JP2000309198A - Element for transfer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an element for transfer formed of a new liquid crystal film by which a diffraction light itself can generate a specific polarization such as a circular polarization or a linear polarization. SOLUTION: This element for transfer in formed of a cholesteric liquid crystal film which is a laminated body constituted at least of a supporting base/a cholesteric liquid crystal layer/an adhesive layer, and the cholesteric liquid crystal layer has a region showing a diffraction capability at least on one section in the film thickness direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transfer element 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. In more detail, the cholesteric liquid crystal layer, which has a new property called diffractive power in addition to the selective reflection characteristics and circular polarization characteristics unique to cholesteric liquid crystals, can be easily applied to the transferred object, and the cholesteric liquid crystal layer can have disordered alignment and cracks. The present invention has led to the invention of a transfer element capable of performing transfer without occurrence of image formation.

[0005]

That is, the present invention provides a laminate comprising at least a support substrate / a cholesteric liquid crystal layer / an adhesive layer, wherein the cholesteric liquid crystal layer comprises
The present invention relates to a transfer element composed of a cholesteric liquid crystal film having a region exhibiting a diffractive power in part.

[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 / cholesteric liquid crystal layer / adhesive layer. Here, the term “support substrate / cholesteric liquid crystal layer / adhesive layer” means a configuration in which a support substrate, a cholesteric liquid crystal layer, and an adhesive layer are laminated in this order. Note that an intermediate layer may be provided between the support substrate and the cholesteric liquid crystal layer,
For example, an adhesive layer, a release layer, or the like can be used as the intermediate layer. Hereinafter, components of the present invention will be described in order.

The support substrate, which is a component of the present invention, functions as a support for the cholesteric liquid crystal layer. After the cholesteric liquid crystal layer has been transferred to the object to be transferred,
The support substrate is separated and removed. As a supporting substrate having such a function, for example, polyimide, polyamide imide, polyamide, polyether imide, polyether ether ketone, polyether ketone, polyketone sulfide, polyether sulfone, polysulfone, polyphenylene sulfide, polyphenylene oxide, polyethylene terephthalate , Polybutylene terephthalate, polyethylene naphthalate, polyacetal, polycarbonate, polyarylate, acrylic resin, epoxy resin, phenolic resin, polyvinyl alcohol, cellulosic plastics, polyethylene,
Plastic films and sheets formed of a chain or alicyclic polyolefin such as polypropylene, poly (4-methyl-1-pentene), norbornene-based resin, and the like are included. As the support substrate, various alignment support substrates that can be used in forming a cholesteric liquid crystal film described later can be used as they are.

As the supporting substrate, a plastic film or sheet having a surface treated with silicon or the like, or an acrylic resin, a methacrylic resin, an epoxy resin, or a paraffin-based wax may be used as the supporting substrate. it can. Further, a plastic film or sheet serving as a support substrate that has been subjected to physical deformation treatment such as embossing, hydrophilic treatment, hydrophobic treatment, or the like may be used as a support substrate which is a component of the present invention. it can.

The thickness of the supporting substrate is usually 8 to 200 μm,
Preferably from 15 to 150 μm, more preferably from 20 to
100 μm. If the thickness is less than 8 μm, the handling properties of the obtained transfer element may be deteriorated. If the thickness is larger than 200 μm, the peeling transfer operation may not be performed smoothly. Note that the support substrate is removed when the cholesteric liquid crystal layer is transferred to the transfer target, and the separation interface is usually between the interface between the support substrate and the protective layer.

