JP2008183812A - Method for producing liquid crystal film and laminated film for optical element - Google Patents

Abstract

The present invention provides a method for producing a liquid crystal film that can obtain an ultra-thin optical film and solve the problems of heat shock test resistance and delamination during rework, which have been problems in the past.
A liquid crystal material layer formed on an alignment substrate and having a fixed liquid crystal alignment is adhered to a re-peelable substrate via an adhesive, and then the alignment substrate is peeled to re-apply the liquid crystal material layer. After transferring to the peelable substrate, the laminated body composed of the removable substrate / adhesive layer 1 / liquid crystal substance layer / adhesive layer 2 / temporary substrate is obtained by adhering to the temporary substrate via the adhesive 2 1st process, 2nd process which peels a releasable board | substrate from the said laminated body, Then, it is made to peel between liquid crystal material layer / adhesive layer 2, and the liquid crystal film which consists of adhesive layer 1 / liquid crystal material layer is obtained 3rd A method for producing a liquid crystal film, which is obtained through at least each of the steps.
[Selection figure] None

Description

  The present invention relates to a method for producing a liquid crystal film useful for various optical elements and a laminated film for an optical element in which the liquid crystal film and a polarizing plate or a retardation plate are laminated.

In recent years, optical films used in liquid crystal display devices are required to have higher durability in addition to excellent optical performance. In particular, liquid crystal display devices for mobile devices such as mobile phones and in-vehicle devices are required to pass strict environmental tests assuming various use conditions.
Thin films (films) consisting of alignment layers of liquid crystal compounds, especially films made of liquid crystal materials with a fixed nematic structure, twisted nematic structure, or nematic hybrid structure, are used for wave plates for liquid crystal display elements, for color compensation and viewing angle compensation. And has excellent performance as an optical rotatory optical element, etc., and contributes to high performance and light weight of various display elements. As a method for producing these films, a method has been proposed in which a layer made of a liquid crystal substance formed on an alignment substrate is transferred onto a translucent substrate that also serves as a support substrate (see, for example, Patent Documents 1 to 3). .)

  Further, as a measure for enduring the severe durability test required for liquid crystal display elements, and for further reduction in thickness and weight, there is also a method for manufacturing an optical element made of a liquid crystal material that does not use a support substrate film. It has been proposed (for example, see Patent Documents 4 to 6). According to such a manufacturing method, after the layer made of the liquid crystal substance formed on the orientation substrate is transferred to the re-peelable substrate once through an adhesive, the re-peelable substrate is peeled off, An optical element made of a liquid crystal material layer without a supporting substrate film can be manufactured.

Usually, these films are used by being bonded to a polarizing plate or a retardation film. The optical film produced from the alignment layer of the liquid crystal compound is not capable of following the contraction of the polarizing plate in a long-term cycle test such as a high-temperature environment test and a high-temperature and high-humidity environment test. There was a problem that appearance abnormalities such as deformation were likely to occur. As a solution to this problem, a method has been proposed in which two protective layers made of a cured acrylic resin layer having a defined glass transition temperature range are used (see Patent Document 7).
However, in the case of the above configuration using two protective layers made of a cured acrylic resin layer, the occurrence of cracks and orientation caused by the cured acrylic resin layer is fixed in a heat shock test in which a high temperature test and a low temperature test are repeated alternately. Due to the lack of adhesion between the liquid crystal material layer / cured acrylic resin layer, it has a problem that it easily peels off at the interface.

JP-A-4-57017 JP-A-4-177216 JP-A-6-242434 JP-A-8-278491 JP 2004-117422 A JP 2004-138697 A JP 2006-284735 A

  The object of the present invention is to provide an ultra-thin liquid crystal film that does not cause abnormal appearance such as cracks in the liquid crystal alignment layer and has no problem in interlayer adhesion even in severe environmental tests such as heat shock tests. It is.

As a result of intensive studies on the above problems, the present inventors have completed the present invention.
That is, according to the first aspect of the present invention, the liquid crystal material layer formed on the alignment substrate and having the liquid crystal alignment fixed thereon is bonded to the re-peelable substrate via the adhesive 1, and then the alignment substrate is peeled off. After the liquid crystal material layer is transferred to the releasable substrate, it is adhered to the temporary substrate via the adhesive 2 to form a removable substrate / adhesive layer 1 / liquid crystal material layer / adhesive layer 2 / temporary substrate. The first step of obtaining the laminate (I), the second step of peeling the releasable substrate from the laminate (I), and then peeling between the liquid crystal substance layer / adhesive layer 2 allows the adhesive layer 1 / It is related with the manufacturing method of the liquid-crystal film characterized by being obtained through each process of the 3rd process of obtaining the liquid-crystal film which consists of a liquid-crystal substance layer.

  In the second aspect of the present invention, a liquid crystal material layer formed on an alignment substrate and having a fixed liquid crystal alignment is adhered to a temporary substrate via an adhesive 1, and then the alignment substrate is peeled off to form a liquid crystal material layer. After being transferred to the temporary substrate, it is adhered to the releasable substrate via the adhesive 2 to form a laminate (II) comprising the temporary substrate / adhesive layer 1 / liquid crystal material layer / adhesive layer 2 / removable substrate. ), A second step of peeling the releasable substrate from the laminate (II), and then peeling between the adhesive layer 1 / liquid crystal material layer to form a liquid crystal material layer / adhesive layer 2 It is related with the manufacturing method of the liquid-crystal film characterized by obtaining through each process of the 3rd process of obtaining a liquid-crystal film at least.

  According to a third aspect of the present invention, the liquid crystal material layer in which the liquid crystal alignment is fixed is composed of a polymer liquid crystal material that aligns the liquid crystal at a temperature equal to or higher than the liquid crystal transition point and enters a glass state at a temperature equal to or lower than the liquid crystal transition point. The present invention relates to a method for producing a liquid crystal film according to the first or second aspect of the invention.

  According to a fourth aspect of the present invention, in the first or second aspect of the present invention, the liquid crystal material layer in which the liquid crystal alignment is fixed is obtained by photo-crosslinking or heat-crosslinking a liquid crystal-aligned low-molecular liquid crystal material. The present invention relates to a method for producing the liquid crystal film.

  5th of this invention is related with the manufacturing method of the liquid-crystal film as described in 1st or 2nd of this invention characterized by a temporary board | substrate or a releasable board | substrate having optical isotropy.

  A sixth aspect of the present invention relates to the method for producing a liquid crystal film according to the first or second aspect, wherein the adhesive to be bonded to the temporary substrate contains a silicone-based or fluorine-based surface modifier.

  Further, according to a seventh aspect of the present invention, there is provided an optical device in which a liquid crystal film produced by the method according to any one of the first to sixth aspects of the present invention is laminated with a polarizing plate or a retardation plate via an adhesive or an adhesive. The present invention relates to a laminated film for an element.

