JP2000310711A - Optical laminated body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new diffraction element of which the diffracted rays themselves produce specified polarized light such as circularly polarized light or linearly polarized light. SOLUTION: The optical laminated body is a laminated body which at least comprises a supporting substrate/an adhesive layer/a cholesteric liquid crystal layer/and a protective layer. The cholesteric liquid crystal layer comprises a cholesteric liquid crystal film having a region exhibiting diffractivity in at least a part in the film thickness direction. The protective layer is provided with an ultraviolet ray absorbing property and a hard coatability. The supporting substrate is not an especially limited matter as long as it has a shape of a sheet-like, a film-like or a plate-like matter.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical laminate comprising a novel cholesteric liquid crystal film capable of generating diffracted light having a polarization property.

[0002]

2. Description of the Related Art A diffractive element is a general-purpose optical element that is widely used in the field of spectral optics and the like for the purpose of splitting light and splitting a light beam. Diffraction elements are classified into several types based on their shape.Amplitude type diffraction elements, in which light-transmitting and non-light-transmitting parts are periodically arranged, are phase-type, in which periodic grooves are formed in a highly transparent material. It is usually classified as a diffraction element. Further, they may be classified as a transmission type diffraction element or a reflection type diffraction element according to the direction in which diffracted light is generated.

In the above-described conventional diffraction element, only non-polarized light can be obtained as diffracted light obtained when natural light (non-polarized light) is incident. Polarizing optical instruments such as ellipsometers, which are frequently used in the field of spectroscopy, can only obtain non-polarized light as diffracted light. In general, a method of using diffracted light through a polarizer in order to use only the polarized light component is used.
In this method, there is a problem that about 50% or more of the obtained diffracted light is absorbed by the polarizer, so that the amount of light is reduced by half. For that purpose, it is necessary to prepare a detector having a high sensitivity and a light source having a large amount of light, and the development of a diffraction element in which the diffracted light itself becomes a specific polarized light such as a circularly polarized light or a linearly polarized light has been required.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has succeeded in imparting diffractive power to a partial region of a cholesteric liquid crystal layer by controlling the structure of the liquid crystal layer. More specifically, by using a cholesteric liquid crystal layer provided with a new property of diffractive ability in addition to selective reflection characteristics and circular polarization characteristics peculiar to cholesteric liquid crystals, an optical laminated body that suitably functions as a polarization diffraction element is invented. I came to.

[0005]

That is, the present invention is a laminate comprising at least a support substrate / adhesive layer / cholesteric liquid crystal layer / protective layer, wherein the cholesteric liquid crystal layer has at least partly diffractive ability. The present invention relates to an optical laminate comprising a cholesteric liquid crystal film having a region, wherein a protective layer has an ultraviolet absorbing property and a hard coat property.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be specifically described below. The optical laminate of the present invention comprises at least a support substrate / adhesive layer / cholesteric liquid crystal layer / protective layer. Here, the term “support substrate / adhesive layer / cholesteric liquid crystal layer / protective layer” means a configuration in which a support substrate, an adhesive layer, a cholesteric liquid crystal layer, and a protective layer are laminated in this order.

The support substrate which is a component of the present invention is not particularly limited as long as it has a shape such as a sheet, a film, and a plate. For example, polyimide, polyamide imide, polyamide , Polyether imide, polyether ether ketone, polyether ketone, polyketone sulfide, polyether sulfone, polysulfone, polyphenylene sulfide, polyphenylene oxide, polyvinyl chloride, polystyrene, polypropylene, polymethyl methacrylate, polyethylene terephthalate, polybutylene terephthalate, polyethylene Sheets and sheets of naphthalate, polycarbonate, polyvinyl alcohol, polyacetal, polyarylate, cellulosic plastics, epoxy resin, phenolic resin, etc. Lum or the substrate or paper, paper such as synthetic paper, metal foil, can be appropriately selected from a glass plate or the like. Further, the support substrate may be a substrate having irregularities on its surface.

The adhesive layer, which is a component of the present invention, is not particularly limited, and various conventionally known adhesives, adhesives, hot melt adhesives, heat, light or electron beam-curable reactions can be used. A suitable adhesive or the like can be used as appropriate. Among them, a light or electron beam curing type reactive adhesive is preferably used. Examples of the reactive adhesive include a photopolymer or an electron beam polymerizable prepolymer and / or a monomer, if necessary, other monofunctional or polyfunctional monomers, various polymers, a stabilizer, a photopolymerization initiator, and a sensitizer. And the like can be used.

Specific examples of the prepolymer having photo- or electron beam polymerizability include polyester acrylate, polyester methacrylate, polyurethane acrylate, polyurethane methacrylate, epoxy acrylate, epoxy methacrylate, polyol acrylate, polyol methacrylate and the like. . Examples of the monomer having photo- or electron beam polymerizability include monofunctional acrylate, monofunctional methacrylate, difunctional acrylate, difunctional methacrylate, trifunctional or higher polyfunctional acrylate, and polyfunctional methacrylate. These can also use a commercial item, for example, Aronix (acrylic special monomer, oligomer;
Toagosei Co., Ltd.), Light Ester (Kyoeisha Chemical Co., Ltd.), Biscoat (Osaka Organic Chemical Industry Co., Ltd.)
Etc. can be used.

As the photopolymerization initiator, for example, benzophenone derivatives, acetophenone derivatives, benzoin derivatives, thioxanthones, Michler's ketone, benzyl derivatives, triazine derivatives, acylphosphine oxides, azo compounds and the like can be used. .

The viscosity of the photo- or electron beam-curable reactive adhesive which can be used in the present invention is appropriately selected depending on the processing temperature of the adhesive and cannot be unconditionally determined. ~ 2000 mPa · s, preferably 50
１０００1000 mPa · s, more preferably 100 to 50
0 mPa · s. When the viscosity is lower than 10 mPa · s, it becomes difficult to obtain a desired thickness. 2000mP
If it is higher than a · s, the workability may decrease, which is not desirable. When the viscosity is out of the above range, it is preferable to appropriately adjust the solvent and the monomer ratio to obtain a desired viscosity.

When a photocurable reactive adhesive is used, a known curing method such as a low-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a metal halide lamp, a xenon lamp, or the like is used as a method for curing the adhesive. be able to. Although the exposure amount cannot be determined unconditionally because it differs depending on the type of the reactive adhesive used, it is usually 50 to 2000 mJ.
/ Cm ² , preferably 100 to 1000 mJ / cm ² .

When an electron beam-curable reactive adhesive is used, the method of curing the adhesive is appropriately selected depending on the penetrating power and curing power of the electron beam, and cannot be unconditionally determined. Usually, curing can be carried out by irradiating under an acceleration voltage of 50 to 1000 kV, preferably 100 to 500 kV.

When a hot-melt adhesive is used as the adhesive layer in the present invention, the adhesive is not particularly limited, but the hot-melt working temperature is 80 to 200 ° C., preferably about 100 to 160 ° C. Is desirably used from the viewpoint of workability and the like. Specifically, for example, polyvinyl acetal resins such as ethylene-vinyl acetate copolymer resins, polyester resins, polyurethane resins, polyamide resins, thermoplastic rubbers, polyacrylic resins, polyvinyl alcohol resins, and polyvinyl butyral And those manufactured using petroleum-based resins, terpene-based resins, rosin-based resins, and the like as base resins.

The use of a pressure-sensitive adhesive as the adhesive layer in the present invention is not particularly limited. For example, a rubber-based, acrylic, silicone-, or polyvinyl ether-based pressure-sensitive adhesive can be used. The thickness of the adhesive layer varies depending on the application to be used and its workability and cannot be unconditionally determined, but is usually 0.5 to 50 μm, preferably 1 to 10 μm.

The method for forming the adhesive layer varies depending on the method for producing the optical laminate of the present invention described later. Examples of the method include a roll coating method, a die coating method, a bar coating method, a curtain coating method, an extrusion coating method, and the like. It can be formed on a support substrate or the like using a known method such as a gravure roll coating method, a spray coating method, and a spin coating method.

Next, the cholesteric liquid crystal layer which is a component of the present invention is at least composed of a cholesteric liquid crystal film having a region exhibiting a diffractive ability in a part of the film. Here, the region exhibiting diffractive power is light transmitted through the region or light reflected by the region,
Geometrically, it refers to a region that produces an effect of wrapping around a shadowed portion. In addition, the presence or absence of a region having diffraction ability,
For example, it can be confirmed by the presence or absence of light (higher-order light) emitted at a certain angle other than the light (0th-order light) that enters a laser beam or the like into the region and transmits or reflects linearly. Alternatively, whether or not the region is formed can be confirmed by observing the surface shape or cross-sectional shape of the liquid crystal layer using an atomic force microscope, a transmission electron microscope, or the like.

The cholesteric liquid crystal film is not particularly limited as long as it has a fixed cholesteric orientation and at least a part of the film has a region exhibiting diffractive ability. It can be formed from liquid crystal or a mixture thereof. The region exhibiting diffractive ability may be any region on the film surface and / or inside the film. For example, a region having a part of the film surface (film surface region) and a part of the film inside (film internal region) may be used. Good. In addition, the region may be provided in a plurality of regions of the cholesteric liquid crystal film, for example, a film front and back surface region and a plurality of film inner regions. Further, the region exhibiting diffractive power is not necessarily required to be formed as a layer having a uniform thickness on the film surface or inside, for example, and the region is formed on at least a part of the film surface or inside the film. It should just be. For example, the region having the diffraction power may have a shape such as a desired figure, pictogram, or numeral. Further, when there are a plurality of regions exhibiting diffractive power, it is not necessary that all the regions exhibit the same diffractive power, and each region may exhibit a different diffractive power. The orientation state of the region exhibiting diffractive power is such that the helical axis orientation is not uniformly parallel to the film thickness direction, preferably the helical axis orientation is not uniformly parallel to the film thickness direction, and the helical pitch is the film pitch. It is desirable to form a cholesteric alignment that is not uniformly spaced in the thickness direction. In other regions, a helical structure in which the helical axis orientation is uniformly parallel to the film thickness direction and the helical pitch is uniformly spaced uniformly in the film thickness direction is the same as the normal cholesteric orientation. It is desirable to form. In the present invention, the term "film surface" means a portion of the cholesteric liquid crystal film alone that contacts the outside, and the term "inside of the film" means a portion other than contacting the outside.

