) and laminated body (A) are bonded together through an adhesive and an adhesive bond layer, and the remaining re-peelable board | substrate or re-peelable board | substrate 2 is peeled off, and the optical of this invention is carried out. A laminate can be obtained. Here, joining of the said laminated bodies may be bonded after peeling off the repeelable board | substrate of the laminated body A, and may be peeled off from the laminated body A after rebonding the board | substrate which remains after joining.

By at least going through such a process, the optical laminated body of this invention of the following structures can be obtained, for example.

① Polarizing plate / adhesive (adhesive) layer / polymer stretched film / adhesive (adhesive) layer / liquid crystal material layer / adhesive layer

② Polarizing plate / adhesive (adhesive) layer / polymer stretched film / adhesive (adhesive) layer / adhesive layer / liquid crystal material layer

③ Polarizing plate / adhesive (adhesive) layer / polymer stretched film / adhesive (adhesive) layer / adhesive layer / liquid crystal material layer / adhesive layer

④ Polarizing plate / adhesive (adhesive) layer / polymer stretched film / adhesive (adhesive) layer / adhesive layer / liquid crystal material layer / adhesive layer

In the present invention, it is also possible to laminate a plurality of liquid crystal material layers by repeatedly laminating a liquid crystal material layer having an orientation fixed on the alignment substrate or a liquid crystal material layer transferred onto a re-peelable substrate through an adhesive and an adhesive layer. .

Moreover, in the manufacturing process of this invention, in the form which an orientation board | substrate or a repeelable board | substrate remains on one surface, the adhesive with a release film is bonded to the opposite surface of the said orientation board | substrate, or the opposite surface of the said peelable board | substrate, and said By peeling an orientation board | substrate or a re peelable board | substrate, the release film of an adhesive can be handled as a new re peelable support substrate. By using this method, the pressure-sensitive adhesive can be used as an adhesive for laminating the optical adhesive of the present invention or for laminating with a liquid crystal cell or other optical member, and can also invert the bonding surface up and down arbitrarily. The degree of freedom is further expanded.

Moreover, in this invention, it is also possible to form a release layer between a liquid crystal material layer and another layer by using the releasable board | substrate which previously formed the release layer which can peel from the said board | substrate on the removable board | substrate surface. By forming a release layer, the stress blocking effect for suppressing the external appearance change (for example, wave) of the liquid crystal material layer of a thin film at the time of manufacture or an environmental test can be acquired. Moreover, as a mold release layer, although not specifically limited, an optically isotropic transparent layer is preferable, For example, polymers, such as an acryl type, methacryl type, a nitrocellulose type, an epoxy type compound, and a mixture thereof are mentioned. As a film thickness of a release layer, it is 0.3 micrometer or more and 40 micrometers or less, Preferably it is 0.5 micrometer or more and 10 micrometers or less, A glass transition point (Tg) is an optically isotropic transparent layer of 20 degreeC or more, Preferably it is 50 degreeC or more, A liquid crystal substance There is no particular limitation on the material unless the optical properties of the layer are significantly impaired. The film thickness and the glass transition point are not preferable because the effect thereof is insufficient, or the film thickness is not complied with, which is a part of the object of the present invention.

In addition, the release layer may control material properties by partial crosslinking by addition of a crosslinking component, addition of a plasticizer, addition of a lubricant, and the like.

Moreover, although it does not specifically limit about the formation method of a release layer, For example, application | coating and extrusion of the material used as a release layer which has the said thickness film in advance on re-peelable substrate films, such as polyethylene, a polypropylene, a polyethylene terephthalate, etc. The transfer method which forms by the method of the following, adhere | attaches this layer through an adhesive, an adhesive bond layer, or a transparent protective layer, and peels a re-peelable substrate film after that is mentioned.

In addition to the polarizing plate and the liquid crystal material layer, the optical laminate of the present invention may include one or more layers of an antireflection layer, an antiglare layer, a hard coat layer, and a light diffusion layer. The adhesive or the like used for bonding or bonding to the polarizing plate is not particularly limited so long as it is an optical grade, and for example, a suitable one can be used from the adhesive described above.

The total thickness of the optical laminated body of this invention manufactured as mentioned above is 450 micrometers or less, Preferably it is 350 micrometers or less, More preferably, it is 300 micrometers or less. Outside this range, it is not preferable because it does not comply with the well-known thin film, which is one of the objects of the present invention.

The optical laminated body of this invention can function as a compensation member, an elliptical polarizing plate, and a circular polarizing plate of various liquid crystal display devices according to the optical parameter of a liquid crystal material layer.

That is, since the liquid crystal material layer which the liquid crystal material layer which comprises an optical adhesive fixed the nematic orientation and the torsional nematic orientation for example functions as a phase difference plate, the optical laminated body of this invention which makes the said liquid crystal material layer a structural member Can be used as a compensation plate of transmissive or reflective liquid crystal display devices such as STN type, TN type, OCB type, and HAN type.