  In the above description, “/” represents the interface of each layer, and will be expressed similarly in the following.

  According to the present invention, an ultra-thin optical film can be obtained, and the problems of heat shock test resistance and delamination at the time of rework, which have been conventional problems, can be solved.

Hereinafter, the present invention will be described in detail.
The liquid crystal material layer in which the alignment of the liquid crystal used in the present invention is fixed is a layer fixed by using means for fixing the liquid crystal material in the alignment state. As a means of fixing the alignment of the liquid crystal, in the case of a polymer liquid crystal substance, a method of rapidly cooling from the alignment state to fix it in a vitrified state, a low molecular liquid crystal substance having a reactive functional group or a polymer liquid crystal substance is aligned. Then, the functional group is reacted (cured, crosslinked, etc.) and fixed.

  Examples of the reactive functional group include a vinyl group, a (meth) acryloyl group, a vinyloxy group, an epoxy group, an oxetanyl group, a carboxyl group, a hydroxyl group, an amino group, an isocyanate group, and an acid anhydride. The reaction is carried out in a suitable manner.

  The liquid crystal material that can be used for the liquid crystal material layer can be selected from a wide range regardless of whether it is a low-molecular liquid crystal material or a high-molecular liquid crystal material, depending on the intended use and manufacturing method of the liquid crystal film. Substances are preferred. Furthermore, the molecular shape of the liquid crystal substance may be a rod shape or a disk shape. For example, a discotic liquid crystal compound exhibiting a discotic nematic liquid crystal property can also be used.

  Examples of the liquid crystal phase of the liquid crystal material layer before fixing include a nematic phase, a twisted nematic phase, a cholesteric phase, a hybrid nematic phase, a hybrid twisted nematic phase, a discotic nematic phase, and a smectic phase. Examples of the alignment state include homogeneous alignment that is horizontally aligned on the alignment substrate surface and homeotropic alignment that is aligned vertically.

As the polymer liquid crystal material, various main chain polymer liquid crystal materials, side chain polymer liquid crystal materials, or a mixture thereof can be used.
Main chain type polymer liquid crystal substances include polyester, polyamide, polycarbonate, polyimide, polyurethane, polybenzimidazole, polybenzoxazole, polybenzthiazole, polyazomethine, polyesteramide, polyester carbonate Polymer liquid crystal substances such as polyester and polyesterimide, or mixtures thereof.
Further, as the side chain type polymer liquid crystal substance, a substance having a skeleton chain of a linear or cyclic structure such as polyacrylate, polymethacrylate, polyvinyl, polysiloxane, polyether, polymalonate, polyester, etc. In addition, a polymer liquid crystal substance in which a mesogen group is bonded as a side chain, or a mixture thereof.
Among these, a polyester-based main chain type polymer liquid crystal substance is preferable because of ease of synthesis and alignment.

Low molecular liquid crystal substances include saturated benzene carboxylic acids, unsaturated benzene carboxylic acids, biphenyl carboxylic acids, aromatic oxycarboxylic acids, Schiff base types, bisazomethine compounds, azo compounds, azoxy compounds, cyclohexane ester compounds Examples thereof include a compound exhibiting liquid crystallinity in which the reactive functional group is introduced at the terminal, such as sterol compounds, and a composition obtained by adding a crosslinkable compound to a compound exhibiting liquid crystallinity among the compounds.
Examples of the discotic liquid crystal compound include triphenylene and torquesen.

  Furthermore, various compounds having functional groups or sites that can react by heat or photocrosslinking reaction or the like in the liquid crystal substance may be blended within a range that does not hinder the development of liquid crystallinity. Examples of the functional group capable of undergoing a crosslinking reaction include the various reactive functional groups described above.

  The liquid crystal material layer in which the alignment of the liquid crystal is fixed is obtained by applying a composition containing the liquid crystal material and various compounds added as necessary onto an alignment substrate in a molten state, or a solution of the composition. Means for fixing the orientation such as light irradiation and / or heat treatment, if necessary, after drying and heat treatment (orientation of the liquid crystal) the coating film formed on the orientation substrate by the method of coating on the orientation substrate, etc. It is formed by fixing the orientation using

  The solvent used for the preparation of the solution is not particularly limited as long as it can dissolve the liquid crystal substance and the composition used in the present invention and can be distilled off under appropriate conditions. Generally, acetone, methyl ethyl ketone, isophorone, etc. Ketones, butoxyethyl alcohol, hexyloxyethyl alcohol, ether alcohols such as methoxy-2-propanol, glycol ethers such as ethylene glycol dimethyl ether and diethylene glycol dimethyl ether, esters such as ethyl acetate, methoxypropyl acetate, and ethyl lactate, Phenols such as phenol and chlorophenol, amides such as N, N-dimethylformamide, N, N-dimethylacetamide and N-methylpyrrolidone, chloroform, tetrachloroethane, dichlorobenzene What halogenated hydrocarbons such or a mixture of these systems are preferably used. Further, in order to form a uniform coating film on the alignment substrate, a surfactant, an antifoaming agent, a leveling agent and the like may be added to the solution. Furthermore, a dichroic dye, a normal dye, a pigment, or the like can be added within a range that does not hinder the expression of liquid crystallinity for the purpose of coloring.

  The application method is not particularly limited as long as the uniformity of the coating film is ensured, and a known method can be adopted. Examples thereof include a roll coating method, a die coating method, a dip coating method, a curtain coating method, and a spin coating method. After the application, a solvent removal (drying) step by a method such as a heater or hot air blowing may be added. The film thickness of the applied film in a dry state is usually 0.1 μm to 50 μm, preferably 0.2 μm to 20 μm, and more preferably 0.3 μm to 10 μm. Outside this range, it is not preferable because the optical performance of the obtained liquid crystal material layer is insufficient or the alignment of the liquid crystal material is insufficient.

  Subsequently, if necessary, after alignment of the liquid crystal is formed by heat treatment or the like, the alignment is fixed. In the heat treatment, the liquid crystal is aligned by the self-alignment ability inherent in the liquid crystal substance by heating to the liquid crystal phase expression temperature range. As conditions for the heat treatment, optimum conditions and limit values differ depending on the liquid crystal phase behavior temperature (transition temperature) of the liquid crystal substance used, but it cannot be generally stated, but is usually in the range of 10 to 300 ° C, preferably 30 to 250 ° C. . If the temperature is too low, the alignment of the liquid crystal may not proceed sufficiently, and if the temperature is high, the liquid crystal substance may decompose or adversely affect the alignment substrate. Moreover, about heat processing time, it is 3 seconds-60 minutes normally, Preferably it is the range of 10 seconds-30 minutes. When the heat treatment time is shorter than 3 seconds, the alignment of the liquid crystal may not be sufficiently completed, and when the heat treatment time exceeds 60 minutes, the productivity is extremely deteriorated. After the alignment of the liquid crystal material is completed by heat treatment or the like, the liquid crystal material layer on the alignment substrate is fixed as it is using means suitable for the liquid crystal material used.

