JP2000310714A - Method for producing polarization diffraction film - Google Patents

Abstract

(57) [Problem] To provide a new film in which diffracted light itself can generate specific polarized light such as circularly polarized light or linearly polarized light. SOLUTION: The weight average molecular weight Mw measured by GPC (in terms of polystyrene) is 1,000 to 100,000, the molecular weight distribution (Mw / Mn; Mn is the number average molecular weight) is 5 or less, and the logarithmic viscosity is 0.05 to 2.0 ( 0.5 g concentration in a phenol / tetrachloroethane (60/40 by weight) mixed solvent
/ Dl (temperature 30 ° C)) and a glass transition temperature (Tg) of 2
100 ° C. or less, and the transition temperature from the liquid crystal phase to the isotropic phase (T
a) a cholesteric alignment film formed from a film material containing a polymer liquid crystal as an essential component and having a temperature of 40 to 300 ° C. and a pressure of 0.05 to 80 MPa; A method for producing a polarizing diffraction film, wherein the diffraction pattern is transferred to form a region exhibiting diffractive ability in a part of the cholesteric alignment film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel method for producing a film capable of generating diffracted light having a polarizing 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 transfers a diffraction pattern of a diffraction element substrate under specific conditions using a polymer liquid crystal having specific physical properties as a film material. As a result, a region having diffractive power was successfully formed in a part of the film, and a new film was developed. More specifically, the inventors have invented a method for producing a polarized light diffractive film in which a new characteristic called diffractive ability is provided in addition to the selective reflection characteristic and the circularly polarized light characteristic characteristic of cholesteric liquid crystal.

[0005]

That is, the present invention provides a GP
Weight average molecular weight Mw measured in C (polystyrene conversion)
Is 1000 to 100,000, the molecular weight distribution (Mw / Mn; Mn is the number average molecular weight) is 5 or less, and the logarithmic viscosity is 0.05 to 2.0.
(Phenol / tetrachloroethane (weight ratio 60/4)
0) Concentration of 0.5 g / dl (temperature 30
C)), a cholesteric film formed from a film material containing, as an essential component, a polymer liquid crystal having a glass transition temperature (Tg) of 200 ° C or lower and a transition temperature (Ti) from a liquid crystal phase to an isotropic phase of 40 ° C or higher. Temperature of 40 to 30
The present invention relates to a method for producing a polarization diffraction film that transfers a diffraction pattern of a diffraction element substrate under a heating and pressurizing condition of 0 ° C. and a pressure of 0.05 to 80 MPa, and forms a region exhibiting diffractive ability in a part of a cholesteric alignment film.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. The polarizing diffraction film of the present invention is manufactured by transferring a diffraction pattern of a diffraction element substrate to a cholesteric alignment film formed from a film material containing a polymer liquid crystal having specific physical properties as an essential component under specific conditions. .

The polymer liquid crystal used in the present invention is GP
Weight average molecular weight Mw measured in C (polystyrene conversion)
Is 1000 to 100,000, the molecular weight distribution (Mw / Mn; Mn is the number average molecular weight) is 5 or less, and the logarithmic viscosity is 0.05 to 2.0.
(Phenol / tetrachloroethane (weight ratio 60/4)
0) Concentration of 0.5 g / dl (temperature 30
° C)), the glass transition temperature (Tg) is 200 ° C or lower, and the transition temperature (Ti) from the liquid crystal phase to the isotropic phase is 40 ° C or higher. When the weight average molecular weight (Mw) of the polymer liquid crystal measured by GPC (in terms of polystyrene) is less than 1,000, the resulting liquid crystalline film has low mechanical strength, which is not desirable in various post-processing steps and practical performance. If it exceeds 100,000, the fluidity of the liquid crystal deteriorates, which may adversely affect the alignment. On the other hand, if the molecular weight distribution exceeds 5, the meltability at the time of producing a cholesteric liquid crystalline film and the solubility in a solution become poor, and uniform orientation to a cholesteric phase is difficult to obtain, which may cause a practical problem. If the logarithmic viscosity is less than 0.05, the mechanical strength of the cholesteric liquid crystal film may be low, which is not desirable in various post-processes and practical performance. On the other hand, if it exceeds 2.0, the fluidity of the liquid crystal deteriorates, and it may be difficult to obtain a uniform alignment to the cholesteric phase.
Further, when the glass transition temperature (Tg) is higher than 200 ° C., the fluidity in the liquid crystal state is poor, and it may be difficult to obtain uniform alignment. Further, if necessary, it is difficult to select a support substrate used for alignment. May also occur. Further, when the transition temperature (Ti) from the liquid crystal phase to the isotropic phase is lower than 40 ° C., the alignment stability of the cholesteric liquid crystal film around room temperature may be undesirably deteriorated.

[0008] The polymer liquid crystal used in the present invention is not particularly limited as long as it satisfies the above-mentioned various physical properties, and any of a main chain type and a side chain type polymer liquid crystal may be used. Can be. 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. Preferred examples of the constituent unit of the polymer include an aromatic or aliphatic diol unit, an aromatic or aliphatic dicarboxylic acid unit, and an aromatic or aliphatic hydroxycarboxylic acid unit.