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 the cholesteric orientation is fixed 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 effect and the like, it is possible to select which film surface is to be the adhesive layer side constituting the transfer element 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, preferably 30% or less with respect to the film thickness of the cholesteric liquid crystal film. More preferably, it is desirable to be formed in a layer state having a thickness of 10% or less. When the thickness of the layer (region) exhibiting the diffractive ability exceeds 50%, the effects such as the selective reflection characteristic and the circular polarization characteristic caused by the cholesteric liquid crystal phase are reduced, and the unique optical characteristic which is a component of the present invention is reduced. The effect of the cholesteric liquid crystal layer shown 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 heat is applied. Alternatively, a method of transferring the diffraction pattern of the diffraction element substrate to a cholesteric alignment film by applying pressure, or after cholesteric alignment of a polymer liquid crystal or a low-molecular liquid crystal or a mixture thereof using the diffraction element substrate as an alignment substrate, and then changing its 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" used herein includes 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 of 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 it can fix the cholesteric orientation, 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 a basic skeleton of 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 having a cholesteric alignment fixed without a region exhibiting a diffraction ability, 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 film material such as a bisazide compound or a bisazide compound may be used as long as it does not hinder the development of a cholesteric phase in addition to a polymer liquid crystal or a low molecular weight liquid crystal. A cross-linking agent such as glycidyl methacrylate can be added, and by adding these cross-linking agents, cross-linking can be performed with a cholesteric phase developed. Further, various additives such as dichroic dyes, dyes and pigments may be appropriately added to the film material 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 effect of the cholesteric liquid crystal layer exhibiting unique optical characteristics, which is a component 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 adhesive layer, which is a component of the present invention, is formed for the purpose of bonding between the object to be transferred and the cholesteric liquid crystal layer. The adhesive layer is not particularly limited, and various conventionally known adhesives and adhesives, specifically, a hot-melt adhesive, a light or electron beam-curable reactive adhesive, or the like may be appropriately used. Can be. Among them, a hot-melt adhesive is preferably used in the present invention from the viewpoint of workability during transfer.

The hot melt type adhesive is not particularly limited, but the working temperature of the hot melt is 250 ° C. or lower, preferably 80 to 200 ° C., more preferably 100 to 16 ° C.
Those having a temperature of about 0 ° C. are 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 A hot melt adhesive having a base resin of petroleum resin, terpene resin, rosin resin or the like can be used.

As the reactive adhesive, a prepolymer and / or a monomer having photo- or electron-beam polymerizability, if necessary, other monofunctional monomers, polyfunctional monomers, various polymers, stabilizers, photopolymerizable Those containing an initiator, 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 light 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 the like, 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 the curing power of the electron beam, and cannot be determined unconditionally. Usually, curing can be carried out by irradiating under an acceleration voltage of 50 to 1000 kV, preferably 100 to 500 kV.

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 of forming the adhesive layer varies depending on the method of manufacturing the transfer element described below. For example, a roll coating method, a die coating method, a bar coating method, a curtain coating method, an extrusion coating method, a gravure roll It can be formed on a cholesteric liquid crystal layer or the like by using a known method such as a coating method, a spray coating method, and a spin coating method.

An intermediate layer may be provided between the cholesteric liquid crystal layer and the supporting substrate constituting the transfer element of the present invention. Examples of the intermediate layer include an adhesive layer and a release layer.

The adhesive layer is not particularly limited, but, for example, the above-described light or electron beam-curable reactive adhesive can be appropriately used. The release layer can be formed of, for example, wax, silicone, a fluorine-based release agent, or the like, which exhibits fluidity by heat. Incidentally, between the support substrate and the cholesteric liquid crystal layer constituting the transfer element of the present invention, two layers of an adhesive layer and a release layer may be formed as an intermediate layer.

The method for producing the transfer element 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)
Prepare the remaining laminated body separately prepared on the support substrate on the peelable substrate, remove the peelable substrate by transferring to the support substrate side by means of pressure, heating, curing, etc. alone or in combination. A method of forming an adhesive layer on a cholesteric liquid crystal layer serving as an outer layer.

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 an adhesive layer on the cholesteric liquid crystal film layer,
(2) The cholesteric liquid crystalline film formed on the alignment substrate is transferred onto a second substrate different from the alignment substrate via an adhesive layer, and the alignment substrate is peeled off. Then, after forming an adhesive layer on a support substrate or a cholesteric liquid crystal film on which an adhesive layer has been formed in advance, transferring the cholesteric liquid crystal film to the support substrate, and peeling and removing only the second substrate from the cholesteric liquid crystal film, A method of forming an adhesive layer on the cholesteric liquid crystal film, (3) transferring the cholesteric liquid crystal film formed on the alignment substrate to a second substrate different from the alignment substrate via the adhesive layer, and Peel and remove. Next, the cholesteric liquid crystal film is transferred onto the third substrate via the adhesive layer, 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 third substrate is peeled off and removed.
A method of forming an adhesive layer on a cholesteric liquid crystal film, and the like.

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 and the removable substrate are bonded via an adhesive, the releasability can be removed at the interface between the adhesive layer 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. What formed the thin film or the inorganic thin film, what performed the chemical treatment, and what performed the physical treatment such as surface polishing for vapor deposition can also be used.