  Examples of the alignment substrate include polyimide, polyamide, polyamideimide, polyphenylene sulfide, polyphenylene oxide, polyether ketone, polyether ether ketone, polyether sulfone, polysulfone, polyethylene terephthalate, polyethylene naphthalate, polyarylate, triacetyl cellulose, epoxy Examples of the film include a resin and a phenol resin.

Some of these films exhibit a sufficient alignment ability for the liquid crystal substance used in the present invention without performing a treatment for expressing the alignment ability again depending on the production method, but the alignment ability is insufficient, or When the orientation ability is not exhibited, these films are stretched under moderate heating, the film surface is rubbed in one direction with a rayon cloth or the like, so-called rubbing treatment is performed, polyimide, polyvinyl alcohol, silane cup on the film A film that exhibits orientation ability by providing an orientation film made of a known orientation agent such as a ring agent and performing rubbing treatment, oblique vapor deposition treatment such as silicon oxide, or a combination thereof may be used.
Further, as the alignment substrate, a metal plate such as aluminum, iron, or copper having various regular fine grooves on the surface, various glass plates, or the like can be used.

  Here, the alignment treatment direction of the alignment substrate is not particularly limited, and can be appropriately selected by performing each of the above treatments in an arbitrary direction. In particular, when a liquid crystal film formed on a long alignment substrate is handled, a predetermined angle is selected with respect to the length direction (MD) of the long continuous film, and an oblique direction is applied as necessary. It is desirable to perform an orientation treatment. By laminating the liquid crystal film in an axial arrangement that can exhibit optimum optical characteristics by performing an orientation treatment in a predetermined angular direction, bonding in a state in which MDs of long films are aligned (so-called roll-to-roll bonding) This is extremely advantageous from the standpoints that it is possible to increase the efficiency of product collection.

  Next, a method for transferring the liquid crystal material layer formed on the alignment substrate onto the removable substrate or the temporary substrate will be described.

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

In particular, 4-methylpentene-1 resin, polymethyl methacrylate, polystyrene, polycarbonate, polyethersulfone, polyarylate, amorphous polyolefin, norbornene, which are transparent and optically isotropic films with excellent optical defect inspection properties A plastic film such as an epoxy resin, triacetyl cellulose, or epoxy resin is preferably used.
In addition, even if the releasable substrate and the temporary substrate are made of the same material, they can be appropriately used according to the purpose by the production method, various treatments, and selection of the adhesive used in the present invention.

  Further, the thickness of these substrates is preferably 10 to 100 μm, and particularly preferably 25 to 50 μm. If the thickness is too thick, the peeling point may not be stable and the peelability may be deteriorated. On the other hand, if the thickness is too thin, the mechanical strength of the film cannot be maintained, and troubles such as tearing during production may occur.

  When the above-mentioned film is used as the removable substrate, the surface can be coated with silicone or fluorine in advance, or an organic thin film or an inorganic thin film can be formed in order to give appropriate removability. I can keep it. For the same purpose, the surface of the plastic film can be subjected to chemical treatment such as saponification treatment or physical treatment such as corona discharge treatment or UV-ozone treatment.

Moreover, in order to adjust the peelability of a releasable board | substrate, a lubricant and a surface modifier can also be contained in said film. The lubricant is not particularly limited in type and amount as long as it does not adversely affect optical defect inspection and peelability. Specific examples of the lubricant include fine silica, fine alumina, and the like, and as an indicator of the amount added, the haze value of the removable substrate is usually 50% or less, preferably 30% or less. If the addition amount is too small, the effect of addition is not recognized. On the other hand, if the addition amount is too large, the optical defect inspection property deteriorates, which is not preferable.
Moreover, you may contain other well-known various additives, for example, an antiblocking agent, antioxidant, an antistatic agent, a heat stabilizer, an impact modifier etc. as needed.

In the present invention, a release layer is formed between the liquid crystal substance layer and another layer by using a releasable substrate in which a release layer that can be peeled from the substrate is previously formed on the surface of the releasable substrate. It is also possible to form. By forming the release layer, it is possible to obtain a stress shielding effect for suppressing the appearance change (for example, wave out) of the thin film liquid crystal material layer at the time of manufacturing or environmental testing. Here, the release layer is not particularly limited, but an optically isotropic transparent layer is preferable, and examples thereof include polymers such as acrylic, methacrylic, nitrocellulose, and epoxy compounds, and mixtures thereof. be able to. The film thickness of the release layer is 0.3 μm or more and 40 μm or less, preferably 0.5 μm or more and 10 μm or less, and the glass transition point (Tg) is 20 ° C. or more, preferably 50 ° C. or more. The material is not particularly limited as long as it is a transparent layer and does not significantly impair the optical properties of the liquid crystal material layer. If the film thickness and the glass transition point are outside this range, the effect is insufficient, or the product becomes too thick.
The release layer may be controlled in physical properties by partial crosslinking by adding a crosslinking component, addition of a plasticizer, addition of a lubricant, or the like.

  Further, the method for forming the release layer is not particularly limited. For example, a material that becomes the release layer having the above-described film thickness is applied on a removable substrate film such as polyethylene, polypropylene, and polyethylene terephthalate. For example, a transfer method may be used in which the layer is formed by a method such as extrusion, and this layer is closely attached via an adhesive / adhesive layer or a transparent protective layer, and then the removable substrate film is peeled off.

  On the other hand, when the above-described film is used as a temporary substrate, it is necessary to perform the peeling step in a form bonded to the adhesive layer, so that appropriate adhesiveness with the adhesive layer is required. For the purpose of increasing the adhesive strength, an organic thin film or an inorganic thin film may be formed on the surface in advance, or corona discharge treatment or UV-ozone treatment may be performed.

  In order to transfer the liquid crystal material layer formed on the alignment substrate onto the removable substrate as described above or on the temporary substrate, the photocurable acrylic resin adhesive is applied to the liquid crystal material layer, and then the removability is achieved. A substrate or a temporary substrate is bonded, and light is irradiated to the substrate from the outside so as to be photocured and bonded, and then the alignment substrate is peeled off, whereby transfer can be easily performed. The cured acrylic resin layer as an adhesive is formed by applying a curable acrylic oligomer or monomer and curing it.

  As the curable acrylate used, for example, a known photocurable acrylic adhesive can be used, for example, various acrylic oligomers or monomers such as polyester acrylate, epoxy acrylate, urethane acrylate, polyether acrylate, silicone acrylate, etc. Or a mixture thereof or a mixture of these with various reactive diluents.