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

The cholesteric alignment film used in the present invention is formed from a film material containing the above-mentioned polymer liquid crystal as an essential component. The cholesteric alignment film can be obtained, for example, by applying a film material on a support substrate or an alignment film formed on the substrate and performing a heat treatment.

The support substrate used for obtaining the cholesteric alignment film is not particularly limited as long as it does not inhibit cholesteric alignment, and examples thereof include a glass substrate or a plastic substrate such as a plastic film or a plastic sheet. . As the glass substrate, for example, soda glass, silica-coated soda glass, borosilicate glass substrate, or the like can be used. As the plastic substrate, a polymethyl methacrylate, polystyrene, polycarbonate, polyether sulfone, polyphenylene sulfide, amorphous polyolefin, triacetyl cellulose, polyethylene terephthalate, polyethylene naphthalate substrate, or the like can be used. A uniaxial or biaxial stretching operation can be appropriately applied to these supporting substrates as needed. Further, the substrate may be subjected to a surface treatment such as a hydrophilization treatment, a hydrophobization treatment, and an easy peeling treatment. As the support substrate, one type alone or a laminate of two or more types of substrates can be used as the support substrate.

As the alignment film, a rubbed polyimide film is preferably used, but other alignment films known in the art can also be used as appropriate. Also, a plastic substrate or the like obtained by directly imparting an orientation ability by a rubbing treatment without applying polyimide or the like can be used when obtaining a cholesteric orientation film. The method of the alignment treatment is not particularly limited, but any method may be used as long as the liquid crystal molecules are uniformly aligned in parallel with the alignment treatment interface.

Next, as a means for applying a film material on the alignment film, there are melt coating and solution coating, but a solution coating is preferable in the process.

In the solution application, a film material is dissolved in a solvent at a predetermined ratio to prepare a solution having a predetermined concentration. As the solvent, although it varies depending on the type of film material to be used, usually, hydrocarbons such as toluene, xylene, butylbenzene, tetrahydronaphthalene, and decahydronaphthalene, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, propylene glycol dimethyl ether, ether such as tetrahydrofuran, Ketones such as methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, ethyl acetate, butyl acetate, ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate, ethyl lactate, γ
-Esters such as butyrolactone, amides such as N-methyl-2-pyrrolidone, dimethylformamide and dimethylacetamide, halogenated hydrocarbons such as dichloromethane, carbon tetrachloride, tetrachloroethane and chlorobenzene, butyl alcohol, triethylene glycol, Alcohols such as diacetone alcohol and hexylene glycol can be used. If necessary, two or more of these solvents can be used as a mixture. The concentration of the solution depends on the molecular weight and solubility of the polymer liquid crystal used,
Further, since it depends on the final film thickness of the target film and the like, it cannot be said unconditionally, but it is usually 1 to 60% by weight, preferably 3 to 40% by weight.

Further, a surfactant or the like may be added to the solution to facilitate application. Examples of the surfactant include cationic surfactants such as imidazoline, quaternary ammonium salts, alkylamine oxides, and polyamine derivatives, polyoxyethylene-polyoxypropylene condensates, primary and secondary alcohol ethoxylates. , Alkylphenol ethoxylates, polyethylene glycols and esters thereof, sodium lauryl sulfate, ammonium lauryl sulfate, lauryl sulfate amines, alkyl-substituted aromatic sulfonates, alkyl phosphates, aliphatic or aromatic sulfonic acid formalin condensates, etc. Surfactants, amphoteric surfactants such as lauryl amide propyl betaine and lauryl amino acetate betaine, and nonionic surfactants such as polyethylene glycol fatty acid esters and polyoxyethylene alkylamine , Perfluoroalkyl sulfonate, perfluoroalkyl carboxylate, perfluoroalkyl ethylene oxide adduct, perfluoroalkyl trimethyl ammonium salt, perfluoroalkyl / hydrophilic group-containing oligomer, perfluoroalkyl / lipophilic group-containing oligomer Fluorinated surfactants such as fluoroalkyl group-containing urethanes and the like are included. The amount of the surfactant to be added depends on the type of the surfactant, the solvent, and the supporting substrate to be coated.
The range is 0 ppm to 10%, preferably 50 ppm to 5%, and more preferably 0.01% to 1%.

The film material solution prepared as described above is applied on an alignment film or a substrate which has been subjected to an alignment process such as a rubbing process.

As a coating method, for example, a roll coating method, a die coating method, a bar coating method, a gravure roll coating method, a spray coating method, a dip coating method, a spin coating method and the like can be adopted.

After the application, the solvent is removed by drying, and a heat treatment is performed at a predetermined temperature and for a predetermined time to exhibit a cholesteric liquid crystal phase, thereby completing cholesteric alignment. Next, the cholesteric alignment film formed in the liquid crystal state is rapidly cooled to a temperature equal to or lower than the glass transition point of the polymer liquid crystal, whereby a cholesteric alignment film in which the cholesteric alignment is fixed can be obtained.