In the present invention, any of the above-mentioned cholesteric liquid crystalline films can be used, but from the viewpoint of the film production method, the method of imparting diffractive power, etc., at least a part of the film surface region, preferably the film surface region. A cholesteric liquid crystal film having a region exhibiting diffractive power over the entire surface is suitably used. Also, when one of the film surface regions has a diffractive power region, the optical effect and coloration are slightly different from the front and back of the film, that is, the film surface having the diffractive power region and the opposite film surface. From the viewpoint of the effects and the like, it is possible to select which film surface is to be the protective layer side constituting the optical laminate of the present invention in accordance with the use and the intended function. Further, when the region exhibiting diffractive ability is formed in a layer state, the thickness of the layer (region) exhibiting diffractive ability is usually 50% or less with respect to the thickness of the cholesteric liquid crystal film.
It is desirable to be formed in a layer state having a thickness of preferably 30% or less, more preferably 10% or less.
When the thickness of the layer (region) exhibiting the diffractive ability exceeds 50%, the effects of the present invention such as selective reflection characteristics and circular polarization characteristics due to the cholesteric liquid crystal phase are reduced, and the effect of the present invention may not be obtained. .

As the cholesteric liquid crystal film, a cholesteric alignment film having cholesteric alignment fixed using a polymer liquid crystal or a low molecular weight liquid crystal or a mixture thereof is prepared in advance, and a diffraction element substrate is bonded to the cholesteric alignment film, and heat and / or Or a method of transferring the diffraction pattern of the diffraction element substrate to the alignment film by applying pressure, or after cholesteric alignment of a polymer liquid crystal or a low molecular weight liquid crystal or a mixture thereof using the diffraction element substrate as an alignment substrate, and then changing the alignment state. A cholesteric liquid crystal film having a region exhibiting diffractive ability in a part of the film can be obtained by a method such as a method of immobilizing the film while maintaining it.

The material of the diffraction element substrate used for the transfer of the diffraction pattern may be a material such as a metal or a resin, a material having a diffraction function on the film surface, or a thin film having a diffraction function on the film. Any material may be used as long as it has a diffractive function, such as a material obtained by transferring the same. Above all, in view of ease of handling and mass productivity, a film or a film laminate having a diffraction function is more desirable.

The term "diffraction element" as used herein includes, as its definition, all diffraction elements that generate diffracted light, such as an original flat hologram. The type may be a diffraction element derived from the surface shape, a so-called film thickness modulation hologram type, or a phase element independent of the surface shape or a surface shape converted into a refractive index distribution, a so-called refraction. A rate modulation hologram type may be used. In the present invention, the type of the film thickness modulation hologram is more preferably used because the diffraction pattern information of the diffraction element can be more easily given to the liquid crystal. In addition, any type of refractive index modulation can be suitably used in the present invention as long as it has undulations that cause diffraction in the surface shape.

As a method for transferring a diffraction pattern, for example, generally used heat rollers, laminators,
Using a hot stamp, an electric heating plate, a thermal head, or the like, it can be performed under pressure and heating conditions. The conditions of pressurization and heating differ depending on the physical properties of the polymer liquid crystal and low-molecular liquid crystal to be used, the type of the diffraction element substrate, and the like, and cannot be unconditionally determined, but are usually 0.01 to 100 MPa, preferably 0.1 to 100 MPa. It is appropriately selected depending on the type of liquid crystal, substrate and the like used in the range of 0.05 to 80 MPa and the temperature of 30 to 400 ° C, preferably 40 to 300 ° C.

The polymer liquid crystal used as the film material of the cholesteric liquid crystal film is not particularly limited as long as the cholesteric orientation can be fixed, and any of a main chain type and a side chain type polymer liquid crystal can be used. it can. Specific examples include main-chain liquid crystal polymers such as polyester, polyamide, polycarbonate, and polyesterimide, and side-chain liquid crystal polymers such as polyacrylate, polymethacrylate, polymalonate, and polysiloxane. Among them, a liquid crystalline polyester which has good orientation in forming cholesteric orientation and is relatively easy to synthesize is desirable. As the structural unit of the polymer,
For example, aromatic or aliphatic diol units, aromatic or aliphatic dicarboxylic acid units, and aromatic or aliphatic hydroxycarboxylic acid units are preferred examples.

The low-molecular liquid crystal used as the film material of the cholesteric liquid crystal film has, for example, a biphenyl derivative, a phenylbenzoate derivative, a stilbene derivative or the like, into which a functional group such as an acryloyl group, a vinyl group or an epoxy group is introduced. Things. As the low-molecular liquid crystal, both lyotropic properties and thermotropic properties can be used, but those exhibiting thermotropic properties are more preferable from the viewpoint of workability, process and the like.

In order to form a cholesteric alignment film in which a cholesteric alignment having no region exhibiting a diffractive ability is fixed, a known method, for example, when a high molecular liquid crystal is used, a high molecular liquid crystal is arranged on an alignment substrate. After that, a method may be used in which a cholesteric liquid crystal phase is developed by heat treatment or the like, and the state is rapidly cooled to fix the cholesteric alignment. When using a low-molecular liquid crystal,
After disposing a low-molecular liquid crystal on an alignment substrate, a method of expressing a cholesteric liquid crystal phase by heat treatment or the like and fixing the cholesteric alignment by cross-linking with light, heat or electron beam while maintaining that state is appropriately adopted. can do. In addition, as described above, by using a diffraction element substrate or the like as an alignment substrate, a cholesteric liquid crystal film in which a region exhibiting diffractive ability is formed in an alignment stage can be obtained.

In order to improve the heat resistance and the like of the finally obtained cholesteric liquid crystal film, a bisazide compound or glycidyl compound may be used as long as the cholesteric phase is not impaired in the polymer liquid crystal or low molecular liquid crystal used as the film material. A crosslinking agent such as methacrylate can be added, and by adding these crosslinking agents, crosslinking can be performed in a state where a cholesteric phase is developed. In addition, dichroic dyes, dyes,
Various additives such as pigments may be appropriately added as long as the effects of the present invention are not impaired.

The structure of the cholesteric liquid crystal layer, which is a component of the present invention, usually comprises one layer of a cholesteric liquid crystal film. Further, a cholesteric liquid crystal film may be laminated in a plurality of layers in accordance with the intended use or required optical characteristics, etc., or a cholesteric liquid crystal film having one or more layers may be used. A configuration in which a layer or a plurality of layers are stacked may be used. Further, when two or more cholesteric liquid crystal films and a cholesteric alignment film having no diffractive area are laminated, two or more cholesteric liquid crystal films and cholesteric alignment films may be alternately laminated.

The thickness of the cholesteric liquid crystal layer is usually 0.1.
It is 3 to 20 μm, preferably 0.5 to 10 μm, and more preferably 0.7 to 3 μm. If the ratio is out of this range, the effects of the present invention may not be effectively exhibited. When the film is composed of a plurality of layers, it is desirable that the total thickness of all the films falls within the above range.

The protective layer which is a component of the present invention includes:
There is no particular limitation as long as it has ultraviolet absorption and hard coat properties. For example, a material in which a protective layer-forming material containing an ultraviolet absorber and a hard coat agent is formed into a film, a sheet, a thin film, or a plate. Further, a protective layer having an ultraviolet absorbing property made of a protective layer forming material containing an ultraviolet absorbent (hereinafter, referred to as an ultraviolet absorbing layer) and a protective layer having a hard coating property made of a protective layer forming material containing a hard coat agent (Hereinafter, a hard coat layer) may be used as the protective layer in the present invention. In addition, a laminate of a commercially available ultraviolet cut film and a hard coat film can be used as the protective layer. A laminate formed by applying various hard coat agents to the ultraviolet absorbing layer to form a film can also be used as the protective layer. Here, the ultraviolet absorbing layer and the hard coat layer may each be formed from two or more layers,
Each layer can be laminated via an adhesive layer or the like.

As the material for forming the protective layer, those having high light transmittance are desirable. For example, polyethylene, polypropylene, poly (4-methyl-pentene-1), polystyrene, ionomer, polyvinyl chloride, polymethyl methacrylate, polyethylene terephthalate, polyamide,
A material obtained by adding an ultraviolet absorber and / or a hard coat agent to polysulfone, a cellulose resin, or the like can be used. Further, as the protective layer, an adhesive composition obtained by adding an ultraviolet absorber and / or a hard coat agent to the heat, light or electron beam-curable reactive adhesive described above can also be used. The cured product can be used as a protective layer.

The ultraviolet absorber is not particularly limited as long as it is compatible or dispersible in the material for forming the protective layer. For example, a benzophenone compound, a salicylate compound,
Organic ultraviolet absorbers such as benzotriazole-based compounds, oxalic anilide-based compounds, and cyanoacrylate-based compounds, and inorganic ultraviolet absorbers such as cesium oxide, titanium oxide, and zinc oxide can be used. Among them, a benzophenone-based compound having high ultraviolet absorption efficiency is preferably used. In addition, one or more ultraviolet absorbers can be added. The blending ratio of the ultraviolet absorber in the protective layer varies depending on the material for forming the protective layer to be used.
It is 1 to 20% by weight, preferably 0.5 to 10% by weight.

The hard coat agent is not particularly limited as long as it is compatible or dispersible in the protective layer forming material.
For example, use of an inorganic compound such as an organopolysiloxane-based, photo-curable resin-based acrylic oligomer-based, urethane acrylate-based, epoxy acrylate-based, polyester acrylate-based, thermosetting resin-based acryl-silicone-based, or ceramics. Can be. Above all, an organopolysiloxane-based or photo-curable resin-based acrylic oligomer-based hard coat agent is preferably used from the viewpoint of film-forming properties and the like. These hard coat agents are
Either a solventless type or a solvent type can be used.

The material for forming the protective layer includes, in addition to an ultraviolet absorber and a hard coat agent, if necessary, a light stabilizer such as a hindered amine or a quencher, an antistatic agent, a slipperiness improver, a dye, a pigment, a surfactant. Various additives such as fillers such as fine silica and zirconia can also be blended. The mixing ratio of these various additives is not particularly limited as long as the effects of the present invention are not impaired, but is usually 0.01 to 10% by weight, preferably 0.05 to 5% by weight.

The ultraviolet absorbing layer constituting the protective layer can be formed by using the above-described protective layer forming material, which is appropriately blended with an ultraviolet absorbing agent and, if necessary, a light stabilizer. Further, a commercially available ultraviolet cut film or the like can be used as the ultraviolet absorbing layer in the present invention.