The adhesive used for transferring the cholesteric liquid crystal film to the removable substrate is not particularly limited, but is preferably a heat, light or electron beam-curable type as described above. A reactive adhesive or the like can be used as appropriate.

Further, examples of the peeling and removing method in the above manufacturing method include a method of attaching an adhesive tape to a corner end of an oriented substrate or a removable substrate and artificially peeling, 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 transfer element of the present invention is not limited thereto.

The transfer element of the present invention depends on the type of the adhesive layer constituting the element. For example, polyimide, polyamideimide, polyamide, polyetherimide, polyetheretherketone, polyetherketone, polyketonesulfide , Polyether sulfone, polysulfone, polyphenylene sulfide, polyphenylene oxide, polyvinyl chloride, polystyrene, polypropylene, polymethyl methacrylate, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polycarbonate, polyvinyl alcohol, polyacetal, polyarylate, cellulose-based plastic Sheet, film or various molded products of paper, epoxy resin, phenolic resin, etc., paper such as paper and synthetic paper, metal Easily from the supporting substrate without causing alignment disturbance or cracking the cholesteric liquid crystal layer for different transfer target such as glass, also it can be transcribed in a desired shape. When a hot-melt adhesive is used as the adhesive which is a component of the present invention, heating, pressing,
When a so-called hot stamping device capable of instantaneously applying an impact is used, a series of operations of transfer, peeling and removal can be performed simultaneously and instantaneously.

The transfer element of the present invention can transfer a cholesteric liquid crystal layer having a unique effect that a diffracted light has a circular polarization property, which is not possible with a conventional optical member, to an object to be transferred. Due to this unique effect, for example, by transferring the cholesteric liquid crystal layer to a spectroscopic optical device such as an ellipsometer that requires polarized light, the light use efficiency can be extremely increased. 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 the reflection at the interface occurs, resulting in extremely low light utilization efficiency. By transferring the cholesteric liquid crystal layer to a desired portion, the light use efficiency is extremely high, and it is theoretically possible to use about 100%. The transmission and blocking of diffracted light in the cholesteric liquid crystal layer constituting the transfer element of the present invention can be easily controlled by using an ordinary polarizing plate. Normally, diffracted light having no polarization cannot be completely blocked by any combination of polarizing plates. That is, in the cholesteric liquid crystal layer that is a component of the transfer element of the present invention, for example, diffracted light having right polarization can be completely blocked only when a left circular polarizer is used, and other polarizers can be used. Even if used, complete interruption cannot be realized. Due to such a unique effect, for example, in an environment where 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 It can be eliminated.

As described above, the transfer element of the present invention can easily transfer a cholesteric liquid crystal layer to an object to be transferred, and the transferred cholesteric liquid crystal layer has a very wide application range as a new diffraction function element. Can be used as various optical elements, optoelectronic elements, decorative members, forgery prevention elements, and the like.

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 transferring the cholesteric liquid crystal layer to an acrylene film (manufactured by Mitsubishi Rayon Co., Ltd.) using the transfer element of the present invention, and obtaining an optical laminate, it is possible to develop it for various optical applications. . For example, the optical laminated body is formed of a TN (twisted nematic) -LCD (L
liquid Crystal Display), ST
N (Super Twisted Nematic) -L
CD, ECB (Electrically Contr
old Birefringence) -LCD,
OMI (Optical Mode Interferer)
ence) -LCD, OCB (Optically C)
Ompensated Birefringence)
-LCD, HAN (Hybrid Aligned N)
ematic) -LCD, IPS (In Plane)
By providing a liquid crystal display such as a (Switching) -LCD, various LCDs with improved color compensation and / or improved viewing angle can be obtained. 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. .