Although the thickness of the cholesteric alignment film that can be used in the present invention is not particularly limited, it is usually 0.3 to 20 from the viewpoint of mass productivity and the production process.
μm, preferably 0.5 to 10 μm, and more preferably 0.7 to 3 μm. By transferring the diffraction pattern of the diffraction element substrate to the cholesteric alignment film obtained as described above under specific conditions, the polarization diffraction film of the present invention can be obtained.

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, any diffraction element that generates 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.

When transferring the diffraction pattern to the cholesteric alignment film, the heating and pressurizing conditions are usually from 40 to 3
00 ° C, preferably 70 to 180 ° C, pressure 0.05 to 8
The reaction is performed under the conditions of 0 MPa, preferably 0.1 to 20 MPa. When the temperature is lower than 40 ° C., the transfer of the diffraction pattern may be insufficient in a cholesteric liquid crystal layer having a sufficiently stable alignment state at room temperature. If the temperature exceeds 300 ° C., the cholesteric liquid crystal layer may be decomposed or deteriorated. If the pressure is lower than 0.05 MPa, the transfer of the diffraction pattern may be insufficient. Further 80
If the pressure is higher than MPa, the cholesteric liquid crystal layer and other substrates may be broken.

Although the time required for the transfer differs depending on various characteristics of the polymer liquid crystal forming the cholesteric alignment film, the film form, the material of the diffraction pattern type, etc., it cannot be said unconditionally. , Preferably 0.05 seconds to 1 minute. If the transfer time is shorter than 0.01 second, the transfer of the diffraction pattern may be insufficient. A transfer time exceeding 1 minute is not desirable from the viewpoint of productivity.

As a specific transfer method, for example, using a general compression molding machine, a rolling mill, a calendar roller, a heat roller, a laminator, a hot stamp, an electric heating plate, a thermal head, or the like, which satisfies the above conditions, the cholesteric alignment film is used. By applying the liquid crystal surface of the diffraction element substrate to a molding machine or the like in a state where the diffraction pattern surface of the diffraction element substrate is in contact with the diffraction element substrate, the diffraction pattern of the diffraction element substrate can be transferred to the cholesteric alignment film.

In the polarized light diffractive film obtained by the production method of the present invention, a region exhibiting diffractive ability can be usually formed in a part of the film by transferring a diffraction pattern to a cholesteric alignment film. Here, the region exhibiting the diffractive power means a region which produces an effect such that the light transmitted through the region or the light reflected by the region wraps around a portion which is geometrically shadow. The presence or absence of a region having a diffractive ability is confirmed by, for example, the presence or absence of light (higher-order light) emitted at a certain angle other than light (0th-order light) that enters a laser beam or the like into the aforementioned region and transmits or reflects linearly. can do. Alternatively, by observing the surface shape or cross-sectional shape of the liquid crystal layer with an atomic force microscope, a transmission electron microscope, or the like, it can be confirmed whether or not a region having a diffractive ability is formed. The region exhibiting the diffractive power may be any region on the film surface and / or inside the film. For example, the region is formed on a part of the film surface (film surface region) or a part of the film inside (film internal region). be able to. In addition, the region may be formed 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 internal regions. 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.

The region exhibiting diffractive power formed on a part of the polarization diffraction film is not necessarily formed, for example, as a layer having a uniform thickness on the surface or inside of the film. It is sufficient that a region exhibiting diffractive power is formed in at least a part of the inside of the film.
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.

When the region exhibiting the diffractive power is formed in a layer state, the thickness of the layer (region) exhibiting the diffractive power is usually 50% or less with respect to the thickness of the polarizing diffraction 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. .

Further, the orientation state of the region exhibiting the diffractive ability in the polarizing diffraction film obtained by the production method of the present invention is such that the helical axis direction is not uniformly parallel to the film thickness direction, and preferably the helical axis direction is the film. It is desirable to form a cholesteric orientation that is not uniformly parallel to the thickness direction and the helical pitch is not evenly 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.

Further, in the polarized light diffraction film obtained by the production method of the present invention, when a region exhibiting a diffractive power is present on one of the film surface regions, the front and back of the film, that is, the film surface having the region exhibiting the diffractive power and its surface This shows an optical effect, a color effect and the like slightly different from the film surface opposite to the above. Therefore, it is desirable to select an arrangement position and the like of the film surface of the cholesteric liquid crystal film of the present invention according to the use and the intended function.

The polarization diffraction film to which the diffraction pattern has been transferred can be transferred from the support substrate used for forming the cholesteric alignment film to another substrate, if necessary. Examples of the transfer method include a method in which an adhesive or the like is applied to the polarization diffraction film, another substrate is laminated, the adhesive is cured, and the support substrate is separated from the polarization diffraction film. By appropriately employing this transfer method, it is possible to obtain a form suitable for various uses, for example, an optical laminate in which various support substrates, an adhesive layer, and a polarization diffraction film are laminated in this order. Depending on the application, the film surface on which the diffraction pattern of the polarization diffraction film is transferred or the opposite film surface can be appropriately selected such as by laminating it on a support substrate via an adhesive layer.