The hard coat layer constituting the protective layer is
The protective layer can be formed by using a material in which a hard coat agent and various additives are added to the protective layer forming material described above. The hard coat layer may be formed by applying the above hard coat agent on a transparent support film. As a transparent support film, polymethyl methacrylate, polystyrene, polycarbonate,
Examples include films formed from polyether sulfone, polyphenylene sulfide, amorphous polyolefin, triacetyl cellulose, polyethylene terephthalate, polyethylene naphthalate, and the like.

The ultraviolet absorbing layer and the hard coat layer are laminated via an adhesive or the like, and can be used as the protective layer in the present invention. Suitable examples of the adhesive include the above-described heat, light, or electron beam curing type reactive adhesive. The protective layer can also be formed by using an adhesive containing an ultraviolet absorbent and laminating a separately prepared hard coat layer on the cholesteric liquid crystal layer. Further, a dye, a pigment, a surfactant and the like may be appropriately added to the adhesive as needed.

Further, as the hard coat layer, a vehicle resin for gravure ink or the like can be preferably used.
Examples of the gravure ink vehicle resin include nitrocellulose, ethylcellulose, polyamide resin, vinyl chloride, chlorinated polyolefin, acrylic resin, polyurethane, and polyester. In addition, hard resins such as ester gum, dammar gum, maleic resin, alkyd resin, phenol resin, ketone resin, xylene resin, terpene resin, petroleum resin, etc. are used in the gravure ink vehicle resin in order to improve adhesion and film strength. May be blended.

The structure of the hard coat layer may be a single hard coat layer or a composite layer according to the required weather resistance and the like. As the composite layer, for example, a hard coat layer containing an organopolysiloxane, a hard coat layer containing a photocurable resin, a hard coat layer containing a thermosetting resin,
A composite layer composed of two or more layers, such as a hard coat layer containing an inorganic compound, may be used as the hard coat layer.

Further, the degree of the hard coat property, that is, the hardness, cannot be determined unconditionally depending on the material constituting the optical laminate of the present invention. However, when the evaluation is performed according to the test method described in JIS L0849, the determination of discoloration is made. It is desirable that the standard is at least 3 or more, preferably 4 or more.

The protective layer, which is a component of the present invention, and the ultraviolet absorbing layer and the hard coat layer constituting the protective layer are generally formed by a roll coating method, a dipping method, a gravure coating method, a bar code method, a spin coating method, or the like. Known methods such as a method, a spray coating method, and a printing method can be employed. After forming a film on the cholesteric liquid crystal layer or the support film by these methods, the protective layer can be formed by performing post-processing according to the protective layer forming material used. Examples of a method for forming a protective layer composed of a composite layer of an ultraviolet absorbing layer and a hard coat layer include, for example, a method in which a hard coating agent is applied directly to the ultraviolet absorbing layer, a method in which the ultraviolet absorbing layer is laminated via an adhesive, and the like. .

The thickness of the protective layer cannot be specified unconditionally because it differs depending on the performance required for the ultraviolet absorbing property and the hard coat property, but it is usually 0.1 to 100 μm, preferably 1 to 50 μm. Also, when the protective layer is formed of a composite layer with an ultraviolet absorbing layer and a hard coat layer, the total thickness of each layer is preferably within the above range.

The method for producing the optical laminate of the present invention includes:
(1) Laminate sequentially on a support substrate to have the configuration of the present invention. (2) Press, heat, and cure the remaining laminate separately manufactured on a support substrate having an adhesive layer formed on the surface in advance. (3)
On the supporting substrate, the remaining laminated body separately prepared is prepared on a peelable substrate, and the peeling substrate is removed by transferring the pressure, heating, curing, etc. to the supporting substrate side alone or in combination. Method and the like.

As a more specific example of the production method, (1) a cholesteric liquid crystal film layer formed on an alignment substrate is
An adhesive layer is formed on a support substrate or a cholesteric liquid crystal film on which an adhesive layer has been formed in advance, and transferred to the support substrate, and the alignment substrate is peeled off. Then, a method of forming a protective layer on the cholesteric liquid crystal film layer,
(2) The cholesteric liquid crystal film formed on the alignment substrate is transferred onto a second substrate different from the alignment substrate via an adhesive layer containing an ultraviolet absorber, and the alignment substrate is peeled off. Next, an adhesive layer is formed on a support substrate or a cholesteric liquid crystal film on which an adhesive layer has been formed in advance, the cholesteric liquid crystal film is transferred to the support substrate, and only the second substrate is peeled off from the cholesteric liquid crystal film. Then, a method of forming a hard coat layer on the surface of the adhesive layer containing an ultraviolet absorber from which the second substrate has been peeled off, (3) applying the cholesteric liquid crystal film formed on the alignment substrate to a second substrate different from the alignment substrate Transfer is performed via the adhesive layer, and the alignment substrate is peeled off. Then the third
The cholesteric liquid crystal film is transferred onto the substrate through an adhesive layer containing an ultraviolet absorber, and the second substrate is peeled off. Next, the cholesteric liquid crystal film is transferred to a support substrate on which an adhesive layer has been formed in advance, and
The substrate is peeled off. A method in which a hard coat layer is formed on the surface of the adhesive layer containing an ultraviolet absorbent from which the third substrate has been peeled off.

Here, the second and third substrates (hereinafter, referred to as the second and third substrates)
It is called a removable substrate. ) Is not particularly limited as long as it is a substrate having removability and self-supporting property, and a plastic film having releasability is usually desirably used as the substrate. The term "removability" as used herein means that in the state where the cholesteric liquid crystal film layer and the removable substrate are bonded via an adhesive, the releasability can be removed at the interface between the adhesive and the removable substrate. As the material of such a removable substrate, specifically, polyethylene, polypropylene, olefin-based resins such as 4-methylpentene-1 resin, polyamide, polyimide, polyamideimide,
Polyetherimide, polyetherimide, polyether ketone, polyether ether ketone, polyether sulfone, polyketone sulfide, polysulfone, polystyrene, polyphenylene sulfide, polyphenylene oxide, polyethylene terephthalate,
Polybutylene terephthalate, polyarylate, polyacetal, polycarbonate, polyvinyl alcohol,
Cellulose plastics and the like can be mentioned. The plastic film formed from these materials may use the plastic film itself as a removable substrate, or a plastic film surface coated with silicone or a fluorine-based resin in order to have an appropriate removable property, or an organic film. Those formed with a thin film or an inorganic thin film, those subjected to a chemical treatment, and those subjected to a physical treatment such as vapor deposition or surface polishing can also be used.

The adhesive used when transferring the cholesteric liquid crystal film layer to the removable substrate is as follows.
Although not particularly limited, it is preferable to use the heat, light or electron beam curing type reactive adhesive described above as appropriate.

Further, examples of the peeling and removing method in the above-mentioned manufacturing method include, for example, a method of applying an adhesive tape to a corner end of an oriented substrate or a removable substrate and artificially peeling it, or mechanically peeling using a roll or the like. Method, method of mechanical peeling after immersion in poor solvent for all structural materials, method of peeling by applying ultrasonic wave in poor solvent, thermal expansion coefficient of alignment substrate, re-peelable substrate and cholesteric liquid crystalline film The method of peeling off by giving a change in temperature by utilizing the difference between them can be appropriately adopted.

The above manufacturing method is merely an example, and the optical laminate of the present invention is not limited to these.

The thus obtained optical laminate of the present invention has a unique effect that the diffracted light has a circular polarization property, which is not possible with conventional optical members. Due to this effect, it is possible to extremely increase the light use efficiency by using, for example, a spectroscopic optical device that requires polarized light, such as an ellipsometer. Conventional spectroscopic optical devices that require polarized light use a diffraction element such as a diffraction grating or prism to separate the light emitted from the light source for each wavelength and then transmit the light through the polarizer, or transmit the light through the polarizer and then separate the light. It was necessary to have a polarizer. This polarizer has a problem that it absorbs about 50% of the incident light and has a problem of extremely low light utilization efficiency due to reflection at the interface. As a result, the light use efficiency is extremely high, and it is theoretically possible to use about 100%. Further, the optical laminate of the present invention can easily control transmission and blocking of diffracted light by using a normal polarizing plate. Normally, diffracted light having no polarization cannot be completely blocked by any combination of polarizing plates. That is, in the optical laminate of the present invention, for example, diffracted light having
Only when the left circularly polarizing plate is used, the light can be completely blocked, and even when other polarizing plates are used, the complete blocking cannot be realized. Because of such an effect, for example, in an environment in which an observer observes a diffraction image through a polarizing plate, by changing the state of the polarizing plate, the diffraction image suddenly emerges from the dark field, or suddenly disappears. It becomes possible.

As described above, the optical laminate of the present invention has a very wide range of applications as a new diffraction function element, and can be used as various optical elements, optoelectronic elements, decorative members, and forgery prevention elements. Can be.

Specifically, as an optical element or an optoelectronic element, for example, a transparent and isotropic film as a support substrate, for example, Fujitac (Fuji Photo Film Co., Ltd.)
Triacetylcellulose film such as Konica Catac (Konica Corporation), TPX film (Mitsui Chemicals Co., Ltd.), Arton film (Nippon Synthetic Rubber Co., Ltd.)
ZEONEX Film (Zeon Corporation),
By using the acrylene film (manufactured by Mitsubishi Rayon Co., Ltd.) or the like to obtain the optical laminate of the present invention, it is possible to develop the optical laminate for various optical applications. For example, the optical laminated body is formed by TN (twisted nematic) -L
CD (Liquid Crystal Display)
y), STN (Super Twisted Nema)
tic) -LCD, ECB (Electrically)
Controlled Birefringenc
e) -LCD, OMI (Optical Mode I)
interference) -LCD, OCB (Opti)
cally Compensated Birefrin
gence) -LCD, HAN (Hybrid Ali)
gned Nematic) -LCD, IPS (In
Various LCDs with improved color compensation and / or improved viewing angle can be obtained by providing a liquid crystal display such as a plane switching (LCD). Further, the optical laminate can be used as a spectroscopic optical device that requires polarized light separated as described above, a polarizing optical element that obtains a specific wavelength by a diffraction phenomenon, an optical filter, a circularly polarizing plate, a light diffusing plate, and the like. In addition, it is possible to provide various optical members that can exhibit an optical effect that has not existed conventionally as an optical element or an optoelectronic element, such as obtaining a linear polarizing plate by combining with a quarter-wave plate. .