In addition, various fine particles and a surface modifier can be added to these adhesives as long as the properties are not impaired.
Examples of the fine particles include fine particles having a refractive index different from that of the compound constituting the adhesive, conductive fine particles for improving antistatic performance without impairing transparency, and fine particles for improving wear resistance. Specifically, fine silica, fine alumina, ITO (Indium Tin Oxide) fine particles, silver fine particles, various synthetic resin fine particles and the like can be mentioned.
The surface modifier is not particularly limited as long as it has good compatibility with the adhesive and does not affect the curability of the adhesive or the optical performance after curing, and is an ionic or nonionic water-soluble interface. Activators, oil-soluble surfactants, polymer surfactants, fluorosurfactants, silicone surfactants, organometallic surfactants, reactive surfactants, and the like can be used.

  In the present invention, different types of adhesives on the releasable substrate side and adhesives on the temporary substrate side can be used as necessary. In particular, the adhesive used on the releasable substrate side has a low adhesive strength that can be easily peeled off from the releasable substrate and has sufficient adhesive strength with the liquid crystal material layer, while the temporary substrate side. It is desirable that the adhesive used in the above has a low adhesive strength that can be easily peeled off from the liquid crystal material layer and has a sufficient adhesive strength with respect to the temporary substrate.

  Regarding the peel strength between the releasable substrate / adhesive layer, even if it is a releasable substrate manufactured from the same material, it changes depending on the manufacturing method, surface condition, wettability with the adhesive used, etc. However, the peel force at the interface with the adhesive (180 ° peel, peel rate 30 cm / min, measured at room temperature) is usually 0.3 to 12 N / m, preferably 0.5 to 8.0 N / m m is desirable. When the peel force is lower than this value, the peel force is too low when the alignment substrate is peeled off after the liquid crystal material layer on the alignment substrate is bonded to the re-peelable substrate, and the releasable substrate may be lifted. If the desired peeled state at the desired interface cannot be obtained, the transfer of the liquid crystal material layer to the removable substrate becomes insufficient, and the releasable substrate is peeled off when the peeling force is too high. At this time, it is not preferable because the liquid crystal material layer is broken or cannot be peeled off at the interface with a desired layer.

  As the adhesive force between the adhesive layer used on the removable substrate side and the liquid crystal substance layer, the peel force at the interface (180 ° peel, peel rate 30 cm / min, measured at room temperature) is usually 3. It is 9 N / m or more, preferably 5.8 N / m or more. If the peel force is lower than this value, there is a risk of peeling at the interface during handling during processing or during re-peeling (rework) after laminating a liquid crystal cell in a product after laminating a polarizing plate or an adhesive layer. There is not preferable.

  On the other hand, the adhesive force between the temporary substrate and the adhesive layer is generally determined because it changes depending on the manufacturing method, surface condition, wettability with the used adhesive, etc. even if the temporary substrate is manufactured from the same material. However, the peeling force at the interface (180 ° peeling, peeling rate 30 cm / min, measured at room temperature) is usually 2.0 N / m or more, preferably 3.7 N / m or more. When the adhesive force is lower than this value, when the temporary substrate and the adhesive layer are peeled from the liquid crystal material layer, floating or peeling occurs between the temporary substrate and the adhesive layer, and a desired interface (adhesive layer / It is not preferable because a good peeling state between the liquid crystal substance layers) may not be obtained.

  Further, as the adhesive force between the adhesive layer used on the temporary substrate side and the liquid crystal material layer, the peeling force at the interface (180 ° peeling, peeling rate 30 cm / min, measured at room temperature) is usually 0. It is desired to be 3 to 3.1 N / m, preferably 0.9 to 1.9 N / m. When the peeling force is lower than this value, there is a possibility that floating or peeling may occur between the adhesive layer / liquid crystal substance layer during the process of peeling the releasable substrate. Further, when the peeling force is too high, it is not preferable because, when the temporary substrate is peeled off, the liquid crystal material layer is broken or the peeling cannot be performed at the interface with the desired layer.

  In particular, if a surface modifier is added to the adhesive used on the temporary substrate side as required, smooth peeling can be performed at the interface with the liquid crystal material layer. The surface modifier is not particularly limited as long as it has good compatibility with the adhesive and does not affect the curability of the adhesive or the optical performance after curing, an ionic or nonionic water-soluble surfactant, Oil-soluble surfactants, polymer surfactants, fluorine-based surfactants, silicone-based surfactants, organometallic surfactants, reactive surfactants, and the like can be used. Of these, fluorine-based surfactants and silicone-based surfactants are preferable because they have a great effect of reducing the peeling force.

  When the surface modifier is added, the addition amount is 0.01 parts by weight to 15 parts by weight, preferably 0.05 parts by weight to 12 parts by weight when the amount of the adhesive before addition is 100 parts by weight. More desirably, the amount is 0.1 to 10 parts by weight. If the addition amount is too small, the effect of addition may be hardly recognized. If the addition amount is too large, foaming of the adhesive may be severe and air bubbles may be mixed into the cured product.

Next, a method for curing these curable acrylic adhesives will be described.
The curing method is not particularly limited, and examples thereof include heat curing, redox system room temperature curing, anaerobic curing, active ray curing such as ultraviolet rays and electron beams. A preferable curing method is a curing method using active rays such as ultraviolet rays and electron beams. This curing method is preferable because it generates little or no heat and thus has little influence on the liquid crystal substance layer in which the alignment is fixed. The reaction can be performed by adding various known photoinitiators and irradiating light from a light source such as a metal halide lamp, a high-pressure mercury lamp, a low-pressure mercury lamp, a xenon lamp, an arc lamp, a laser, or a synchrotron radiation light source. The amount of irradiation per unit area (one square centimeter) is usually in the range of 1 to 2000 mJ, preferably 10 to 1000 mJ as the integrated irradiation amount. However, this is not the case when the absorption region of the photoinitiator and the spectrum of the light source are significantly different, or when the reactive compound itself has the ability to absorb the light source wavelength. In these cases, an appropriate photosensitizer or a method of using a mixture of two or more photoinitiators having different absorption wavelengths can be used. The acceleration voltage in the case of the electron beam curable type is usually 10 kV to 200 kV, preferably 50 kV to 100 kV.

  Examples of the photocuring initiator in the case of curing by actinic radiation include, for example, benzoin ether, benzoin ethyl ether, benzyl methyl ketal, hydroxyphenyl ketone, 1,1-dichloroacetophenone, thioxanthones, or benzophenones in combination with amines. Etc. are exemplified. The amount used is in the range of 0.1 to 10% by weight of the resin.