The support substrate used for the transfer 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 naphthalate, Sheets and filters of polycarbonate, polyvinyl alcohol, polyacetal, polyarylate, cellulosic plastics, epoxy resin, phenolic resin, etc. Beam 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 used at the time of transfer is not particularly limited, and various hitherto known adhesives and adhesives, hot melt adhesives, heat, light or electron beam-curable adhesives can be used. An 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.

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, and polyol methacrylate. . 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 reactive adhesive of the light or electron beam curing type is appropriately selected depending on the processing temperature of the adhesive and the like, and cannot be specified unconditionally.
Pa · s, preferably 50 to 1000 mPa · s, more preferably 100 to 500 mPa · s. Viscosity 1
When it is lower than 0 mPa · s, it becomes difficult to obtain a desired thickness. On the other hand, if it is higher than 2000 mPa · 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, or a xenon lamp 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.

When a hot-melt adhesive is used as the adhesive, the adhesive is not particularly limited, but the operating temperature of the hot-melt is 250 ° C. or lower, preferably 60 to 20 ° 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 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 an adhesive is not particularly limited. For example, a rubber-based, acrylic, silicone-, or polyvinyl ether-based pressure-sensitive adhesive can be used. Since the thickness of the adhesive varies depending on the application used and its workability, etc., it cannot be said unconditionally,
Usually, it is 0.5 to 50 μm, preferably 1 to 10 μm.

The method of forming the adhesive is not particularly limited, and examples thereof include a roll coating method, a die coating method, a bar coating method, a curtain coating method, an extrusion coating method, a gravure roll coating method, and a spray coating method. It can be formed on a supporting substrate or the like using a known method such as a spin coating method or a spin coating method.

The polarizing diffraction film obtained by the production method of the present invention may be provided with a protective layer on the film surface in order to improve abrasion resistance and light resistance. Here, the film surface means both the surface on which the diffraction pattern is transferred and the surface on which the pattern is not transferred. As the protective layer, for example, a single hard coat layer may be provided, or a laminate composed of two or more layers, such as providing various polymer films and a hard coat layer via an adhesive layer or the like, may be used. .

As the hard coat layer, a cured product of a heat, light or electron beam curable reactive adhesive described above, a vehicle resin for gravure ink, or the like can be preferably used. Examples of the vehicle resin for gravure ink include nitrocellulose, ethyl cellulose, polyamide resin, vinyl chloride / vinyl acetate copolymer, polyvinyl butyral, chloride rubber, cyclized rubber, chlorinated polyolefin, acrylic resin, polyurethane, polyester, and the like. . 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 appropriately added to the gravure ink vehicle resin in order to improve adhesion and film strength. It can also be blended.

Examples of the polymer film include polyethylene, polypropylene, poly (4-methyl-pentene-1), polystyrene, ionomer, polyvinyl chloride, polymethyl methacrylate, polyethylene terephthalate, polyamide, polysulfone, siloxane resin, and epoxy resin. A film formed of a resin, a cellulose resin, or the like can be used as the protective layer. Further, commercially available ultraviolet cut films, hard coat films and the like can also be used as the protective layer.

The adhesive used when laminating the protective layer on the polarizing diffraction film or when forming the protective layer is not particularly limited, but the heat, light or electron beam curing type reaction described above is not limited. A hydrophilic adhesive can be used.

A hard coat layer constituting a protective layer,
The polymer film and the adhesive are, as long as the effects of the present invention are not impaired, for example, ultraviolet absorbers, dyes, pigments, surfactants, fine silica, zirconia, alumina, etc. As described above, the polarizing diffraction film of the present invention has a unique effect that the diffracted light has a circular polarization property, which is not provided by a conventional optical member. 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. However, the polarizer obtained by the manufacturing method of the present invention has a problem. By using a diffractive film, the light use efficiency is extremely high, and it is theoretically possible to use about 100%. In addition, the polarization diffraction film obtained by the production method 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 polarized light diffractive film of the present invention, for example, diffracted light having right polarization can be completely blocked only when a left circularly polarizing plate is used, and complete blocking can be achieved even with other polarizing plates. It is something that cannot be done. 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 polarizing diffraction film obtained by the production method of the present invention has a very wide range of application as a new diffraction function element, and various optical elements, optoelectronic elements, decorative members, and forgery prevention elements. And so on.