In addition, the liquid crystal material layer in which the nematic hybrid orientation is immobilized can be used as a retardation film or a wave plate by using a delay when viewed from the front, and asymmetry due to the direction of the retardation value (the inclination of the molecular axis in the film thickness direction). Can be used also for a viewing angle improvement member of a TN type liquid crystal display device.

Moreover, the liquid crystal material layer which has a 1/4 wavelength plate function can be used as a circularly polarizing plate, a reflective liquid crystal display device, an antireflection filter of an EL display device, etc. by combining with a polarizing plate like this invention. In particular, in order to obtain a broadband quarter wave plate which functions over a wide band in the visible light region, the birefringent light of a quarter wave plate having a phase difference of birefringent light at 550 nm monochromatic light at approximately 1/4 wavelength and a monochromatic light at 550 nm It is generally known that lamination of 1/2 wave plates having a phase difference of about 1/2 wavelength in the state where their slow axes intersect is effective, and is widely used in reflection type liquid crystal display devices and the like. That is, using the technique of obtaining a thin optical laminated body like the manufacturing method of this invention, it becomes possible to obtain the thin broadband 1/4 wavelength plate which was difficult only with the conventional polymer stretched film. Here, the delay value of the quarter wave plate is usually in the range of 70 nm to 180 nm, preferably 90 nm to 160 nm, and particularly preferably 120 nm to 150 nm. In addition, the delay of the half wave plate is usually in the range of 180 nm to 320 nm, preferably 200 nm to 300 nm, particularly preferably 220 nm to 280 nm. When the delay ranges of the quarter wave plate and the half wave plate deviate from the above, there is a possibility that unnecessary coloring occurs in the liquid crystal display device. In addition, a delay value represents the product of birefringence (DELTA) n and a film thickness (d).

Moreover, in the optical laminated body of this invention, when the liquid crystal material layer which comprises the said laminated body fixes cholesteric orientation and smetic orientation, the polarizing reflection film for brightness improvement, a reflective color filter, and selective reflection It can use for the various anti-counterfeiting element, the decorative film, etc. which utilized the color change of the reflected light by the time due to performance.

Hereinafter, although an Example and a comparative example demonstrate manufacture of a circularly polarizing plate as an example in more detail, this invention is not limited to these. In addition, the delay (product of birefringence (DELTA) n and film thickness d) in a present Example is a value in wavelength 550nm unless there is a notice.

[Preparation Example]

270 degreeC under nitrogen atmosphere using 50 mmol of telephthalic acid, 50 mmol of 2, 6- naphthalenedicarboxylic acid, 40 mmol of methylhydroquinone diacetate, 60 mmol of catechol diacetate, and 60 mg of N-methylimidazole. Polycondensation was carried out for 12 hours. Next, the obtained reaction product was dissolved in tetrachloroethane, reprecipitated with methanol, and purified to obtain 14.6 g of liquid crystalline polyester. The logarithmic viscosity (phenol / tetrachloroethane (6/4 weight ratio) mixed solvent: 30 degreeC) of this liquid crystalline polyester (polymer (1)) has a nematic phase as 0.16 dl / g and a liquid crystal phase, and isotropic-liquid crystal The phase transition temperature was 250 degreeC or more, and the glass transition temperature by differential scanning calorimeter (DSC) was 112 degreeC.

20 g of polymer (1) was dissolved in 80 g of N-methyl-2-pyrrolidone to prepare a solution. This solution was applied to a polyimide film (trade name "Kapton" manufactured by DuPont) subjected to a rubbing treatment with a rayon cloth, and dried to remove the solvent, followed by heat treatment at 210 ° C for 20 minutes to form a nematic alignment structure. After the heat treatment, the mixture was cooled to room temperature to fix the nematic alignment structure and to obtain a uniformly oriented liquid crystal material layer having an actual film thickness of 1.4 mu m on the polyimide film. Actual film thickness was measured using a tactile film thickness meter.

EXAMPLE

A UV curable adhesive (UV-3400, manufactured by Dong-A Synthetic Co., Ltd.) commercially available on the liquid crystal material layer (surface on the opposite side to the polyimide film) obtained in the preparation example was applied as the adhesive layer (1). On top of this, a polyethylene terephthalate (PET) film (1; S10, manufactured by Toray Industries, Ltd.), which is a releasable substrate having a thickness of 25 µm, was laminated, and the adhesive layer 1 was cured by UV irradiation at about 600 mJ. . Thereafter, the liquid crystal material layer is peeled off on the PET film 1 as a releasable substrate by peeling the polyimide film from the laminate in which the PET film 1, the adhesive layer 1, the liquid crystal material layer, and the polyimide film are integrated. It transferred to and obtained the adhesive agent (A) which consists of PET film (1) / adhesive layer (1) / liquid crystal material layer. Here, the laminated body (A; (DELTA) nd) at the time of peeling the PET film 1 was 140 nm.