As a decorative member, a cholesteric liquid crystal layer can be transferred to various products and the like as a new member having a combination of iridescent coloring effect by diffractive power and colorful coloring effect by cholesteric liquid crystal. In addition, since the cholesteric liquid crystal layer can be easily transferred, it can be expected to greatly contribute to differentiation from other similar products by methods such as attachment to existing products and integration. For example, when the cholesteric liquid crystal layer of the present invention incorporating a diffractive pattern having a design is transferred to a glass window or the like, the selective reflection specific to the cholesteric liquid crystal with 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, etc. having both the anti-counterfeit effect of the diffraction element and the cholesteric liquid crystal. Specifically, using the transfer element of the present invention, for example, a car driver's license, identification card, passport, credit card, prepaid card, various cash vouchers,
The cholesteric liquid crystal layer is integrated with or partially provided on the card substrate, the mount, etc. by transferring it to a card substrate, a mount, etc. of gift cards, securities, etc., specifically, attached, embedded, or woven into paper. be able to. Further, the cholesteric liquid crystal layer constituting the transfer element of the present invention has a region exhibiting diffractive power in a part of the cholesteric liquid crystal layer, and also has a wavelength-selective reflectivity, a circularly-polarized light selective reflectivity, and color It has both viewing angle dependence and the effect of exhibiting a beautiful cholesteric color. Therefore, when the cholesteric liquid crystal layer which is a component of the transfer element of the present invention is used as a forgery prevention element, it is extremely difficult to forge the cholesteric liquid crystal layer. In addition to the anti-counterfeiting effect, it also has an iridescent color effect of the diffraction element and a vivid color effect of the cholesteric liquid crystal, and thus has excellent design properties. From these facts, the cholesteric liquid crystal layer constituting the transfer element of the present invention is very useful as a forgery prevention element.

These applications are only examples, and the transfer element of the present invention can be used for various applications in which 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, the cholesteric liquid crystal layer exhibiting its unique optical effect can be easily transferred to various applications other than the above-mentioned applications, and the liquid crystal layer can be transferred without disordered alignment, cracks, etc. Application development is possible in various applications.

[0047]

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 low-molecular liquid crystal having acryloyl group Distilled and purified tetrahydrofuran 180
g, 151.3 g (518 mmol) of 4- (6-acryloyloxyhexyloxy) benzoic acid and 1.5 g of 2,6-ditert-butyl-4-methylphenol were dissolved in 70.1 g of diisopropylethylamine.
(543 mmol) was added dropwise with stirring to a solution of 62.1 g (543 mmol) of methanesulfonyl chloride in tetrahydrofuran, which was cooled to -10 ° C. After completion of the dropwise addition, the reaction solution was heated to 0 ° C. and further stirred, and then 29.87 g of methylhydroquinone (24
(6 mmol) in tetrahydrofuran was added dropwise. The reaction solution was further stirred, and 4-dimethylaminopyridine was added.
0 g (25 mmol) of triethylamine 62.4 g
(617 mmol) was added dropwise. After the dropwise addition, the reaction solution was stirred at 0 ° C. for 1 hour, and then heated to room temperature and stirred for 5 hours. After completion of the reaction, the reaction solution was diluted with 1000 ml of ethyl acetate, transferred to a separating funnel, and separated with 1N hydrochloric acid. The organic layer was further diluted with 1N hydrochloric acid, a saturated aqueous solution of sodium hydrogencarbonate, and a saturated aqueous solution of magnesium sulfate. Washed. 100 g of anhydrous magnesium sulfate was added to the organic layer, and the mixture was stirred at room temperature for 1 hour, dehydrated and dried. The magnesium sulfate was separated by filtration, and concentrated by a rotary evaporator to obtain methylhydroquinone-bis (4- (6-acryloyloxythiol). Hexyloxy) benzoic acid ester was obtained as a crude product. The crude product was recrystallized from ethyl acetate / methanol to obtain 146.9 g of methylhydroquinone-bis (4- (6-acryloyloxyoxyhexyloxy) benzoic acid) ester as white crystals (yield 85. 2%). The purity by GPC of the compound I-1 was 98.7%. GPC uses tetrahydrofuran as an elution solvent, and is packed with a high-speed GPC packed column (TSK
gel G-1000HXL)
C analyzer CCP & 8000 (CP-8000, CO-
8000, UV-8000).

The obtained methylhydroquinone-bis (4-
(6-Acryloyloxy hexyloxy) benzoic acid)
When the ester was observed on a Mettler hot stage under a polarizing microscope, the ester changed to a crystalline phase at room temperature and a nematic phase at around 85 ° C., and became an isotropic phase at around 115 ° C. upon further heating.

Reference Example 2 Using the same procedure as in Reference Example 1, 34- (6-acryloyloxyoxyhexyloxy) benzoic acid was obtained from 32.5 g (111 mmol) and 4-cyanophenol 12.6 g (106 mmol) by 34 There was obtained 0.8 g of 4-cyanophenol-4- (6-acryloyloxyoxyhexyloxy) benzoate (yield 84%). The purity of 4-cyanophenol-4- (6-acryloyloxyohexyloxy) benzoate by GPC was 99.3%.