Specific examples of the optical element and the optoelectronic element include a polarizing diffraction film of the present invention,
Or a transparent and isotropic film as a supporting substrate, for example, triacetyl cellulose film such as Fujitac (manufactured by Fuji Photo Film Co., Ltd.), Konikatac (manufactured by Konica Corporation), TPX film (manufactured by Mitsui Chemicals, Inc.), An optical laminate obtained by laminating a polarization diffraction film on an arton film (manufactured by Nippon Synthetic Rubber Co., Ltd.), a ZEONEX film (manufactured by Nippon Zeon Co., Ltd.), an acrylene film (manufactured by Mitsubishi Rayon Co., Ltd.), or the like is formed by TN (twisted). nemati
c)-LCD (Liquid Crystal Dis)
play), STN (Super Twisted N)
electronic) -LCD, ECB (Electrica)
lyControlled Birefringen
ce) -LCD, OMI (Optical Mode)
Interference-LCD, OCB (Opt)
allyly Compensated Birefr
ingence) -LCD, HAN (Hybrid A)
lighted Nematic) -LCD, IPS (I
By providing a liquid crystal display such as an n-plane switching-LCD, various LCDs with improved color compensation and / or improved viewing angle can be obtained.
Further, as described above, a polarizing diffraction film or an optical laminate having the film is 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, and a light. It can be used as a diffusing plate or the like, and furthermore, a linear polarizing plate can be obtained by combining with a quarter wavelength plate. An optical member can be provided.

As the decorative member, various design molding materials can be obtained, including a new design film having both a rainbow coloring effect by diffractive ability and a colorful coloring 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 polarizing diffraction film of the present invention incorporating a diffractive pattern having a design is attached to a glass window or the like, the selective reflection peculiar to the cholesteric liquid crystal accompanied by the diffraction pattern looks different in color from the outside, 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, for example, the polarizing diffraction film of the present invention is integrated with a card substrate such as a car driving license, an identification card, a passport, a credit card, a prepaid card, various cash vouchers, a gift card, and securities, a mount, or the like. It can be provided partially, specifically, pasted, embedded, or woven into paper. Further, the polarizing diffraction film 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 of the cholesteric liquid crystal, a circularly-polarized light selective reflectivity, a viewing angle dependency of color,
It also has the effect of exhibiting beautiful cholesteric colors. Therefore, it can be said that it is extremely difficult to forge a film partially having diffractive power, such as the polarization diffraction film of the present invention. 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 polarization diffraction film of the present invention is very useful as an anti-counterfeit element.

These applications are only examples, and the polarizing diffraction film obtained by the production method of the present invention can be used for various applications in which a single diffraction element or a cholesteric alignment film has been used, or a new optical effect. Since it can be expressed, it can be applied to various uses other than the above.

[0051]

EXAMPLES Examples will be described below, but the present invention is not limited to these examples. Various measurement methods used in the present invention will be described. (GPC measurement method) Tosoh GPC (CP8000, CO
8000, UV8000), TSKG3000HX
L, G2000HXL and G1000HXL were connected, and tetrahydrofuran (THF) was added at 25 ° C.
The measurement was performed with a solvent at a flow rate of 0.7 ml / min. A calibration curve was separately prepared using standard polystyrene under the same conditions, and the weight average molecular weight Mw, number average molecular weight Mn, and molecular weight distribution Mw / Mn in terms of polystyrene were determined. (Measurement of glass transition temperature (Tg)) D manufactured by Du Pont
It was measured by SC990. (Measurement of transition temperature (Ti) from liquid crystal phase to isotropic phase) Polarizing microscope B manufactured by Olympus Corporation equipped with a hot stage
The measurement was performed at X50.

(Example 1) Mw is 3000, Mw / Mn
A film was formed by a spin coating method on a rubbed polyphenylene sulfide film of a liquid crystalline polyester (containing an R-form optically active compound) having a 2.0, logarithmic viscosity of 0.124, Tg of 80 ° C, and Ti of 230 ° C. Then 180 ° C
After heat treatment for 5 minutes, a film having a golden specular reflection was obtained.

When the transmission spectrum of the obtained film was measured with an ultraviolet-visible-near infrared spectrophotometer V-570 manufactured by JASCO Corporation, the center wavelength was about 600 nm and the selective reflection wavelength bandwidth was about 100 nm. It was confirmed that a cholesteric alignment film having a fixed cholesteric alignment exhibiting reflection was obtained.

Next, a ruled line diffraction grating film (900 / m) manufactured by Edmund Scientific Japan
m), so that the diffraction surface and the liquid crystal surface of the cholesteric alignment film face each other, and using a laminator DX-350 manufactured by Tokyo Laminex Co., Ltd., heat-presses at 120 ° C., 0.3 MPa and a roll contact time of 0.5 second. went. 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, 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 a polarization diffraction film was obtained by transferring the diffraction pattern of the diffraction grating film to the cholesteric alignment film.

(Example 2) Mw is 7000, Mw / Mn
A film was formed by spin coating on polyphenylene sulfide rubbed with a liquid crystalline polyester (containing an R-form optically active compound) having a 2.0, logarithmic viscosity of 0.144, Tg of 85 ° C and Ti of 230 ° C. Then, when the film was heat-treated at 200 ° C. for 5 minutes, a film having a golden specular reflection was obtained.

When the transmission spectrum of the film was measured with an ultraviolet-visible-near-infrared spectrophotometer V-570 manufactured by JASCO Corporation, a 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 a film in which the cholesteric orientation shown was fixed was formed.