Next, a 25-micrometer-thick adhesive layer previously formed on the siliconization PET film was bonded to one surface of the uniaxially stretched polycarbonate film (60 micrometers in thickness, (DELTA) nd270 nm) commercially available. Subsequently, a polarizing plate (thickness of about 180 µm; SQW-862, manufactured by Sumitomo Chemical Co., Ltd.), which had a pressure-sensitive adhesive layer having a thickness of 25 µm formed on one side in advance, was bonded to the surface where the pressure-sensitive adhesive of the film was not bonded. The laminated body (B) which consists of a polarizing plate / adhesive layer / polycarbonate film / adhesive layer / silicone process PET film was obtained.

The silicone-treated PET of the laminate was peeled off and bonded to the liquid crystal material layer surface of the laminate (A) to form a polarizing plate / adhesive layer / polycarbonate film / adhesive layer / liquid crystal material layer / adhesive layer (1) / PET film (1) The laminated body of was obtained. The circular polarizing plate of this invention was obtained by peeling the PET film 1 of the said laminated body. The total thickness of the circular polarizing plate was 297 μm.

Second Embodiment

The circular polarizing plate obtained in Example 1 was bonded to the upper and lower liquid crystal cells of a commercially available transflective TFT liquid crystal display using an adhesive and evaluated for display characteristics. It was a sign. In addition, when the display device was subjected to two types of durability tests of (1) 60 ° C., 90% RH for 500 hours, (2) 80 ° C., and 500 hours in dry, no abnormalities in appearance such as peeling and cracking were observed at all.

Third Embodiment

A UV curable adhesive (UV-3400, manufactured by Dong-A Synthetic Co., Ltd.) commercially available on the liquid crystal material layer (surface on the opposite side to the polyimide film) obtained in the preparation example was applied as the adhesive layer (1). On top of this, a polyethylene terephthalate (PET) film (1; S10, manufactured by Toray Industries, Ltd.), which is a releasable substrate having a thickness of 25 µm, was laminated, and the adhesive layer 1 was cured by UV irradiation at about 600 mJ. . Thereafter, the liquid crystal material layer is peeled off on the PET film 1, which is a releasable substrate, by peeling the polyimide film from the laminate in which the PET film 1, the adhesive layer 1, the liquid crystal material layer, and the polyimide film are integrated. Killed. Next, a UV curable adhesive (UV-3400) commercially available on the liquid crystal material layer was applied as the adhesive layer 2 to a thickness of 5 mu m, and thereon a PET film 2 which is a re-peelable substrate having a thickness of 25 mu m; S10) was laminated to cure the adhesive layer 2 by UV irradiation of about 600 mJ. Then, the laminated body (A) which consists of an adhesive bond layer (1) / liquid crystal material layer / adhesive bond layer (2) / PET film (2) was obtained by peeling PET film (1). Here, the laminated body (A; (DELTA) nd) at the time of peeling the PET film 2 was 140 nm.

Next, the adhesive layer of thickness 25micrometer previously formed on the siliconization PET film was bonded to one surface of the uniaxially stretched polycarbonate film (60 micrometers in thickness, (DELTA) nd270 nm) commercially available. Subsequently, a polarizing plate (thickness of about 180 µm; SQW-862, manufactured by Sumitomo Chemical Co., Ltd.), which had a pressure-sensitive adhesive layer having a thickness of 25 µm formed on one side in advance, was bonded to the surface where the pressure-sensitive adhesive of the film was not bonded. The laminated body (B) which consists of a polarizing plate / adhesive layer / polycarbonate film / adhesive layer / silicone process PET film was obtained.

The silicone-treated PET of the laminate was peeled off and bonded to the laminate A to form a polarizing plate / adhesive layer / polycarbonate film / adhesive layer / adhesive layer (1) / liquid crystal material layer / adhesive layer (2) / PET film ( After obtaining the laminated body of 2), the circular polarizing plate of this invention was obtained by peeling off PET film (2). The total thickness of the circular polarizing plate was 300 µm.

[Example 4]

When the circularly polarizing plate obtained in the third embodiment was bonded to the upper and lower liquid crystal cells of a commercially available semi-transmissive TFT liquid crystal display using an adhesive, and the display characteristics were evaluated, the display of any circular polarizing plate was satisfactory in both the reflection mode and the transmission mode. It was. In addition, when the display device was subjected to two types of durability tests of (1) 60 ° C., 90% RH for 500 hours, (2) 80 ° C., and 500 hours in dry, no abnormalities in appearance such as peeling and cracking were observed at all.