In the method of the present invention, a liquid crystal material layer formed on an alignment substrate is bonded to a removable substrate or a temporary substrate via an adhesive to obtain the following laminate.
Laminate (I): Removable substrate / Adhesive layer 1 / Liquid crystal layer / Adhesive layer 2 / Temporary substrate Laminate (II): Temporary substrate / Adhesive layer 1 / Liquid crystal layer / Adhesive layer 2 / Removable substrate By peeling the removable substrate and the adhesive layer / temporary substrate from the laminate, the following thin liquid crystal film can be obtained.
Adhesive Layer 1 / Liquid Crystal Material Layer Liquid Crystal Material Layer / Adhesive Layer 2

  Here, the adhesive layer used in the present invention has a glass transition temperature (Tg) after curing of 20 ° C. or higher and 250 ° C. or lower, desirably 30 ° C. or higher and 200 ° C. or lower. When the Tg of the adhesive layer is lower than 20 ° C., in the environmental test such as high temperature and high humidity, the cycle environmental test between high temperature and high humidity, the heat shock test between high temperature and low temperature, etc. The liquid crystal material layer is likely to cause an appearance abnormality (cracking, deformation, etc.). On the other hand, when the glass transition temperature is higher than 250 ° C., there arises a problem that the adhesive layer is easily cracked during processing or environmental testing.

  In addition, the thickness of each adhesive layer is 0.1 to 50 μm, desirably 0.5 to 20 μm, and more desirably 1 to 10 μm. If the thickness is too thin, the protective effect of the liquid crystal material layer in the environmental test is insufficient, and if it is too thick, it takes time to cure the acrylic resin layer and the product thickness is also unfavorable.

The liquid crystal film of the present invention obtained as described above is usually used as a color compensator for a liquid crystal display element, a viewing angle compensator or the like. A polymer stretched film, an adhesive layer for attaching to a liquid crystal cell, and the like are also laminated. Here, lamination | stacking, such as a polarizing plate, a liquid crystal aligning film, a polymer stretched film, can be laminated | stacked via a well-known translucent adhesive or adhesive agent. As a laminate obtained in this way, for example,
(1) Polarizing plate / viscous / adhesive layer / liquid crystal film / viscous / adhesive layer / separator (2) Polarizing plate / viscous / adhesive layer / retardation plate (polymer stretched film) / viscous / adhesive layer / Liquid crystal film / viscous / adhesive layer / separator (3) Polarizing plate / viscous / adhesive layer / liquid crystal film / viscous / adhesive layer / liquid crystal film / viscous / adhesive layer / separator May be the same or different)
(4) Polarizing plate / viscous / adhesive layer / liquid crystal film / viscous / adhesive layer / retardation plate (polymer stretched film) / viscous / adhesive layer / separator and the like.
Here, a plurality of liquid crystal films, liquid crystal alignment films, polymer stretch films and the like can be laminated.

  The polarizing plate is not particularly limited, and a polarizing plate that is usually used in a liquid crystal display device can be used as appropriate, but a thin film type that has been recently developed and marketed is desirable. Specifically, iodine and / or dichroism is applied to a hydrophilic polymer film made of a PVA polarizing film such as polyvinyl alcohol (PVA) or partially acetalized PVA, or a partially saponified ethylene-vinyl acetate copolymer. A polarizing film formed by adsorbing a dye and stretching, a polarizing film composed of a polyene oriented film such as a dehydrated PVA product or a dehydrochlorinated polyvinyl chloride product, and the like can be used. A reflective polarizing film can also be used.

  The polarizing plate may be used alone, or may be provided with a transparent protective layer or the like on one side or both sides of the polarizing film for the purpose of improving strength, improving moisture resistance, improving heat resistance, etc. good. Examples of the transparent protective layer include those obtained by laminating transparent plastic films such as polyester and triacetyl cellulose directly or via an adhesive layer, resin coating layers, acrylic and epoxy photocurable resin layers, and the like. It is done. When these transparent protective layers are coated on both sides of the polarizing film, the same transparent protective layer may be provided on both sides, or different transparent protective layers may be provided.

  The polymer stretched film may be uniaxial or biaxial composed of cellulose, polycarbonate, polyarylate, polysulfone, polyvinyl alcohol (PVA), polyacryl, polyether sulfone, cyclic polyolefin, etc. A stretched retardation film can be exemplified. Among them, a uniaxially stretched film of a cyclic polyolefin type such as polycarbonate or norbornene is preferable from the viewpoint of ease of production, film uniformity, or optical characteristics.

  Here, the direction of stretching is not particularly limited, and can be appropriately selected by performing in any direction. In particular, when handling a long polymer stretched film, it is stretched in an oblique direction (obliquely stretched) or a width direction (TD) as required at a predetermined angle with respect to the MD of the long continuous film ( It is desirable to be subjected to (lateral stretching) treatment. When a stretched film is laminated in an axial arrangement that can exhibit optimal optical characteristics with a liquid crystal film or polarizing plate by stretching in a direction of a predetermined angle, it is applied in a state where MDs of long films are aligned. This is extremely advantageous from the standpoints that bonding (so-called roll-to-roll bonding) is possible, or the efficiency of product collection is increased.

Next, a method for producing a laminated film for optical elements in which the liquid crystal film of the present invention is bonded to a polarizing plate will be described.
First, the laminate (I) or (II) as exemplified below is obtained by the procedure described above.
Laminate (I): Removable substrate / Adhesive layer 1 / Liquid crystal layer / Adhesive layer 2 / Temporary substrate Laminate (II): Temporary substrate / Adhesive layer 1 / Liquid crystal layer / Adhesive layer 2 / Removable substrate

  The subsequent procedure is not particularly limited depending on the intended use or the partner to be laminated, but the releasable substrate or temporary substrate is peeled off from the laminate (I) or (II), and the polarizing plate, A method of peeling the remaining temporary substrate together with the adhesive layer after bonding with a molecular stretched film, a liquid crystal alignment film, a separator and the like is exemplified. Here, it is desirable that at least one of the removable substrate and the temporary substrate is optically isotropic in order to inspect defects and unevenness under polarized light.

For example, the post-process will be described in the case where the removable substrate is optically anisotropic and the temporary substrate is optically isotropic.
First, by removing the removable substrate first, it is possible to inspect under polarized light with the temporary substrate attached. Next, after sticking to this with a polarizing plate, a polymer stretched film, another liquid crystal alignment film, a separator, etc. via an adhesive / adhesive agent, the temporary substrate is peeled off together with the adhesive layer, thereby the liquid crystal film of the present invention. Can be laminated. Other members (polarizing plate, polymer stretched film, other liquid crystal alignment film, separator, etc.) are sequentially laminated using an adhesive / adhesive according to the application and necessity.