A laminator manufactured by Tokyo Laminex Co., Ltd. is overlapped so that the diffraction surface of the ruled line diffraction grating film (900 lines / mm) manufactured by Edmund Scientific Japan and the liquid crystal surface of the cholesteric alignment film obtained above face each other. Using DX-350, 120 ° C, 0.3MP
a, Heating and pressurization was performed under the condition of a roll contact time of 0.5 seconds. After cooling to room temperature, the ruled line diffraction grating film was removed.

When the cholesteric alignment film surface on which the diffraction grating film was superimposed was observed, the rainbow color caused by the diffraction pattern and the 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, 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 a polarization diffraction film was obtained by transferring the diffraction pattern of the diffraction grating film to the cholesteric alignment film.

Example 3 Mw is 7000, Mw / Mn
A film was formed by spin coating on polyphenylene sulfide rubbed with a liquid crystalline polyester (containing an R-form optically active compound) having a 2.0, logarithmic viscosity of 0.144, Tg of 85 ° C and Ti of 230 ° C. Then, when the film was heat-treated at 200 ° C. for 5 minutes, a film having a golden specular reflection was obtained.

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 a film in which the cholesteric orientation shown was fixed was formed.

A laminator manufactured by Tokyo Laminex Co., Ltd. was overlapped so that the diffraction surface of the ruled line diffractive element film (900 lines / mm) manufactured by Edmund Scientific Japan and the liquid crystal surface of the cholesteric alignment film obtained above faced each other. Using DX-350, 120 ° C, 0.3MP
a, Heating and pressurization was performed under the condition of a roll contact time of 0.5 seconds. After cooling to room temperature, the ruled line diffraction grating film was removed.

When the cholesteric alignment film surface on which the diffraction grating film was superimposed was observed, the rainbow color caused by the diffraction pattern and the selective reflection characteristic of 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, 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 a polarization diffraction film was obtained by transferring the diffraction pattern of the diffraction grating film to the cholesteric alignment film.

An adhesive composed of a commercially available photocurable acrylic oligomer was applied to the cholesteric liquid crystal surface of the obtained polarizing diffraction film using a bar coater so as to have a thickness of 5 μm. Next, a triacetylcellulose film (support substrate) was bonded to the application surface 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 in the 180 ° direction at the interface between the polyphenylene sulfide film and the cholesteric liquid crystal layer.

By the above steps, triacetyl cellulose (supporting substrate) / laminate having the surface on which the diffraction pattern of the polarization diffraction film was transferred facing the triacetyl cellulose side serving as the supporting substrate via the adhesive layer. A laminate of the adhesive layer / polarization diffraction film was obtained.

(Example 4) Mw is 20000, Mw / M
n2.2, logarithmic viscosity 0.344, Tg 102 ° C, T
A film was formed by spin coating on polyphenylene sulfide which had been rubbed with a liquid crystalline polyester (containing an R-form optically active compound) having an i of 250 ° C. Subsequently, when heat-treated at 220 ° C. for 5 minutes, a film exhibiting a golden specular reflection was obtained.

When the transmission spectrum of the film was measured by 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 a film in which the cholesteric orientation shown was fixed was formed.

A laminator manufactured by Tokyo Laminex Co., Ltd. is overlapped so that the diffraction surface of the ruled line diffraction grating film (900 lines / mm) manufactured by Edmund Scientific Japan and the liquid crystal surface of the cholesteric alignment film obtained above face each other. Using DX-350, 150 ° C, 3MPa,
The heating and pressurization were performed under the condition of a roll contact time of 0.5 seconds. After cooling to room temperature, the ruled line diffraction grating film was removed.

When the cholesteric alignment film surface on which the diffraction grating film was superimposed was observed, the rainbow color caused by the diffraction pattern and the 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, 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 a polarization diffraction film was obtained by transferring the diffraction pattern of the diffraction grating film to the cholesteric alignment film.

An adhesive made of a commercially available photo-curable acrylic oligomer in which an ultraviolet absorber and a hard coat agent are blended using a bar coater on the cholesteric liquid crystal surface of the obtained hypothetical polarization film so as to have a thickness of 5 μm. Was applied. Next, a polyethylene terephthalate film was adhered to the application surface using a desktop laminator, and irradiated with ultraviolet light to cure the adhesive. After curing the adhesive,
The end of the polyphenylene sulfide film used as the alignment substrate was held by hand, and the polyphenylene sulfide film was peeled in the 180 ° direction at the interface between the polyphenylene sulfide film and the cholesteric liquid crystal layer.

Next, a triacetylcellulose film is bonded to the cholesteric liquid crystal layer from which the polyphenylene sulfide film has been peeled off via a UV-curable adhesive by using a desktop laminator, and is irradiated with ultraviolet light to cure the adhesive. The terephthalate film was peeled off at the interface with the adhesive layer containing the ultraviolet absorber and the hard coat agent, and the protective layer (adhesive layer (containing the ultraviolet absorber and hard coat agent)) / polarized diffraction film / adhesive layer / trilayer A laminate comprising an acetylcellulose film was obtained.