Reference Example 3 Synthesis of Polymer Liquid Crystal: 49 mmol of terephthalic acid, 24 mmol of methylhydroquinone,
Catechol 25 mmol, (R) -2-methyl-1,4
Polycondensation was carried out using 1.7 mmol of butanediol and 100 mg of sodium acetate in a nitrogen atmosphere at 180 ° C. for 1 hour, 200 ° C. for 1 hour, and 250 ° C. for 1 hour in a stepwise manner. Then while flowing nitrogen 2
The polycondensation was continued at 50 ° C. for 2 hours,
Time polycondensation was performed. After dissolving the obtained polymer in tetrachloroethane, reprecipitation was performed with methanol to obtain a purified polymer (aromatic polyester). The logarithmic viscosity of the obtained polymer was 0.150, and the glass transition point was 90 ° C.

The analytical methods of the obtained polymer 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.

(Example 1) 7.0 g of methylhydroquinone-bis (4- (6-acryloyloxyoxyhexyloxy) benzoic acid) ester obtained in Reference Example 1 and 4-cyanophenol obtained in Reference Example 2 -4- (6-Acryloyloxyoxyhexyloxy) benzoic acid ester to 1.07
g, 1.93 g of chiral dopant liquid crystal S-811 (manufactured by Roddick), 1.5 mg of fluorinated surfactant S-383 (manufactured by Asahi Glass Co., Ltd.), and Irgacure 907 (Ciba-Geigy), which is a photopolymerization initiator 3% by weight based on the acryloyl group-binding compound with N-methyl-
A 10% by weight solution of 2-pyrrolidone was prepared. This N-
Rubbed methyl-2-pyrrolidone solution thickness 7
A 5 μm polyethylene terephthalate film (manufactured by Toray Industries, Inc.) is applied, the solvent is dried, and heat treatment is performed at 80 ° C. to align the liquid crystal molecules. A film was obtained.

When the transmission spectrum of the obtained film was evaluated using a spectroscope V-500 (manufactured by JASCO Corporation),
A reduced region of transmitted light due to selective reflection was observed around 780 nm near the infrared region, and it was confirmed that this film was a cholesteric alignment film showing selective reflection of red light.

On the obtained cholesteric alignment film, a ruled line diffraction grating film (900 ruled lines / mm) manufactured by Edmund Scientific Japan Co., Ltd. was superposed so that the liquid crystal surface and the diffraction surface faced each other. Using a laminator DX-350 manufactured by Laminex, at 150 ° C.
After heating and pressurizing under the conditions of 3 MPa and a roll contact time of 0.5 seconds, the resultant was cooled to room temperature, and then the ruled-type diffraction grating film was removed.

Observation of the cholesteric alignment film surface on which the diffraction grating film was superimposed revealed clear iridescence caused by the diffraction pattern and selective reflection characteristic of the cholesteric liquid crystal. 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, a region exhibiting a diffractive ability was formed in the film surface region, and that the diffracted light was right circularly polarized light. From this, it was found that this cholesteric alignment film becomes a cholesteric liquid crystal layer which is a component of the present invention. Next, a hot melt adhesive layer was formed on the cholesteric liquid crystal layer from which the diffraction grating film had been removed to obtain a transfer element.

The obtained transfer element was transferred at 140 ° C. on a 10 cm square, 1 mm thick plastic sheet made of polyvinyl chloride using a hot stamping device.
As a result, a cholesteric liquid crystal layer of about 1 cm square was transferred to the right corner of the polyvinyl chloride sheet. The polyethylene terephthalate film, which is a support substrate of the transfer element, was separated from the cholesteric liquid crystal layer during hot stamping. The adhesive layer was firmly bonded to the polyvinyl chloride sheet. When light was applied to the cholesteric liquid crystal layer after transfer, bright selective reflection light and diffracted light were observed as in the case before transfer.

(Embodiment 2) Rubbed 75 μm thick
m polyphenylene sulfide film (Toray Industries, Inc.)
2) of the aromatic polyester obtained in Reference Example 3
A 0% by weight N-methyl-2-pyrrolidone solution was applied by a spin coating method, dried, and heat-treated at 200 ° C. for 5 minutes to obtain a film exhibiting a golden selective reflection. When the reflected light of the film was measured, it was confirmed that the film was a cholesteric alignment film having a center wavelength of about 600 nm and a selective reflection wavelength bandwidth of 100 nm.