Various decorative molding materials can be obtained as decorative members, including a new decorative film having both a rainbow color effect by diffractive power and a vivid color effect by cholesteric liquid crystal. In addition, since it can be made into a thin film, it can be expected to greatly contribute to differentiation from other similar products by a method of attaching it to an existing product or the like or integrating it. For example, when the optical laminate of the present invention incorporating a diffractive pattern having a design is attached to a glass window or the like, the selective reflection characteristic of the cholesteric liquid crystal accompanied by the diffraction pattern looks different from the outside depending on the viewing angle. , It will be excellent in fashionability. In addition, it is possible to provide a window in which the inside is hardly seen from the bright outside, and the outside is excellent in the interior from the inside.

The anti-counterfeit element can be used as a new anti-counterfeit film, seal, label or the like having both the anti-counterfeit effect of the diffraction element and the cholesteric liquid crystal. Specifically, as a supporting substrate constituting the optical laminate of the present invention, for example, a card substrate such as a car driver's license, an identification card, a passport, a credit card, a prepaid card, various cash vouchers, a gift card, a securities, a mount, etc. By using the optical laminate, the optical laminate of the present invention can be integrated with a card substrate, a mount, or the like or provided partially, specifically, attached, embedded, or woven into paper. Further, the optical laminate of the present invention has a region exhibiting diffractive power in a part of the cholesteric liquid crystal layer and is covered with a protective layer, and also has a wavelength-selective reflectivity, a circularly-polarized light selective reflectivity, and a color viewing angle of the cholesteric liquid crystal. Dependency and the effect of exhibiting a beautiful cholesteric color. Therefore, when the optical laminate of the present invention is used as an anti-counterfeiting element, forgery of the laminate is difficult, and more specifically, the diffractive power constituting the optical laminate of the present invention is partially used. It can be said that forgery of the cholesteric liquid crystal layer is extremely difficult. In addition to the anti-counterfeit effect,
Since it has the iridescent color effect of the diffraction element and the vivid color effect of the cholesteric liquid crystal, it is also excellent in design. From these facts, the optical laminate of the present invention is very useful as an element for preventing forgery.

These applications are only examples, and the optical laminate of the present invention can be used in various applications where a single diffractive element or a single cholesteric liquid crystal film is conventionally used, or can exhibit a new optical effect. Because it is possible, it can be applied to various applications other than the above-mentioned applications.

[0055]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

Reference Example 1 Synthesis of Liquid Crystalline Polyester
Terephthalic acid 50 mmol, hydroxybenzoic acid 20 m
mol, 20 mmol of catechol, 10 mmol of (R) -2-methyl-1,4-butanediol and 100 mg of sodium acetate at 180 ° C. under a nitrogen atmosphere.
The polycondensation reaction was performed while the temperature was raised stepwise at 200 ° C. for 1 hour and at 250 ° C. for 1 hour. Next, the polycondensation reaction was continued at 250 ° C. for 2 hours while flowing nitrogen, and the polycondensation was further performed at the same temperature under reduced pressure for 1 hour. After dissolving the obtained polymer in tetrachloroethane, reprecipitation was performed with methanol to obtain a liquid crystalline polyester.

An N-methyl-2-pyrrolidone solution (20% by weight) of the obtained liquid crystalline polyester was prepared, and the solution was applied on a rubbed polyphenylene sulfide film by a spin coating method. After the application, a drying treatment was performed to remove N-methyl-2-pyrrolidone, and a liquid crystalline polyester coating film was formed on the polyphenylene sulfide film.

Next, the coating film of the liquid crystalline film was
A heat treatment was performed in a heating atmosphere at a temperature of 5 ° C. for 5 minutes, and the resultant was cooled to room temperature to obtain a liquid crystalline polyester film exhibiting a golden specular reflection on a polyphenylene sulfide film.

When the transmission spectrum of the film was measured with an ultraviolet-visible-near-infrared spectrophotometer V-570 manufactured by JASCO Corporation, the selective reflection having a center wavelength of about 600 nm and a selective reflection wavelength bandwidth of about 100 nm was observed. It was confirmed that the film was a cholesteric alignment film in which the cholesteric alignment shown was fixed. When the orientation state of the cholesteric alignment film was observed with a polarizing microscope and a transmission electron microscope of the cross section of the film, the helical axis orientation in the cholesteric phase was uniformly parallel to the film thickness direction, and the helical pitch was uniform in the film thickness direction. It was confirmed that the cholesteric orientation was formed at regular intervals.

The analysis methods of the obtained polyester are as follows. (1) Logarithmic viscosity of polymer Using a Ubbelohde viscometer, phenol / tetrachloroethane = 60/40 (weight ratio), a concentration of 0.5 g /
The measurement was performed at 100 ° C. and 30 ° C. (2) Glass transition point (Tg) Measured using a Du Pont 990 Thermal Analyzer. (3) Identification of Liquid Crystal Phase Observed using a BH2 polarizing microscope manufactured by Olympus Optical Co., Ltd.

Reference Examples 2 to 10 Liquid crystalline polyesters of various compositions were synthesized in the same manner as in Reference Example 1. Table 1 shows the results. Further, N-methyl-2-pyrrolidone solutions were prepared from various liquid crystalline polyesters in the same manner as in Reference Example 1,
By performing heat treatment, a cholesteric alignment film was obtained on the polyphenylene sulfide film used as the alignment substrate. Table 1 shows the selective reflection colors of the obtained film.

When the orientation state of each of the obtained films was observed by a polarizing microscope and a transmission electron microscope of a cross section of the film, the helical axis orientation in the cholesteric phase was uniformly parallel to the film thickness direction, and the helical pitch was It was confirmed that cholesteric orientations were formed at regular intervals in the film thickness direction.

[0063]

[Table 1]

In Table 1, each symbol means the following compound. TPA: Terephthalic acid, MHQ: Methylhydroquinone, CT: Catechol, MBD: (R) -2-methyl-1,4-butanediol, BP
DA: 4,4'-biphenyldicarboxylic acid, CHQ: chlorohydroquinone, MHD: (R) -3-methyl-1,6-hexanediol, HB
A: hydroxybenzoic acid, NDCA: 2,6-naphthalenedicarboxylic acid, HQ: hydroquinone, CCT: 3-chlorocatechol, DMBD: (R) (R) -2,3-dimethyl-1,4-butanediol, t -BHQ: t-butylhydroquinone, PA: phthalic acid

(Example 1) An adhesive made of a commercially available photocurable acrylic oligomer was applied to the cholesteric alignment surface of the cholesteric alignment film obtained in Reference Example 1 using a bar coater to a thickness of 5 µm. did. Next, a triacetyl cellulose (TAC) film was adhered to the adhesive applied surface of the film using a desktop laminator, and irradiated with ultraviolet rays to cure the adhesive.

After the adhesive was cured, the end of the polyphenylene sulfide film used as the alignment substrate was held by hand, and the polyphenylene sulfide film was peeled off at 180 ° in the interface between the film and the cholesteric alignment film. Oriented film / adhesive layer /
The laminated body laminated | stacked in order of the TAC film was obtained.

Next, a ruled line diffraction grating film manufactured by Edmund Scientific Japan (900 / m)
m) The cholesteric alignment film surface of the laminate is overlapped so that the diffraction surface of m) faces each other, and heated and pressed at 120 ° C., 0.3 MPa, and a roll contact time of 1 second using a laminator DX-350 manufactured by Tokyo Laminex. (Diffraction grating film / cholesteric alignment film / adhesive layer / T
AC film). After cooling to room temperature, the diffraction grating film was removed. Observation of the cholesteric alignment film surface on which the diffraction grating film was superimposed revealed that iridescent color caused by the diffraction pattern and selective reflection peculiar to the cholesteric liquid crystal were clearly recognized. Also, when the orientation state of the cholesteric alignment film surface from which the diffraction grating film was removed was observed by a polarizing microscope and a transmission electron microscope of the liquid crystal layer cross section, the helical axis orientation in the cholesteric phase was not uniformly parallel to the film thickness direction. It was also confirmed that cholesteric alignment in which the helical pitch was not uniformly spaced in the film thickness direction was formed in the surface region of the liquid crystal layer. In other regions, it was confirmed that a cholesteric orientation in which the helical axis orientation was uniformly parallel to the film thickness direction and the helical pitch was uniformly uniform in the film thickness direction was formed.
In addition, He-N
When an e-laser (wavelength 632.8 nm) is incident,
Laser light was observed at emission angles of 0 ° and about ± 35 °. In order to further confirm the polarization characteristics, the obtained laminate was placed under normal room illumination and observed through a right circularly polarizing plate (transmitting only right circularly polarized light). And the brightness when observed without a polarizing plate was almost the same. On the other hand, a left circularly polarizing plate (only left circularly polarized light is transmitted)
Observed through the above, a dark field was obtained, and no iridescent reflected and diffracted light was observed.

From these results, it was confirmed that in the cholesteric alignment film constituting the laminate, a region exhibiting diffractive ability was formed in the film surface region, and that the diffracted light was right-handed circularly polarized light. From this, it was also found that the cholesteric alignment film constituting the laminate becomes a cholesteric liquid crystal layer which is a component of the present invention.

The cholesteric liquid crystal layer of the laminate (cholesteric liquid crystal layer / adhesive layer / TAC film) was coated with a benzophenone-based ultraviolet absorber Cyasorb UV-24.
UV curable adhesive containing 5.0% by weight (manufactured by Scitech) (Aronix UV-363 manufactured by Toagosei Co., Ltd.)
0 (trade name) is diluted with the company's M-150 (trade name) and the company's M-315 (trade name), and the viscosity is 300 mPa.
.S) was applied with a bar coater so as to have a thickness of 5 μm, and was irradiated with ultraviolet rays to be cured to obtain an optical laminate of the present invention.

The accelerated light resistance test of the obtained optical laminate was performed using a xenon arc lamp type light resistance tester Santester CPS manufactured by Shimadzu Corporation with a sample surface irradiance of 100 W / m ² (wavelength range 300 to 700 nm) and a test time of 100. It was performed under the condition of time.

As a result of the test, when the reflection color of the optical laminate and the reflection color before the test were visually compared and observed, no difference was observed in the reflection color. Even after the accelerated light resistance test, the rainbow caused by the diffraction pattern was observed. Color coloring characteristics and selective reflection characteristics specific to cholesteric liquid crystals were maintained. Further, when the alignment state and the diffractive polarization effect of the cholesteric liquid crystal layer constituting the optical laminate were observed, no change was observed from the state before the test.