  The stacking order is selected in consideration of production efficiency, member removal efficiency, and the like. For example, in order to maximize the optical performance of the liquid crystal film and polarizing plate or retardation plate used, it is not possible to perform bonding (so-called roll-to-roll bonding) in a state where the MD of the long film is aligned. In the case of performing roll-to-sheet bonding or sheet-to-sheet bonding, which is performed after cutting at least one of the sheets into a sheet shape, a releasable substrate (from the above-mentioned laminate (I) or (II) ( Alternatively, after removing the temporary substrate) and pasting the separator with the separator with a sticky adhesive, first roll-to-roll, and then sequentially laminating other members (polarizing plate, polymer stretched film, other liquid crystal alignment film, etc.) Is.

The laminated film for an optical element in which the liquid crystal film of the present invention is bonded to a polarizing plate or a retardation plate functions as a compensation member for various liquid crystal display devices, an elliptically polarizing plate, and a circularly polarizing plate according to the optical parameters of the liquid crystal material layer. can do.
That is, since the liquid crystal material layer constituting the laminated film for optical elements is, for example, a liquid crystal material layer in which nematic alignment or twisted nematic alignment is fixed functions as a retardation plate, the liquid crystal material layer is used as a constituent member of the present invention. The laminated film for optical elements can be used as a compensation plate for transmission or reflection type liquid crystal display devices of STN type, TN type, OCB type, HAN type and the like.
In addition, the liquid crystal material layer in which the nematic hybrid alignment is fixed can be used as a retardation film or a wave plate using retardation when viewed from the front, and the direction of the retardation value (film thickness direction) Taking advantage of the asymmetry due to the inclination of the molecular axis of the TN liquid crystal display device, it can also be used as a viewing angle improving member of a TN type liquid crystal display device.

  In addition, the liquid crystal material layer having a 1/4 wavelength plate function can be used as a circularly polarizing plate, a reflection type liquid crystal display device, an antireflection filter of an EL display device, or the like by combining with a polarizing plate as in the present invention. In particular, in order to obtain a broadband quarter-wave plate that functions over a wide band in the visible light region, a quarter-wave plate having a phase difference of birefringent light in a monochromatic light of 550 nm and a wavelength of 550 nm is approximately ¼ wavelength. It is generally known that it is effective to laminate a half-wave plate whose phase difference of birefringent light in monochromatic light is approximately ½ wavelength with their slow axes intersecting. In fact, it is widely used in reflective liquid crystal display devices and the like.

  That is, if a technique for obtaining a thin laminated film for an optical element as in the present invention is used, a thin broadband quarter-wave plate, which was difficult with a conventional polymer stretched film alone, can be obtained. Here, the retardation value of the quarter-wave plate is usually in the range of 70 nm to 180 nm, preferably 90 nm to 160 nm, and particularly preferably 120 nm to 150 nm. Moreover, the retardation value of a half-wave plate is 180 nm-320 nm normally, Preferably it is 200 nm-300 nm, Most preferably, it is the range of 220 nm-280 nm. If the retardation range of the quarter-wave plate and the half-wave plate deviates from the above, unnecessary coloring may occur in the liquid crystal display device. The retardation value represents the product of birefringence Δn and film thickness d.

  Furthermore, in the laminated film for an optical element of the present invention, if the liquid crystal material layer constituting the laminated body has a fixed cholesteric orientation or smectic orientation, a polarized reflection film for improving brightness, a reflective color filter, It can be used for various anti-counterfeiting elements, decorative films, etc. that take advantage of the color change of reflected light depending on the viewing angle due to selective reflectivity.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited thereto. The retardation (product of birefringence Δn and film thickness d) in this example is a value at a wavelength of 550 nm unless otherwise specified.

[Preparation Example]
Polycondensation was performed at 270 ° C. for 12 hours in a nitrogen atmosphere using 50 mmol of terephthalic acid, 50 mmol of 2,6-naphthalenedicarboxylic acid, 40 mmol of methylhydroquinone diacetate, 60 mmol of catechol diacetate and 60 mg of N-methylimidazole. Next, the obtained reaction product was dissolved in tetrachloroethane, and then purified by reprecipitation with methanol to obtain 14.6 g of a liquid crystalline polyester. The logarithmic viscosity of this liquid crystalline polyester (Polymer 1) (phenol / tetrachloroethane (6/4 mass ratio) mixed solvent: 30 ° C.) is 0.16 dl / g, has a nematic phase as a liquid crystal phase, isotropic phase-liquid crystal phase The transition temperature was 250 ° C. or higher, and the glass transition temperature measured by a differential scanning calorimeter (DSC) was 112 ° C.
A solution was prepared by dissolving 20 g of Polymer 1 in 80 g of N-methyl-2-pyrrolidone. This solution is applied onto a polyimide film (trade name “Kapton”, manufactured by DuPont) rubbed with a rayon cloth, and the solvent is dried and removed, followed by heat treatment at 210 ° C. for 20 minutes for nematic orientation. A structure was formed. After the heat treatment, the nematic alignment structure was fixed by cooling to room temperature to obtain a liquid crystal material layer uniformly aligned with an actual film thickness of 0.7 μm on the polyimide film (liquid crystal material layer 1). The actual film thickness was measured using a stylus type film thickness meter.

[Example 1]
5 μm of UV-curable acrylic adhesive 1 (manufactured by Toagosei Co., Ltd.) having a glass transition temperature (Tg) of 47 ° C. on the liquid crystal material layer 1 obtained in the preparation example (surface opposite to the polyimide film) A 50 μm thick polyethylene terephthalate (PET) film (manufactured by Toray Industries, Inc.) is laminated thereon, and the acrylic resin layer 1 is cured by UV irradiation of about 600 mJ. I let you. Thereafter, the liquid crystal material layer is transferred onto the PET film by peeling the polyimide film from the laminate in which the PET film / cured acrylic resin layer 1 / liquid crystal material layer 1 / polyimide film is integrated, and the PET film / cured A laminate composed of acrylic resin layer 1 / liquid crystal material layer 1 was obtained.

  Furthermore, a UV curable acrylic adhesive 2 (manufactured by Toagosei Co., Ltd.) having a Tg = 135 ° C. was applied as a 5 μm thick acrylic resin layer 2 on the liquid crystal material layer 1 of the laminate. A 40 μm thick triacetyl cellulose (TAC) film (manufactured by Fuji Film Co., Ltd.) is laminated thereon, and the acrylic resin layer 2 is cured by UV irradiation of about 600 mJ to obtain a PET film / cured acrylic resin layer 1 / Laminated body (A) comprising liquid crystal material layer 1 / cured acrylic resin layer 2 / TAC film was obtained. Here, Δnd of the laminate after peeling the PET film and the TAC film was 128 nm.