(Comparative Example 1) Mw is 950, Mw / Mn
2, logarithmic viscosity 0.06, Tg 60 ° C, Ti 220
° C liquid crystalline polyester (contains R-form optically active compound)
Was formed on a rubbed polyphenylene sulfide by spin coating. Subsequently, when heat-treated at 180 ° C. for 5 minutes, a film exhibiting a golden specular reflection was obtained.

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 a film in which the cholesteric orientation shown was fixed was formed.

The laminator manufactured by Tokyo Laminex Co., Ltd. was overlapped so that the diffraction surface of the ruled line diffraction grating film (900 lines / mm) manufactured by Edmund Scientific Japan and the liquid crystal surface of the cholesteric alignment film obtained above faced each other. Using DX-350, 120 ° C, 0.3MP
a, Heating and pressurization was performed under the condition of a roll contact time of 0.5 seconds. Next, after cooling to room temperature, the ruled line diffraction grating film was removed. In the obtained film, cracks occurred in a part of the film, and the cholesteric orientation was disturbed and uneven alignment occurred. Neither did iridescence caused by the diffraction pattern.

Comparative Example 2 Mw (weight average molecular weight) was about 120,000, Mw / Mn was 4.0, logarithmic viscosity was 2.0, Tg
Is 150 ° C and Ti is 240 ° C.
(Containing an optically active compound) on a rubbed polyphenylene sulfide by spin coating.
After heat treatment at 20 ° C. for 20 minutes, a light yellowish film exhibiting weak selective reflection was obtained.

When the transmission spectrum of the film was measured with an ultraviolet-visible-near-infrared spectrophotometer V-570 manufactured by JASCO Corporation, the center wavelength was not clearly specified at about 550 to 600 nm. Showed a broad weak selective reflection. When observed with a microscope BX50 manufactured by Olympus Corporation, a number of alignment defects were observed in the liquid crystal layer.

Next, a scored diffraction grating film (900 / m) manufactured by Edmund Scientific Japan
m) and the liquid crystal surface of the film obtained above are overlapped with each other, and a laminator D manufactured by Tokyo Laminex Co., Ltd.
Using X-350, heating and pressing were performed under the conditions of 120 ° C., 0.03 MPa, and a roll contact time of 0.5 seconds. Next, after cooling to room temperature, the ruled line diffraction grating film was removed. On the liquid crystal surface from which the diffraction grating film was removed, more alignment defects occurred, and no iridescent color due to the diffraction pattern was exhibited.

(Comparative Example 3) Mw is 95000, Mw / M
n = 6.0, logarithmic viscosity = 1.5, Tg = 145 ° C., Ti
Is formed on a polyphenylene sulfide rubbed with a liquid crystalline polyester (containing an R-form optically active compound) at 240 ° C. by spin coating and then heat-treated at 220 ° C. for 20 minutes. was gotten.

When the transmission spectrum of the film was measured with an ultraviolet-visible-near-infrared spectrophotometer V-570 manufactured by JASCO Corporation, the center wavelength was not clearly specified at about 550 to 600 nm. Showed a broad weak selective reflection. When observed with a microscope BX50 manufactured by Olympus Corporation, a number of alignment defects were observed in the liquid crystal layer.

Next, a ruled line diffraction grating film manufactured by Edmund Scientific Japan (900 / m
m) and the liquid crystal surface of the film obtained above are overlapped with each other, and a laminator D manufactured by Tokyo Laminex Co., Ltd.
Using X-350, heating and pressing were performed under the conditions of 120 ° C., 0.03 MPa, and a roll contact time of 0.5 seconds. Next, after cooling to room temperature, the ruled line diffraction grating film was removed.

The liquid crystal surface from which the diffraction grating film has been removed is
Further, many alignment defects were generated, and no iridescent color due to the diffraction pattern was exhibited.

(Comparative Example 4) Mw is 98,000, Mw / M
n is 3.0, logarithmic viscosity is 1.8, Tg is 205 ° C, Ti
Is formed on a rubbed polyphenylene sulfide by rubbing a liquid crystalline polyester (containing an R-form optically active compound) at 250 ° C. by a spin coating method and then heat-treated at 230 ° C. for 20 minutes to give a pale yellow weak selective reflection film was gotten.

When the transmission spectrum of the film was measured with an ultraviolet-visible-near-infrared spectrophotometer V-570 manufactured by JASCO Corporation, the center wavelength was not clearly specified at about 550 to 600 nm. Showed a broad weak selective reflection.

When observed with a microscope BX50 manufactured by Olympus Corporation, a number of alignment defects were observed in the liquid crystal layer.

Next, a ruled line diffraction grating film manufactured by Edmund Scientific Japan (900 / m)
m) and the liquid crystal surface of the film obtained above are overlapped with each other, and a laminator D manufactured by Tokyo Laminex Co., Ltd.
Using X-350, heating and pressing were performed under the conditions of 120 ° C., 3 MPa, and a roll contact time of 0.5 seconds. Next, after cooling to room temperature, the ruled line diffraction grating film was removed. On the liquid crystal surface from which the diffraction grating film was removed, more alignment defects occurred, and no iridescent color due to the diffraction pattern was exhibited.