Next, a friction resistance test of the obtained optical laminate was performed using a friction tester FR-I type manufactured by Suga Test Instruments Co., Ltd. The laminate was fixed such that the protective layer was on the upper surface, a dry white cotton cloth was attached to the friction element, and a friction operation of 50 reciprocations was performed between 10 cm on the test piece for 50 seconds for 50 seconds. When the protective layer after the test was visually observed, almost no damage was found on the protective layer, and the discoloration criterion was 3.

Example 2 A commercially available adhesive composed of a photo-curable acrylic oligomer was applied to the cholesteric alignment surface of the cholesteric alignment film obtained in Reference Example 2 using a bar coater so as to have a thickness of 5 μm. did. Next, a triacetyl cellulose (TAC) film was adhered to the adhesive applied surface of the film using a desktop laminator, and irradiated with ultraviolet rays to cure the adhesive.

After the adhesive was cured, the end of the polyphenylene sulfide film used as the alignment substrate was gripped by hand, and the polyphenylene sulfide film was peeled off at 180 ° in the interface between the film and the cholesteric alignment film. Oriented film / adhesive layer /
The laminated body laminated | stacked in order of the TAC film was obtained.

Next, a ruled-line diffraction grating film manufactured by Edmund Scientific Japan (900 / m
m) The cholesteric alignment film surface of the laminate is overlapped so that the diffraction surface of m) faces each other, and heated and pressed at 120 ° C., 0.3 MPa, and a roll contact time of 1 second using a laminator DX-350 manufactured by Tokyo Laminex. (Diffraction grating film / cholesteric alignment film / adhesive layer / T
AC film). After cooling to room temperature, the diffraction grating film was removed. Observation of the cholesteric alignment film surface on which the diffraction grating film was superimposed revealed that iridescent color caused by the diffraction pattern and selective reflection peculiar to the cholesteric liquid crystal were clearly recognized. Also, when the orientation state of the cholesteric alignment film surface from which the diffraction grating film was removed was observed by a polarizing microscope and a transmission electron microscope of the liquid crystal layer cross section, the helical axis orientation in the cholesteric phase was not uniformly parallel to the film thickness direction. It was also confirmed that cholesteric alignment in which the helical pitch was not uniformly spaced in the film thickness direction was formed in the surface region of the liquid crystal layer. In other regions, it was confirmed that a cholesteric orientation in which the helical axis orientation was uniformly parallel to the film thickness direction and the helical pitch was uniformly uniform in the film thickness direction was formed.
In addition, He-N
When an e-laser (wavelength 632.8 nm) is incident,
Laser light was observed at emission angles of 0 ° and about ± 35 °. In order to further confirm the polarization characteristics, the obtained laminate was placed under normal room illumination and observed through a right circularly polarizing plate (transmitting only right circularly polarized light). And the brightness when observed without a polarizing plate was almost the same. On the other hand, a left circularly polarizing plate (only left circularly polarized light is transmitted)
Observed through the above, a dark field was obtained, and no iridescent reflected and diffracted light was observed.

From these results, it was confirmed that in the cholesteric alignment film constituting the laminate, a region exhibiting diffractive ability was formed in the film surface region, and that the diffracted light was right-handed circularly polarized light. From this, it was also found that the cholesteric alignment film constituting the laminate becomes a cholesteric liquid crystal layer which is a component of the present invention.

An ultraviolet-curing adhesive obtained by adding 5.0% by weight of a triazole-based ultraviolet absorber SEESORB702 (manufactured by Cipro Kasei Co., Ltd.) to the cholesteric liquid crystal layer surface of the laminate (cholesteric liquid crystal layer / adhesive layer / TAC film). (Aronix UV-3630 manufactured by Toagosei Co., Ltd.
(Trade name) was diluted with the company's M-150 (trade name) and the company's M-315 (trade name), and the viscosity was 300 mPa ·
s) was applied using a bar coater to a thickness of 5 μm, and was irradiated with ultraviolet rays and cured to obtain an optical laminate of the present invention.

Even when a protective layer provided with ultraviolet absorbing property and hard coat property is laminated, the obtained optical laminated body can be converted into iridescent and cholesteric liquid crystals caused by a diffraction pattern in the same manner as before laminating the absorbing layer. The characteristic selective reflection was clearly recognized.

(Example 3) A cholesteric alignment surface of the cholesteric alignment film obtained in Reference Example 3 was combined with a diffraction surface of a ruled diffraction grating film (900 lines / mm) manufactured by Edmund Scientific Japan and a laminate. Of the cholesteric alignment film faces each other, and using a laminator DX-350 manufactured by Tokyo Laminex Co., Ltd., 1
Heating and pressing were performed under the conditions of 20 ° C., 0.3 MPa, and a roll contact time of 1 second (diffraction grating film / cholesteric alignment film / polyphenylene sulfide film). After cooling to room temperature, the diffraction grating film was removed.

Next, an adhesive made of a commercially available photo-curable acrylic oligomer was applied to the cholesteric alignment film surface from which the diffraction grating film had been removed using a bar coater so as to have a thickness of 5 μm. Next, a triacetyl cellulose (TAC) film was adhered to the adhesive applied surface of the film using a desktop laminator, and irradiated with ultraviolet rays to cure the adhesive.

After the adhesive is cured, the end of the polyphenylene sulfide film used as the alignment substrate is held by hand, and the polyphenylene sulfide film is peeled off at 180 ° in the interface between the film and the cholesteric alignment film. Oriented film / adhesive layer /
The laminated body laminated | stacked in order of the TAC film was obtained.

When the surface of the cholesteric alignment film constituting the obtained laminate was observed, rainbow colors caused by the diffraction pattern and selective reflection peculiar to the cholesteric liquid crystal were clearly recognized. Also, when the orientation state of the cholesteric alignment film surface from which the diffraction grating film was removed was observed by a polarizing microscope and a transmission electron microscope of the liquid crystal layer cross section, the helical axis orientation in the cholesteric phase was not uniformly parallel to the film thickness direction. It was also confirmed that cholesteric alignment in which the helical pitch was not uniformly spaced in the film thickness direction was formed in the surface region of the liquid crystal layer. In other regions, it was confirmed that a cholesteric orientation in which the helical axis orientation was uniformly parallel to the film thickness direction and the helical pitch was uniformly uniform in the film thickness direction was formed. When a He-Ne laser (wavelength 632.8 nm) was perpendicularly incident on the cholesteric alignment film surface, laser light was observed at an emission angle of 0 ° and about ± 35 °. In order to further check the polarization characteristics, place the laminate obtained under normal indoor lighting and place a right circularly polarizing plate (transmitting only right circularly polarized light)
As a result, rainbow-colored reflected diffraction light was observed, which was almost the same as the brightness when observed without a polarizing plate. On the other hand, observation through a left circularly polarizing plate (transmitting only left circularly polarized light) revealed a dark field, and no iridescent reflected and diffracted light was observed.

From these results, it was confirmed that in the cholesteric alignment film constituting the laminate, a region exhibiting diffractive ability was formed in the film surface region, and that the diffracted light was right-handed circularly polarized light. From this, it was also found that the cholesteric alignment film constituting the laminate becomes a cholesteric liquid crystal layer which is a component of the present invention.

On the cholesteric liquid crystal layer surface of the laminate (cholesteric liquid crystal layer / adhesive layer / TAC film), an ultraviolet absorber Cyasorb UV-24 (manufactured by Scitech) was applied.
(Aronix UV-3630 (trade name) manufactured by Toagosei Co., Ltd. is diluted with M-111 (trade name) manufactured by Toagosei Co., Ltd.), and the viscosity is set to 250 mPa.
.S) was applied with a bar coater so as to have a thickness of 5 μm, and was irradiated with ultraviolet rays and cured to form an ultraviolet absorbing layer. Next, a silicone-based varnish KR9706 (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.) was applied on the ultraviolet absorbing layer to a thickness of 5 μm with a bar coater, and heated and cured to form a silicone-based hard coat layer. Was obtained.

Even if a protective layer consisting of an ultraviolet absorbing layer and a hard coat layer is laminated on the obtained optical laminate, the rainbow-colored cholesteric liquid crystal and the rainbow-colored cholesteric liquid crystal caused by the diffraction pattern remain the same as before the protective layer is laminated. Selective reflection was clearly recognized.

In the same manner as in Example 1, accelerated light resistance and rub resistance tests were performed. Before and after the test, no change was observed in the selective reflection caused by the iridescent cholesteric liquid crystal caused by the diffraction pattern. The criterion for discoloration was 4.

Example 4 An adhesive made of a commercially available photo-curable acrylic oligomer was applied to the cholesteric alignment surface of the cholesteric alignment film obtained in Reference Example 4 using a bar coater so as to have a thickness of 5 μm. did. Next, a polyvinyl chloride sheet is attached to the adhesive applied surface of the film using a desktop laminator, and irradiated with ultraviolet light,
The adhesive was cured.

After the adhesive was cured, the end of the polyphenylene sulfide film used as the alignment substrate was held by hand, and the polyphenylene sulfide film was peeled off at 180 ° in the interface between the film and the cholesteric alignment film. Oriented film / adhesive layer /
A laminate was obtained in which polyvinyl chloride sheets were laminated in this order.

Next, a ruled line diffraction grating film manufactured by Edmund Scientific Japan (900 / m)
m) The cholesteric alignment film surface of the laminate is overlapped so that the diffraction surface of m) faces each other, and heated and pressed at 120 ° C., 0.3 MPa, and a roll contact time of 1 second using a laminator DX-350 manufactured by Tokyo Laminex. (Diffraction grating film / cholesteric alignment film / adhesive layer / polyvinyl chloride sheet). After cooling to room temperature, the diffraction grating film was removed. Observation of the cholesteric alignment film surface on which the diffraction grating film was superimposed revealed that iridescent color caused by the diffraction pattern and selective reflection peculiar to the cholesteric liquid crystal were clearly recognized. Also, when the orientation state of the cholesteric alignment film surface from which the diffraction grating film was removed was observed by a polarizing microscope and a transmission electron microscope of the liquid crystal layer cross section, the helical axis orientation in the cholesteric phase was not uniformly parallel to the film thickness direction. It was also confirmed that cholesteric alignment in which the helical pitch was not uniformly spaced in the film thickness direction was formed in the surface region of the liquid crystal layer.
In other regions, it was confirmed that a cholesteric orientation in which the helical axis orientation was uniformly parallel to the film thickness direction and the helical pitch was uniformly uniform in the film thickness direction was formed. Also, H is vertically set in the plane of the cholesteric alignment film.
When an e-Ne laser (wavelength 632.8 nm) was incident, laser light was observed at an emission angle of 0 ° and about ± 35 °. In order to further confirm the polarization characteristics, the obtained laminate was placed under normal room illumination and observed through a right circularly polarizing plate (transmitting only right circularly polarized light). And the brightness when observed without a polarizing plate was almost the same. On the other hand, observation through a left circularly polarizing plate (transmitting only left circularly polarized light) revealed a dark field, and no iridescent reflected and diffracted light was observed.