  Next, after peeling off the PET film of the laminate (A), a film in which a pressure-sensitive adhesive layer having a thickness of 25 μm was previously formed on the surface of the cured acrylic resin layer 1 was bonded to the separator / A laminate (B) composed of pressure-sensitive adhesive layer / cured acrylic resin layer 1 / liquid crystal substance layer 1 / cured acrylic resin layer 2 / TAC film was obtained.

  Next, after peeling the TAC film side from the laminate (B) at the liquid crystal material layer 1 / cured acrylic resin layer 2 interface, a 40 μm thick ZEONOR film (Zeon Co., Ltd., Δnd is 275 nm) and a polarizing plate (manufactured by Sumitomo Chemical Co., Ltd.) via a 20 μm thick adhesive, thereby polarizing plate / adhesive layer / zeonore / adhesive layer / liquid crystal substance layer 1 / curing. A laminated film for an optical element comprising acrylic resin layer 1 / adhesive layer / separator was obtained.

  The obtained laminated film for optical elements was cut into a 5 cm square size, the separator was peeled off and bonded to a 2 mm thick soda glass, and autoclaved (50 ° C., 490 kPa, 20 minutes), and then subjected to the following test. Went.

(Heat shock test)
When a heat shock test in which 85 ° C. (30 minutes) and −40 ° C. (30 minutes) were alternately repeated was performed, no appearance abnormality such as cracking was observed even after 500 cycles.
(Rework test)
After applying a cutter blade edge to the corner of the chip bonded to the glass and then performing a rework test to peel the chip off, it peels cleanly at the interface between the adhesive layer and the glass, and abnormal peeling between other layers Was not recognized at all.

[Example 2]
Instead of the UV curable acrylic resin layer 2, a UV curable acrylic adhesive 3 having a Tg of 110 ° C. with 5 parts by weight of a fluorine surface modifier (Megafac F472SF, manufactured by Dainippon Ink Co., Ltd.) added. A laminated film for an optical element was obtained in the same manner as in Example 1 except that (Toagosei Co., Ltd.) was used.
A heat shock test and a rework test were performed in the same manner as in Example 1, but no abnormality was observed.

[Example 3]
Instead of the UV curable acrylic resin layer 2, a UV curable acrylic adhesive 4 having a Tg of 105 ° C. with 4 parts by weight of a silicone surface modifier (Paintad 32, manufactured by Toray Dow Corning Co., Ltd.) added. A laminated film for an optical element was obtained in the same manner as in Example 1 except that (Toagosei Co., Ltd.) was used.
A heat shock test and a rework test were performed in the same manner as in Example 1, but no abnormality was observed.

[Example 4]
A UV curable acrylic adhesive 5 (manufactured by Toagosei Co., Ltd.) having a glass transition temperature of 126 ° C. on the liquid crystal material layer 1 (surface opposite to the polyimide film) obtained in the preparation example is 5 μm thick. A TAC film having a thickness of 40 μm (manufactured by Fuji Film Co., Ltd.) having a corona-treated surface is laminated thereon, and the acrylic resin layer 5 is cured by UV irradiation of about 600 mJ. I let you. Thereafter, the liquid crystal material layer is transferred onto the TAC film by peeling the polyimide film from the laminate in which the TAC film / cured acrylic resin layer 5 / liquid crystal material layer 1 / polyimide film is integrated, and the TAC film / cured material is cured. A laminate comprising acrylic resin layer 5 / liquid crystal material layer 1 was obtained.

  Further, a UV curable acrylic adhesive 6 (manufactured by Toagosei Co., Ltd.) having a Tg = 54 ° C. was applied as a 5 μm thick acrylic resin layer 6 on the liquid crystal material layer 1 of the laminate. A 38 μm-thick PET film (manufactured by Toray Industries, Inc.) was laminated thereon, and the acrylic resin layer 6 was cured by UV irradiation of about 600 mJ to obtain a TAC film / cured acrylic resin layer 5 / liquid crystal substance layer 1 / A laminate (C) composed of cured acrylic resin layer 6 / PET film was obtained.

  Next, after peeling off the PET film of the laminate (C), a film having a 25 μm thick adhesive layer previously formed on a 38 μm thick separator is bonded to the surface of the cured acrylic resin layer 6, and the separator / A laminate (D) comprising pressure-sensitive adhesive layer / cured acrylic resin layer 6 / liquid crystal substance layer 1 / cured acrylic resin layer 5 / TAC film was obtained.

  Next, after peeling the TAC film side from the laminate (D) at the liquid crystal material layer 1 / cured acrylic resin layer 5 interface, a 40 μm thick ZEONOR film (Zeon Co., Ltd.) bonded in advance at a desired angle. And polarizing plate (manufactured by Sumitomo Chemical Co., Ltd.) via a 20 μm thick adhesive, polarizing plate / adhesive layer / Zeonor / adhesive layer / liquid crystal material layer 1 / cured acrylic resin layer A laminated film for an optical element comprising 6 / adhesive layer / separator was obtained.

  The obtained laminated film for optical elements was cut into a 5 cm square size, the separator was peeled off and bonded to soda glass having a thickness of 2 mm, followed by autoclaving (50 ° C., 490 kPa, 20 minutes), and then Example 1 The heat shock test and the rework test were conducted in the same manner as in the above. As a result, no abnormality was observed.

[Example 5]
Instead of the UV curable acrylic resin layer 5, a UV curable acrylic adhesive Tg = 108 ° C. with 6 parts by weight of a fluorine surface modifier (Surflon S-386, manufactured by Seimi Chemical Co., Ltd.) 7 A laminated film for an optical element was obtained in the same manner as in Example 4 except that (Toagosei Co., Ltd.) was used.
A heat shock test and a rework test were performed in the same manner as in Example 1, but no abnormality was observed.

[Example 6]
Instead of the UV curable acrylic resin layer 5, a UV curable acrylic adhesive 8 having a Tg of 112 ° C. with 3 parts by weight of a silicone surface modifier (Paintad 29, manufactured by Toray Dow Corning Co., Ltd.) added. A laminated film for an optical element was obtained in the same manner as in Example 4 except that (Toagosei Co., Ltd.) was used.
A heat shock test and a rework test were performed in the same manner as in Example 1, but no abnormality was observed.

[Comparative Example 1]
5 μm of UV curable acrylic adhesive 9 (manufactured by Toagosei Co., Ltd.) having a glass transition temperature (Tg) of 40 ° C. on the liquid crystal material layer 1 obtained in the preparation example (surface opposite to the polyimide film) A 50 μm thick polyethylene terephthalate (PET) film (manufactured by Toray Industries, Inc.) is laminated thereon, and the acrylic resin layer 9 is cured by UV irradiation of about 600 mJ. I let you. Thereafter, the liquid crystal material layer is transferred onto the PET film by peeling the polyimide film from the laminate in which the PET film / cured acrylic resin layer 9 / liquid crystal material layer 1 / polyimide film is integrated. A laminate composed of the acrylic resin layer 9 / liquid crystal material layer 1 was obtained.