Comparative Example 5 Mw (weight average molecular weight) was 1
040, Mw / Mn 2.1, logarithmic viscosity 0.06, T
A film was formed by spin coating on polyphenylene sulfide rubbed with a liquid crystalline polyester (containing an R-form optically active compound) having a g of 15 ° C and a Ti of 36 ° C.
After heat treatment for 5 minutes, a film exhibiting a golden specular reflection was obtained.

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 cholesteric liquid crystal layer shown was formed.

A laminator manufactured by Tokyo Laminex Co., Ltd. was overlapped so that the diffraction surface of the ruled line diffractive element film (900 lines / mm) manufactured by Edmund Scientific Japan and the liquid crystal surface of the cholesteric alignment film obtained above faced each other. Using DX-350, 40 ° C, 0.03MP
a, Heating and pressurization was performed under the condition of a roll contact time of 0.5 seconds. Next, after cooling to room temperature, the ruled-type diffraction element film was removed.

In the obtained film, a part of the cholesteric liquid crystal phase was changed to an isotropic phase, the cholesteric alignment was disturbed, and the alignment was uneven. Neither did iridescence caused by the diffraction pattern.

(Comparative Example 6) Mw (weight average molecular weight) of 1
030, Mw / Mn of 2.2, logarithmic viscosity of 0.046,
A film was formed by spin coating on polyphenylene sulfide rubbed with a liquid crystalline polyester (containing an R-form optically active compound) having a Tg of 20 ° C. and a Ti of 115 ° C.
After heat treatment at 00 ° C. for 5 minutes, a film having a golden specular reflection was obtained.

When the transmission spectrum of the film was measured by 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 a film in which the cholesteric orientation shown was fixed was formed.

The diffraction surface of the ruled line diffractive element film (900 lines / mm) manufactured by Edmund Scientific Japan and the liquid crystal surface of the cholesteric alignment film obtained above were overlapped with each other, and were pressed with a hydraulic press. , 50
The heating and pressurization were performed under the conditions of a temperature of 90 ° C. and a pressurization time of 30 seconds. Next, after cooling to room temperature, the ruled-type diffraction element film was removed.

In the obtained film, a part of the film was cracked, and the cholesteric alignment was disturbed, and the alignment was uneven. Neither did iridescence caused by the diffraction pattern.

(Comparative Example 7) Mw is 98900, Mw / M
n = 4.0, logarithmic viscosity = 2.5, Tg = 148 ° C., Ti
Is formed on a rubbed polyphenylene sulfide by rubbing a liquid crystalline polyester (containing an R-form optically active compound) at 250 ° C. by spin coating, and then heat-treated at 220 ° C. for 20 minutes to give a pale yellow weak selective reflection film was gotten. When the transmission spectrum of this film was measured with an ultraviolet-visible-near-infrared spectrophotometer V-570 manufactured by JASCO Corporation, the center wavelength was not clearly specified at about 550 to 600 nm, and the selective reflection wavelength band was broad. It showed weak selective reflection. When observed with a microscope BX50 manufactured by Olympus Corporation, a number of alignment defects were observed in the liquid crystal layer, and uniform cholesteric alignment was not obtained. Next, a laminator DX-350 manufactured by Tokyo Laminex Co., Ltd. was overlapped so that the diffraction surface of the scored type diffraction grating film (900 lines / mm) manufactured by Edmund Scientific Japan and the liquid crystal surface of the film obtained above faced each other. Used, 12
The heating and pressurization were performed under the conditions of 0 ° C., 3 MPa, and a roll contact time of 0.5 seconds. Next, after cooling to room temperature, the ruled line diffraction grating film was removed.

The liquid crystal surface from which the diffraction grating film has been removed is
Further, many alignment defects were generated, and no iridescent color due to the diffraction pattern was exhibited.

[0100]

The polarizing diffraction film obtained by the manufacturing method of the present invention has unique optical characteristics such as diffracted light having a circularly polarizing property, which are not present in conventional optical films. The range is extremely wide, and 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.

Claims (1)

[Claims] 1. A weight average molecular weight Mw measured by GPC (in terms of polystyrene) of 1,000 to 100,000, a molecular weight distribution (Mw / Mn; Mn is a number average molecular weight) of 5 or less, and a logarithmic viscosity of 0.05 to 2.0. (Phenol / tetrachloroethane (60/40 weight ratio) mixed solvent 0.5g concentration)
/ Dl (temperature 30 ° C)) and a glass transition temperature (Tg) of 2
100 ° C. or less, and the transition temperature from the liquid crystal phase to the isotropic phase (T
a) a cholesteric alignment film formed from a film material containing a polymer liquid crystal as an essential component and having a temperature of 40 to 300 ° C. and a pressure of 0.05 to 80 MPa; A method for producing a polarizing diffraction film, wherein the diffraction pattern is transferred to form a region exhibiting diffractive ability in a part of the cholesteric alignment film.