From these results, it was confirmed that in the cholesteric alignment film constituting the laminate, a region having a diffractive ability was formed in the film surface region, and that the diffracted light was right-handed circularly polarized light. From this, it was also found that the cholesteric alignment film constituting the laminate becomes a cholesteric liquid crystal layer which is a component of the present invention.

An ultraviolet curable adhesive obtained by adding 5.0% by weight of an ultraviolet absorber Cyasorb UV-24 (manufactured by Scitech) to the cholesteric liquid crystal layer surface of the laminate (cholesteric liquid crystal layer / adhesive layer / polyvinyl chloride sheet) ( Alonix UV-3630 (trade name) manufactured by Toagosei Co., Ltd. was changed to M-150 (trade name) manufactured by Toagosei Co., Ltd. and M-3 manufactured by Toagosei Co., Ltd.
Diluted with 15 (trade name) and adjusted to a viscosity of 300 mPa · s) with a bar coater so as to have a thickness of 5 μm, irradiated with ultraviolet rays, and cured to give ultraviolet absorption and hard coat properties. The protective layer was formed to obtain the optical laminate of the present invention.

The accelerated light resistance test of the obtained optical laminate was performed using a xenon arc lamp type light resistance tester Santester CPS manufactured by Shimadzu Corporation with a sample surface irradiance of 100 W / m ² (wavelength range 300 to 700 nm) and a test time of 100. It was performed under the condition of time.

As a result of the test, when the reflected color of the optical laminate and the reflected color before the test were visually observed, no difference was observed in the reflected color, and even after the accelerated light resistance test, the rainbow caused by the diffraction pattern was observed. Color coloring characteristics and selective reflection characteristics specific to cholesteric liquid crystals were maintained. Further, when the alignment state and the diffractive polarization effect of the cholesteric liquid crystal layer constituting the optical laminate were observed, no change was observed from the state before the test.

Example 5 The cholesteric alignment surface of the cholesteric alignment film obtained in Reference Example 5 was laminated with the diffraction surface of a ruled diffraction grating film (900 lines / mm) manufactured by Edmund Scientific Japan. Of the cholesteric alignment film faces each other, and using a laminator DX-350 manufactured by Tokyo Laminex Co., Ltd., 1
Heating and pressing were performed under the conditions of 20 ° C., 0.3 MPa, and a roll contact time of 1 second (diffraction grating film / cholesteric alignment film / polyphenylene sulfide film). After cooling to room temperature, the diffraction grating film was removed.

Next, an adhesive made of a commercially available photocurable acrylic oligomer was applied to the cholesteric alignment film surface from which the diffraction grating film had been removed using a bar coater so as to have a thickness of 5 μm. Next, synthetic paper was bonded to the adhesive-coated surface of the film using a desktop laminator, and irradiated with ultraviolet light to cure the adhesive.

After the adhesive was cured, the end of the polyphenylene sulfide film used as the alignment substrate was held by hand, and the polyphenylene sulfide film was peeled off at 180 ° in the interface between the film and the cholesteric alignment film. Oriented film / adhesive layer /
A laminate laminated in the order of synthetic paper was obtained.

When the surface of the cholesteric alignment film constituting the obtained laminate was observed, iridescence caused by the diffraction pattern and selective reflection peculiar to the cholesteric liquid crystal were clearly recognized. Also, when the orientation state of the cholesteric alignment film surface from which the diffraction grating film was removed was observed by a polarizing microscope and a transmission electron microscope of the liquid crystal layer cross section, the helical axis orientation in the cholesteric phase was not uniformly parallel to the film thickness direction. It was also confirmed that cholesteric alignment in which the helical pitch was not uniformly spaced in the film thickness direction was formed in the surface region of the liquid crystal layer. In other regions, it was confirmed that a cholesteric orientation in which the helical axis orientation was uniformly parallel to the film thickness direction and the helical pitch was uniformly uniform in the film thickness direction was formed. When a He-Ne laser (wavelength 632.8 nm) was perpendicularly incident on the cholesteric alignment film surface, laser light was observed at an emission angle of 0 ° and about ± 35 °. In order to further check the polarization characteristics, place the laminate obtained under normal indoor lighting and place a right circularly polarizing plate (transmitting only right circularly polarized light)
As a result, rainbow-colored reflected diffraction light was observed, which was almost the same as the brightness when observed without a polarizing plate. On the other hand, observation through a left circularly polarizing plate (transmitting only left circularly polarized light) revealed a dark field, and no iridescent reflected and diffracted light was observed.

From these results, it was confirmed that in the cholesteric alignment film constituting the laminate, a region exhibiting diffractive ability was formed in the film surface region, and that the diffracted light was right-handed circularly polarized light. From this, it was also found that the cholesteric alignment film constituting the laminate becomes a cholesteric liquid crystal layer which is a component of the present invention.

On the cholesteric liquid crystal layer surface of the laminate (cholesteric liquid crystal layer / adhesive layer / synthetic paper), an ultraviolet absorber Cyasorb UV-24 (manufactured by Scitech) was applied 5.0.
UV curable adhesive (Aronix UV-3630 (trade name) manufactured by Toagosei Co., Ltd.
11 (trade name, diluted to a viscosity of 250 mPa · s) was applied by a bar coater so as to have a thickness of 5 μm, and irradiated with ultraviolet rays to be cured to obtain an optical laminate of the present invention.

In the obtained optical laminate, even when the ultraviolet absorbing layer was laminated, the iridescent color caused by the diffraction pattern and the selective reflection characteristic of the cholesteric liquid crystal were clearly recognized as before the lamination of the absorbing layer. Was done.

Example 6 A commercially available adhesive composed of a photocurable acrylic oligomer was applied to the cholesteric alignment surface of the cholesteric alignment film obtained in Reference Example 6 using a bar coater to a thickness of 5 μm. did. Next, a polyvinyl chloride sheet is attached to the adhesive applied surface of the film using a desktop laminator, and irradiated with ultraviolet light,
The adhesive was cured.

After the adhesive was cured, the end of the polyphenylene sulfide film used as the alignment substrate was held by hand, and the polyphenylene sulfide film was peeled and removed at 180 ° in the interface between the film and the cholesteric alignment film. Oriented film / adhesive layer /
A laminate was obtained in which polyvinyl chloride sheets were laminated in this order.

Next, a ruled line diffraction grating film manufactured by Edmund Scientific Japan (900 / m)
m) The cholesteric alignment film surface of the laminate is overlapped so that the diffraction surface of m) faces each other, and heated and pressed at 120 ° C., 0.3 MPa, and a roll contact time of 1 second using a laminator DX-350 manufactured by Tokyo Laminex. (Diffraction grating film / cholesteric alignment film / adhesive layer / polyvinyl chloride sheet). After cooling to room temperature, the diffraction grating film was removed. Observation of the cholesteric alignment film surface on which the diffraction grating film was superimposed revealed that iridescent color caused by the diffraction pattern and selective reflection peculiar to the cholesteric liquid crystal were clearly recognized. Also, when the orientation state of the cholesteric alignment film surface from which the diffraction grating film was removed was observed by a polarizing microscope and a transmission electron microscope of the liquid crystal layer cross section, the helical axis orientation in the cholesteric phase was not uniformly parallel to the film thickness direction. It was also confirmed that cholesteric alignment in which the helical pitch was not uniformly spaced in the film thickness direction was formed in the surface region of the liquid crystal layer.
In other regions, it was confirmed that a cholesteric orientation in which the helical axis orientation was uniformly parallel to the film thickness direction and the helical pitch was uniformly uniform in the film thickness direction was formed. Also, H is vertically set in the plane of the cholesteric alignment film.
When an e-Ne laser (wavelength 632.8 nm) was incident, laser light was observed at an emission angle of 0 ° and about ± 35 °. In order to further confirm the polarization characteristics, the obtained laminate was placed under normal room illumination and observed through a right circularly polarizing plate (transmitting only right circularly polarized light). And the brightness when observed without a polarizing plate was almost the same. On the other hand, observation through a left circularly polarizing plate (transmitting only left circularly polarized light) revealed a dark field, and no iridescent reflected and diffracted light was observed.

From these results, it was confirmed that in the cholesteric alignment film constituting the laminate, a region exhibiting diffractive ability was formed in the film surface region, and that the diffracted light was right-handed circularly polarized light. From this, it was also found that the cholesteric alignment film constituting the laminate becomes a cholesteric liquid crystal layer which is a component of the present invention.

An adhesive (5) made of a photo-curable acrylic oligomer was applied to the cholesteric liquid crystal layer surface of the laminate (cholesteric liquid crystal layer / adhesive layer / polyvinyl chloride sheet).
μm) through a PET-based UV cut film (25 μm).
m) were laminated to obtain an optical laminate of the present invention.

The accelerated light resistance test of the obtained optical laminate was performed using a xenon arc lamp type light resistance tester Santester CPS manufactured by Shimadzu Corporation with a sample surface irradiance of 100 W / m ² (wavelength range of 300 to 700 nm) and a test time of 100. It was performed under the condition of time.

As a result of the test, when the reflected color of the optical laminate and the reflected color before the test were visually observed, no difference was observed in the reflected color, and even after the accelerated light resistance test, the rainbow caused by the diffraction pattern was observed. Color coloring characteristics and selective reflection characteristics specific to cholesteric liquid crystals were maintained. Further, when the alignment state and the diffractive polarization effect of the cholesteric liquid crystal layer constituting the optical laminate were observed, no change was observed from the state before the test.