Next, on the cholesteric alignment film layer, a scored diffraction grating film (900 scored lines / mm) manufactured by Edmund Scientific Japan was used.
Laminated so that the liquid crystal surface and diffraction surface of the film face each other,
Using a laminator DX-350 manufactured by Tokyo Laminex Co., Ltd., heating and pressing were performed under the conditions of 120 ° C., 0.3 MPa, and a roll contact time of 0.5 second, and after cooling to room temperature, the scored diffraction grating film was removed.

Observation of the cholesteric alignment film surface on which the diffraction grating film was superimposed revealed clear iridescence caused by the diffraction pattern and selective reflection characteristic of the cholesteric liquid crystal. 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, 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 found that this cholesteric alignment film becomes a cholesteric liquid crystal layer which is a component of the present invention.

Next, a hot-melt adhesive layer was formed on the film surface from which the diffraction grating film had been removed, thereby producing a transfer element. This transfer element was 10 cm square and 1 m thick.
m was transferred onto a polyvinyl chloride plastic sheet at 140 ° C. using a hot stamping device. As a result, a 1 cm square cholesteric liquid crystal layer could be transferred to the right corner of the polyvinyl chloride plastic sheet. The polyphenylene sulfide film, which is a support substrate of the transfer element, was separated from the cholesteric liquid crystal layer during hot stamping. The adhesive layer was firmly bonded to the polyvinyl chloride sheet.

When light was applied to the cholesteric liquid crystal layer after the transfer, bright selective reflected light and diffracted light were observed as in the case before the transfer. When the transfer element was used to transfer the cholesteric liquid crystal layer onto A4 size paper, the alignment of the cholesteric liquid crystal layer was disturbed or cracked in the same way as when the polyvinyl chloride sheet was used as the transfer object. The transfer was able to be performed without occurrence of blemishes. In the transferred cholesteric liquid crystal layer, bright selective reflected light and diffracted light were observed as in the case before the transfer.

Example 3 In the same manner as in Example 2, a cholesteric alignment film exhibiting a gold selective reflection was obtained on a rubbed polyphenylene sulfide film. Next, a lamination type diffraction grating film (900 rulings / mm) manufactured by Edmund Scientific Japan Co., Ltd. is stacked so that the liquid crystal surface and the diffraction surface of the film face each other, and using a laminator DX-350 manufactured by Tokyo Laminex, 12
After heating and pressurizing under the conditions of 0 ° C., 0.3 MPa, and a roll contact time of 0.5 second, the resultant was cooled to room temperature, and the scored diffraction grating film was removed.

Next, an adhesive layer made of an acrylic resin is formed on the film surface from which the diffraction grating film has been removed,
A transfer element was prepared. The obtained transfer element is 1 cm
It was cut into a corner size and bonded to a glass plate via an adhesive layer. Next, a cellophane tape was adhered to a polyphenylene sulfide film as a support substrate of the transfer element, and the polyphenylene sulfide film was peeled off.

When light was applied to the cholesteric liquid crystal layer after the transfer, diffracted light was observed simultaneously with the selectively reflected light. This also confirmed that the cholesteric liquid crystal layer had a diffractive ability. In addition, it was confirmed that the obtained transfer element could be similarly applied to transfer to a polyvinyl chloride sheet or paper.

[0068]

According to the present invention, there is provided a cholesteric liquid crystal layer comprising a cholesteric liquid crystal film having a unique characteristic, such as diffracted light having a circular polarization property, which is not present in conventional optical elements. The liquid crystal layer has a very wide application range as a new diffraction function element, and is useful as, for example, an optical element, an optoelectronic element, a decoration material, a forgery prevention element, and the like. Further, the transfer element of the present invention can be easily transferred to an object to be transferred without impairing the characteristics of the cholesteric liquid crystal layer exhibiting unique optical characteristics, and has excellent workability. For this reason, the transfer element of the present invention has extremely high industrial value, for example, it can impart various materials with the unique optical characteristics of the cholesteric liquid crystal layer.

Claims (1)

[Claims] 1. A transfer body comprising at least a support substrate / cholesteric liquid crystal layer / adhesive layer, wherein the cholesteric liquid crystal layer is formed of a cholesteric liquid crystal film partially having a diffractive region. element.