[First Comparative Example]

A commercially available uniaxially stretched polycarbonate film (1; 60 μm thick, Δnd 135 nm) and a polycarbonate film (2; 60 μm thick, Δnd 270 nm) were bonded together using a 25 μm adhesive to form a polycarbonate film ( The laminated body which consists of 1) / adhesive layer / polycarbonate film (2) was obtained.

On the polycarbonate (2) surface of the laminate, a polarizing plate (about 180 μm thick; SQW-862 manufactured by Sumitomo Chemical Co., Ltd. The circularly polarizing plate which consists of / polycarbonate film (2) / adhesive layer / polycarbonate film (1) was obtained. The total thickness of the circular polarizer was thick at 350 mu m.

Second Comparative Example

A pressure-sensitive adhesive layer having a thickness of 25 μm formed on a silicone-treated PET film in advance was bonded to one side of a commercially available uniaxially stretched norbornene-based film (1; 80 μm in thickness, Δnd 275 nm; atton manufactured by JSR Co., Ltd.). . Subsequently, a polarizing plate (thickness of about 180 µm; SQW-862, manufactured by Sumitomo Chemical Co., Ltd.), which had a pressure-sensitive adhesive layer having a thickness of 25 µm formed on one side in advance, was bonded to the surface where the pressure-sensitive adhesive of the film was not bonded. The laminated body which consists of a polarizing plate / adhesive layer / norbornene-type film (1) / adhesive layer / silicone process PET film was obtained.

The polarizing plate / adhesive layer / norm is peeled off by peeling the silicone-treated PET film of the said laminated body, and bonding the commercially available uniaxially-stretched norbornene-type film (2; 80 micrometers in thickness, (DELTA) nd 130 nm; Atone made by JSR Corporation). The circularly polarizing plate which consists of a bonene type film (1) / adhesive layer / norbornene type film (2) was obtained. The total thickness of the circular polarizer was thick at 390 μm.

According to the present invention, it is possible to establish an industrial production method of laminating a liquid crystal material layer without a support substrate film to a polymer stretched film, and to improve the optical properties and greatly reduce the thickness of the optical properties, which was difficult only with a laminate of a conventional polymer stretched film. The new optical laminated body which achieves both of these is obtained, and industrial value is very high.

Claims (7)

(1) After adhering the liquid crystal material layer in which the liquid crystal alignment formed on the alignment substrate is immobilized with the releasable substrate via the adhesive layer, the alignment substrate is peeled off, the liquid crystal material layer is transferred to the releasable substrate, and re-peeled. A first step of obtaining a laminate (A) comprising a substrate / adhesive layer / liquid crystal material layer; (2) a second step of bonding the polymer stretched film and the polarizing plate through an adhesive and an adhesive layer to obtain a laminate (B) comprising a polarizing plate / adhesive (adhesive) layer / polymer stretched film; (3) At least each step of the 3rd process of peeling the re-peelable board | substrate of the laminated body (A) before or after bonding the said laminated body (A) and the laminated body (B) is characterized by the above-mentioned. The manufacturing method of an optical laminated body. (1) After adhering the liquid crystal material layer in which the liquid crystal alignment formed on the alignment substrate is fixed to the re-peelable substrate 1 via the adhesive layer 1, the alignment substrate is peeled off and the liquid crystal material layer is re-peeled substrate. Transfer to (1), and then the re-peelable substrate 2 and the liquid crystal material layer are adhered to each other via the adhesive layer 2 to peel the re-peelable substrate 1, and transferred to the re-peelable substrate 2 1st process of obtaining the laminated body A which consists of the adhesive bond layer 1 / liquid-crystal material layer / adhesive agent 2 / re-peelable board | substrate 2 which are formed, and (2) a second step of bonding the polymer stretched film and the polarizing plate through an adhesive and an adhesive to obtain a laminate (B) comprising a polarizing plate / adhesive (adhesive) layer / polymer stretched film; (3) At least passing through each step of the third step of peeling the re-peelable substrate 2 of the laminate (A) before or after bonding the laminate (A) and the laminate (B). The manufacturing method of the optical laminated body characterized by the above-mentioned. 3. The optical laminate according to claim 1 or 2, wherein the liquid crystal material layer is composed of a liquid crystal material layer in which a nematic alignment formed in a liquid crystal state is immobilized. Manufacturing method. It consists of the optical laminated body obtained by the manufacturing method of Claim 1 or 2, The elliptical polarizing plate characterized by the above-mentioned. It consists of the optical laminated body obtained by the manufacturing method of Claim 1 or 2, The circular polarizing plate characterized by the above-mentioned. The elliptical polarizing plate of Claim 4 is provided, The liquid crystal display device characterized by the above-mentioned. The circular polarizing plate of Claim 5 is provided, The liquid crystal display device characterized by the above-mentioned.