Next, a friction resistance test of the obtained optical laminate was performed using a friction tester FR-I type manufactured by Suga Test Instruments Co., Ltd. The laminate was fixed such that the protective layer was on the upper surface, a dry white cotton cloth was attached to the friction element, and a friction operation of 50 reciprocations was performed between 10 cm on the test piece for 50 seconds for 50 seconds. When the protective layer after the test was visually observed, almost no damage was found on the protective layer. The criterion for discoloration was 3-4.

Example 7 An adhesive made of a commercially available photocurable acrylic oligomer was applied to the cholesteric alignment surface of the cholesteric alignment film obtained in Reference Example 7 using a bar coater to a thickness of 5 μm. did. Next, a glass substrate is attached to the adhesive applied surface of the film,
The adhesive was cured by irradiation with ultraviolet rays.

After the adhesive was cured, the end of the polyphenylene sulfide film used as the alignment substrate was held by hand, and the polyphenylene sulfide film was peeled off at 180 ° in the interface between the film and the cholesteric alignment film. Oriented film / adhesive layer /
The laminated body laminated | stacked in order of the glass substrate was obtained.

Next, a scored diffraction grating film (900 / m) manufactured by Edmund Scientific Japan
m) The cholesteric alignment film surface of the laminate is overlapped so that the diffraction surface of m) faces each other, and heated and pressed at 120 ° C., 0.3 MPa, and a roll contact time of 1 second using a laminator DX-350 manufactured by Tokyo Laminex. (Diffraction grating film / cholesteric alignment film / adhesive layer / glass substrate). After cooling to room temperature, the diffraction grating film was removed. Observation of the cholesteric alignment film surface on which the diffraction grating film was superimposed revealed that iridescent color caused by the diffraction pattern and selective reflection peculiar to the cholesteric liquid crystal were clearly recognized. Also, when the orientation state of the cholesteric alignment film surface from which the diffraction grating film was removed was observed by a polarizing microscope and a transmission electron microscope of the liquid crystal layer cross section, the helical axis orientation in the cholesteric phase was not uniformly parallel to the film thickness direction. It was also confirmed that cholesteric alignment in which the helical pitch was not uniformly spaced in the film thickness direction was formed in the surface region of the liquid crystal layer. In other regions, it was confirmed that a cholesteric orientation in which the helical axis orientation was uniformly parallel to the film thickness direction and the helical pitch was uniformly uniform in the film thickness direction was formed. When a He-Ne laser (wavelength 632.8 nm) was perpendicularly incident on the cholesteric alignment film surface, laser light was observed at an emission angle of 0 ° and about ± 35 °.
In order to further confirm the polarization characteristics, the obtained laminate was placed under normal room illumination and observed through a right circularly polarizing plate (transmitting only right circularly polarized light). And the brightness when observed without a polarizing plate was almost the same. On the other hand, observation through a left circularly polarizing plate (transmitting only left circularly polarized light) revealed a dark field, and no iridescent reflected and diffracted light was observed.

From these results, it was confirmed that in the cholesteric alignment film constituting the laminate, a region having a diffractive ability was formed in the film surface region, and that the diffracted light was right-handed circularly polarized light. From this, it was also found that the cholesteric alignment film constituting the laminate becomes a cholesteric liquid crystal layer which is a component of the present invention.

An ultraviolet-curing adhesive (Toagosei Co., Ltd.) in which 5.0% by weight of an ultraviolet absorber Cyasorb UV-24 (manufactured by Scitech) was added to the cholesteric liquid crystal layer surface of the laminate (cholesteric liquid crystal layer / adhesive layer / glass substrate). Aronix UV-3630 (trade name) manufactured by Co., Ltd. is diluted with M-111 (trade name) manufactured by the company, and the viscosity is 250 mPa.
.S) was applied with a bar coater so as to have a thickness of 5 μm, and was irradiated with ultraviolet rays and cured to form an ultraviolet absorbing layer. Next, lipoxy SP-
1509 (trade name, manufactured by Showa Polymer Co., Ltd.) was coated with a 20% by weight solution of isopropyl alcohol in which 4% by weight of lucirin TPO (trade name of BASF) was mixed with a bar coater so as to have a thickness of 5 μm. (500mJ
/ Cm ² ) and cured to form a hard coat layer, thereby obtaining an optical laminate of the present invention.

The accelerated light resistance test of the obtained optical laminate was performed using a xenon arc lamp type light resistance tester Santester CPS manufactured by Shimadzu Corporation with a sample surface irradiance of 100 W / m ² (wavelength range 300 to 700 nm) and a test time of 100. It was performed under the condition of time.

As a result of the test, when the reflection color of the optical laminate and the reflection color before the test were visually observed and compared, no difference was observed in the reflection color. Even after the accelerated light resistance test, the rainbow caused by the diffraction pattern was observed. Color coloring characteristics and selective reflection characteristics specific to cholesteric liquid crystals were maintained. Further, when the alignment state and the diffractive polarization effect of the cholesteric liquid crystal layer constituting the optical laminate were observed, no change was observed from the state before the test.

Next, a friction resistance test of the obtained optical laminate was performed using a friction tester FR-I type manufactured by Suga Test Instruments Co., Ltd. The laminate was fixed such that the protective layer was on the upper surface, a dry white cotton cloth was attached to the friction element, and a friction operation of 50 reciprocations was performed between 10 cm on the test piece for 50 seconds for 50 seconds. When the protective layer after the test was visually observed, almost no damage was found on the protective layer. The criterion for discoloration was 4.

Example 8 The cholesteric alignment surface of the cholesteric alignment film obtained in Reference Example 8 was combined with a diffraction surface of a ruled diffraction grating film (900 lines / mm) manufactured by Edmund Scientific Japan and a laminate. Of the cholesteric alignment film faces each other, and using a laminator DX-350 manufactured by Tokyo Laminex Co., Ltd., 1
Heating and pressing were performed under the conditions of 20 ° C., 0.3 MPa, and a roll contact time of 1 second (diffraction grating film / cholesteric alignment film / polyphenylene sulfide film). After cooling to room temperature, the diffraction grating film was removed.

Next, a commercially available adhesive made of a photocurable acrylic oligomer was applied to the cholesteric alignment film surface from which the diffraction grating film had been removed using a bar coater so as to have a thickness of 5 μm. Next, the glass substrate was bonded to the adhesive-coated surface of the film using a desktop laminator, and was irradiated with ultraviolet rays to cure the adhesive.

After the adhesive was cured, the end of the polyphenylene sulfide film used as the alignment substrate was held by hand, and the polyphenylene sulfide film was peeled off at 180 ° in the interface between the film and the cholesteric alignment film. Oriented film / adhesive layer /
The laminated body laminated | stacked in order of the glass substrate was obtained.

Observation of the surface of the cholesteric alignment film constituting the obtained laminate revealed that iridescence caused by the diffraction pattern and selective reflection peculiar to the cholesteric liquid crystal were clearly recognized. Also, when the orientation state of the cholesteric alignment film surface from which the diffraction grating film was removed was observed by a polarizing microscope and a transmission electron microscope of the liquid crystal layer cross section, the helical axis orientation in the cholesteric phase was not uniformly parallel to the film thickness direction. It was also confirmed that cholesteric alignment in which the helical pitch was not uniformly spaced in the film thickness direction was formed in the surface region of the liquid crystal layer. In other regions, it was confirmed that a cholesteric orientation in which the helical axis orientation was uniformly parallel to the film thickness direction and the helical pitch was uniformly uniform in the film thickness direction was formed. When a He-Ne laser (wavelength 632.8 nm) was perpendicularly incident on the cholesteric alignment film surface, laser light was observed at an emission angle of 0 ° and about ± 35 °. In order to further check the polarization characteristics, place the laminate obtained under normal indoor lighting and place a right circularly polarizing plate (transmitting only right circularly polarized light)
As a result, rainbow-colored reflected diffraction light was observed, which was almost the same as the brightness when observed without a polarizing plate. On the other hand, observation through a left circularly polarizing plate (transmitting only left circularly polarized light) revealed a dark field, and no iridescent reflected and diffracted light was observed.

From these results, it was confirmed that in the cholesteric alignment film constituting the laminate, a region exhibiting diffractive ability was formed in the film surface region, and that the diffracted light was right-handed circularly polarized light. From this, it was also found that the cholesteric alignment film constituting the laminate becomes a cholesteric liquid crystal layer which is a component of the present invention.

The photocurable acrylic oligomer Aronix M-240 was applied to the cholesteric liquid crystal layer surface of the laminate (cholesteric liquid crystal layer / adhesive layer / glass substrate).
(Product name of Toagosei Co., Ltd.) 20% by weight, M-3 manufactured by Toagosei Co., Ltd.
20 (trade name) 10% by weight and ultraviolet absorber Cyas
Orb UV-24 (manufactured by Scitech) was added with 5.0% by weight of an ultraviolet-curable adhesive (Aronix UV-3630 (trade name) manufactured by Toagosei Co., Ltd.) using a bar coater so as to have a thickness of 5 μm. Then, the layer was irradiated with ultraviolet rays and cured to form a protective layer having an ultraviolet absorbing property and a hard coat property, thereby obtaining an optical laminate of the present invention.

In the obtained optical laminate, even when the ultraviolet absorbing layer was laminated, the iridescent color caused by the diffraction pattern and the selective reflection peculiar to the cholesteric liquid crystal were clearly recognized as before the lamination of the absorbing layer. Was done.

(Example 9) An adhesive composed of a commercially available photocurable acrylic oligomer was applied to the cholesteric alignment surface of the cholesteric alignment film obtained in Reference Example 9 using a bar coater to a thickness of 5 µm. did. Next, a plastic substrate whose surface was covered with an aluminum thin film was bonded to the adhesive-coated surface of the film, and the film was irradiated with ultraviolet rays to cure the adhesive.

After the adhesive was cured, the end of the polyphenylene sulfide film used as the alignment substrate was held by hand, and the polyphenylene sulfide film was peeled off at 180 ° in the interface between the film and the cholesteric alignment film. Oriented film / adhesive layer /
A laminate in which aluminum thin films were laminated in this order was obtained.

Next, a ruled line diffraction grating film manufactured by Edmund Scientific Japan (900 / m)
m) The cholesteric alignment film surface of the laminate is overlapped so that the diffraction surface of m) faces each other, and heated and pressed at 120 ° C., 0.3 MPa, and a roll contact time of 1 second using a laminator DX-350 manufactured by Tokyo Laminex. (Diffraction grating film / cholesteric alignment film / adhesive layer / aluminum thin film). After cooling to room temperature, the diffraction grating film was removed. Observation of the cholesteric alignment film surface on which the diffraction grating film was superimposed revealed that iridescent color caused by the diffraction pattern and selective reflection peculiar to the cholesteric liquid crystal were clearly recognized. Also, when the orientation state of the cholesteric alignment film surface from which the diffraction grating film was removed was observed by a polarizing microscope and a transmission electron microscope of the liquid crystal layer cross section, the helical axis orientation in the cholesteric phase was not uniformly parallel to the film thickness direction. It was also confirmed that cholesteric alignment in which the helical pitch was not uniformly spaced in the film thickness direction was formed in the surface region of the liquid crystal layer. In other regions, it was confirmed that a cholesteric orientation in which the helical axis orientation was uniformly parallel to the film thickness direction and the helical pitch was uniformly uniform in the film thickness direction was formed. Also, He is placed vertically in the cholesteric alignment film plane.
When a -Ne laser (wavelength 632.8 nm) was incident, laser light was observed at an emission angle of 0 ° and about ± 35 °. In order to further confirm the polarization characteristics, the obtained laminate was placed under normal room illumination and observed through a right circularly polarizing plate (transmitting only right circularly polarized light). And the brightness when observed without a polarizing plate was almost the same. On the other hand, observation through a left circularly polarizing plate (transmitting only left circularly polarized light) revealed a dark field, and no iridescent reflected and diffracted light was observed.

From these results, it was confirmed that in the cholesteric alignment film constituting the laminate, a region having a diffractive ability was formed in the film surface region, and that the diffracted light was right-handed circularly polarized light. From this, it was also found that the cholesteric alignment film constituting the laminate becomes a cholesteric liquid crystal layer which is a component of the present invention.

An ultraviolet curable adhesive (Toagosei Co., Ltd.) in which 5.0% by weight of an ultraviolet absorber Cyasorb UV-24 (manufactured by Scitech) was added to the cholesteric liquid crystal layer surface of the laminate (cholesteric liquid crystal layer / adhesive layer / aluminum thin film). Aronix UV-3630 (trade name) manufactured by Co., Ltd. is diluted with M-111 (trade name) manufactured by the company, and the viscosity is 250 m.
Pa · s) with a bar coater to a thickness of 5 μm
Was applied, and was irradiated with ultraviolet rays and cured to form an ultraviolet absorbing layer. Next, an adhesive composed of a photo-curable acrylic oligomer in which fine silica (Aerosil R812 (trade name) manufactured by Nippon Aerosil Co., Ltd.) is dispersed is applied to the surface of the ultraviolet absorbing layer so as to have a thickness of 5 μm using a bar coater. Irradiation and curing of ultraviolet rays were performed to form a hard coat layer, and an optical laminate of the present invention was obtained.

The accelerated light resistance test of the obtained optical laminated body was performed using a xenon arc lamp type light resistance tester Santester CPS manufactured by Shimadzu Corporation with a sample surface irradiance of 100 W / m ² (wavelength range of 300 to 700 nm) and a test time of 100. It was performed under the condition of time.

As a result of the test, when the reflected color of the optical laminate and the reflected color before the test were visually observed and compared, no difference was observed in the reflected color, and even after the accelerated light resistance test, the rainbow caused by the diffraction pattern was observed. Color coloring characteristics and selective reflection characteristics specific to cholesteric liquid crystals were maintained. Further, when the alignment state and the diffractive polarization effect of the cholesteric liquid crystal layer constituting the optical laminate were observed, no change was observed from the state before the test.

Next, a friction resistance test of the obtained optical laminate was performed using a friction tester FR-I type manufactured by Suga Test Instruments Co., Ltd. The laminate was fixed such that the protective layer was on the upper surface, a dry white cotton cloth was attached to the friction element, and a friction operation of 50 reciprocations was performed between 10 cm on the test piece for 50 seconds for 50 seconds. When the protective layer after the test was visually observed, almost no damage was found on the protective layer. The criterion for discoloration was 4.

(Example 10) The cholesteric alignment surface of the cholesteric alignment film obtained in Reference Example 10 was combined with a diffraction surface of a ruled diffraction grating film (900 lines / mm) manufactured by Edmund Scientific Japan and a laminate. The cholesteric alignment film faces are stacked so that they face each other,
Using a laminator DX-350 manufactured by Tokyo Laminex, heating and pressing were performed under the conditions of 120 ° C., 0.3 MPa, and a roll contact time of 1 second (diffraction grating film / cholesteric alignment film / polyphenylene sulfide film). After cooling to room temperature, the diffraction grating film was removed.

Next, an adhesive made of a commercially available photocurable acrylic oligomer was applied to the cholesteric alignment film surface from which the diffraction grating film had been removed using a bar coater so as to have a thickness of 5 μm. Next, a plastic substrate covered with an aluminum thin film was adhered to the adhesive applied surface of the film using a desktop laminator, and irradiated with ultraviolet rays to cure the adhesive.

After the adhesive was cured, the end of the polyphenylene sulfide film used as the alignment substrate was held by hand, and the polyphenylene sulfide film was peeled off at 180 ° in the interface between the film and the cholesteric alignment film. Oriented film / adhesive layer /
A laminate in which aluminum thin films were laminated in this order was obtained.

When the surface of the cholesteric alignment film constituting the obtained laminate was observed, iridescence caused by the diffraction pattern and selective reflection peculiar to the cholesteric liquid crystal were clearly recognized. Also, when the orientation state of the cholesteric alignment film surface from which the diffraction grating film was removed was observed by a polarizing microscope and a transmission electron microscope of the liquid crystal layer cross section, the helical axis orientation in the cholesteric phase was not uniformly parallel to the film thickness direction. It was also confirmed that cholesteric alignment in which the helical pitch was not uniformly spaced in the film thickness direction was formed in the surface region of the liquid crystal layer. In other regions, it was confirmed that a cholesteric orientation in which the helical axis orientation was uniformly parallel to the film thickness direction and the helical pitch was uniformly uniform in the film thickness direction was formed. When a He-Ne laser (wavelength 632.8 nm) was perpendicularly incident on the cholesteric alignment film surface, laser light was observed at an emission angle of 0 ° and about ± 35 °. In order to further check the polarization characteristics, place the laminate obtained under normal indoor lighting and place a right circularly polarizing plate (transmitting only right circularly polarized light)
As a result, rainbow-colored reflected diffraction light was observed, which was almost the same as the brightness when observed without a polarizing plate. On the other hand, observation through a left circularly polarizing plate (transmitting only left circularly polarized light) revealed a dark field, and no iridescent reflected and diffracted light was observed.

From these results, it was confirmed that in the cholesteric alignment film constituting the laminate, a region exhibiting diffractive ability was formed in the film surface region, and that the diffracted light was right-handed circularly polarized light. From this, it was also found that the cholesteric alignment film constituting the laminate becomes a cholesteric liquid crystal layer which is a component of the present invention.

An ultraviolet curable adhesive (Toagosei Co., Ltd.) in which 5.0% by weight of an ultraviolet absorber Cyasorb UV-24 (manufactured by Scitech) was added to the cholesteric liquid crystal layer surface of the laminate (cholesteric liquid crystal layer / adhesive layer / aluminum thin film). Aronix UV-3630 (trade name) manufactured by Co., Ltd. is diluted with M-111 (trade name) manufactured by the company, and the viscosity is 250 m.
Pa · s) with a bar coater to a thickness of 5 μm
Then, the coating was applied, and the coating was irradiated with ultraviolet rays and cured to form an ultraviolet absorbing layer. Next, an adhesive composed of a photo-curable acrylic oligomer in which fine silica (Aerosil R812 (trade name) manufactured by Nippon Aerosil Co., Ltd.) is dispersed is applied to the surface of the ultraviolet absorbing layer so as to have a thickness of 5 μm using a bar coater. Irradiation and curing of ultraviolet rays were performed to form a hard coat layer, and an optical laminate of the present invention was obtained.

The obtained optical laminate was obtained by laminating a protective layer comprising an ultraviolet absorbing layer and a hard coat layer.
As before the protective layer was laminated, iridescent color caused by the diffraction pattern and selective reflection peculiar to the cholesteric liquid crystal were clearly recognized.

(Comparative Example 1) Ultraviolet absorber Cyasorb
A laminate was obtained in the same manner as in Example 1, except that UV-24 (manufactured by Scitech) was not added.

In the obtained optical laminate, iridescent color caused by the diffraction pattern and selective reflection peculiar to the cholesteric liquid crystal were clearly recognized.

When an accelerated light resistance test was conducted in the same manner as in Example 1, after the test, both the reflected color and the iridescent color had disappeared to such an extent that almost no color was recognized.

Comparative Example 2 A laminate was obtained in the same manner as in Example 1 except that M-315 was not added.

In the obtained optical laminate, iridescent color caused by the diffraction pattern and selective reflection peculiar to the cholesteric liquid crystal were clearly recognized.

When the abrasion resistance test was carried out in the same manner as in Example 1, the surface after the test was conspicuous with scratches and the whole was in a whitish hazy state, and the criteria for judging discoloration were 2-3. There was a large difference in reflected light between before and after the test.

[0145]

The optical laminate of the present invention has unique optical characteristics such as diffracted light having a circular polarization property not found in conventional optical elements, and its application range is extremely wide as a diffraction function element. For example, it can be suitably used as an optical member such as an optical element, an optoelectronic element, a decoration material, and a forgery prevention element.

Further, the optical laminate of the present invention is excellent in various resistances such as light resistance and abrasion resistance without deteriorating unique optical characteristics, so that it can be applied to various applications. The industrial value is extremely high.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H049 AA39 AA43 BA03 BA05 BA45 BB13 BB22 BB51 BB62 BC09 BC22 CA05 CA15 CA22 CA28 2H088 EA48 EA65 GA03 GA06 MA20 4F100 AR00B AR00C AT00A BA10A BA10C GB90 JA11B JC14K

Claims (2)

[Claims] 1. A laminate comprising at least a support substrate / adhesive layer / cholesteric liquid crystal layer / protective layer, wherein the cholesteric liquid crystal layer has at least a part of the cholesteric liquid crystal film having a region exhibiting a diffractive ability. An optical laminate wherein the protective layer has an ultraviolet absorbing property and a hard coat property. 2. The optical laminate according to claim 1, wherein the protective layer is formed from at least two layers of an ultraviolet absorbing layer and a hard coat layer.