  Further, a UV curable acrylic adhesive 10 (manufactured by Toagosei Co., Ltd.) having a Tg = 132 ° C. was applied to the liquid crystal material layer 1 of the laminate as an acrylic resin layer 10 to a thickness of 5 μm. A saponified 40 μm-thick triacetyl cellulose (TAC) film is laminated thereon, and the acrylic resin layer 10 is cured by UV irradiation of about 600 mJ to obtain a PET film / cured acrylic resin layer 9 / liquid crystal substance. A laminate (E) composed of layer 1 / cured acrylic resin layer 10 / saponified TAC film was obtained.

  Next, after peeling off the PET film of the laminate (E), a film in which a 25 μm thick adhesive layer was previously formed on a 38 μm thick separator was bonded to the surface of the cured acrylic resin layer 9, and the separator / A laminate (F) comprising pressure-sensitive adhesive layer / cured acrylic resin layer 9 / liquid crystal substance layer 1 / cured acrylic resin layer 10 / saponified TAC film was obtained.

Next, after peeling the saponified TAC film from the laminate (F), a 40 μm thick ZEONOR film (manufactured by ZEON Co., Ltd.) and a polarizing plate (manufactured by Sumitomo Chemical Co., Ltd.) bonded in advance at a desired angle Is bonded via a pressure-sensitive adhesive having a thickness of 20 μm, thereby polarizing plate / pressure-sensitive adhesive layer / zeonore / pressure-sensitive adhesive layer / cured acrylic resin layer 10 / liquid crystal substance layer 1 / cured acrylic resin layer 9 / pressure-sensitive adhesive layer. / The laminated film for optical elements consisting of a separator was obtained.
The obtained laminated film for optical elements was cut into a 5 cm square size, and a heat shock test and a rework test were conducted in the same manner as in Example 1.
As a result of the heat shock test, cracks occurred in the liquid crystal layer material layer and the cured acrylic resin layer after 150 cycles. Further, in the rework test, some peeling occurred at the interface between the liquid crystal material layer and the cured acrylic resin layer.

[Comparative Example 2]
5 μm of UV curable acrylic adhesive 10 (manufactured by Toagosei Co., Ltd.) having a glass transition temperature (Tg) of 132 ° C. on the liquid crystal material layer 1 obtained in the preparation example (surface opposite to the polyimide film). A 40 μm thick triacetyl cellulose (TAC) film having a surface previously saponified is laminated thereon, and the acrylic resin layer 10 is applied by UV irradiation of about 600 mJ. Cured. Thereafter, the liquid crystal material layer is transferred onto the saponified TAC film by peeling the polyimide film from the laminate in which the saponified TAC film / cured acrylic resin layer 10 / liquid crystal material layer 1 / polyimide film is integrated, and the saponified TAC is transferred. A laminate comprising film / cured acrylic resin layer 10 / liquid crystal material layer 1 was obtained.

  Further, a UV curable acrylic adhesive 9 (manufactured by Toagosei Co., Ltd.) having a Tg = 40 ° C. was applied to the liquid crystal material layer 1 of the laminate as an acrylic resin layer 9 to a thickness of 5 μm. A 50 μm thick polyethylene terephthalate (PET) film (manufactured by Toray Industries, Inc.) is laminated thereon, the acrylic resin layer 9 is cured by UV irradiation of about 600 mJ, and saponified TAC film / cured acrylic resin layer 10 / liquid crystal. A laminate (G) comprising material layer 1 / cured acrylic resin layer 9 / PET film was obtained.

  Next, after peeling off the PET film of the laminate (G), a film in which a 25 μm thick adhesive layer was previously formed on a 38 μm thick separator was bonded to the surface of the cured acrylic resin layer 9, and the separator / A laminate (H) composed of pressure-sensitive adhesive layer / cured acrylic resin layer 9 / liquid crystal substance layer 1 / cured acrylic resin layer 10 / saponified TAC film was obtained.

Next, after peeling the saponified TAC film from the laminate (H), a 40 μm-thick ZEONOR film (manufactured by ZEON Co., Ltd.) and a polarizing plate (manufactured by Sumitomo Chemical Co., Ltd.) bonded in advance at a desired angle Is bonded via a pressure-sensitive adhesive having a thickness of 20 μm, thereby polarizing plate / pressure-sensitive adhesive layer / zeonore / pressure-sensitive adhesive layer / cured acrylic resin layer 10 / liquid crystal substance layer 1 / cured acrylic resin layer 9 / pressure-sensitive adhesive layer. / The laminated film for optical elements consisting of a separator was obtained.
The obtained laminated film for optical elements was cut into a 5 cm square size, and a heat shock test and a rework test were conducted in the same manner as in Example 1.
As a result of the heat shock test, cracks occurred in the liquid crystal layer material layer and the cured acrylic resin layer after 150 cycles. Further, in the rework test, some peeling occurred at the interface between the liquid crystal material layer and the cured acrylic resin layer.

[Comparative Example 3]
A laminated film for an optical element was obtained in the same manner as in Comparative Example 1 except that adhesives having Tg = 52 ° C. and Tg = 63 ° C. were used in place of the UV curable acrylic resin layers 9 and 10, respectively. .
As a result of the heat shock test, cracks occurred in the liquid crystal layer material layer and the cured acrylic resin layer after 250 cycles. Further, in the rework test, some peeling occurred at the interface between the liquid crystal material layer and the cured acrylic resin layer.

[Comparative Example 4]
A laminated film for an optical element was obtained in the same manner as in Comparative Example 2 except that adhesives having Tg = 96 ° C. and Tg = 84 ° C. were used in place of the UV curable acrylic resin layers 9 and 10, respectively. .
As a result of the heat shock test, cracks occurred in the liquid crystal layer material layer and the cured acrylic resin layer after 50 cycles. Further, in the rework test, some peeling occurred at the interface between the liquid crystal material layer and the cured acrylic resin layer.

  Table 1 summarizes the evaluation results of the heat shock test and the rework test of the laminated films for optical elements obtained in Examples 1 to 6 and Comparative Examples 1 to 4.

Claims (7)

  After the liquid crystal material layer with the liquid crystal alignment fixed formed on the alignment substrate is adhered to the releasable substrate via the adhesive 1, the alignment substrate is peeled off to make the liquid crystal material layer a removable substrate. After the transfer, the laminate (I) comprising the releasable substrate / adhesive layer 1 / liquid crystal material layer / adhesive layer 2 / temporary substrate is obtained by adhering to the temporary substrate via the adhesive 2 Step, a second step of peeling the releasable substrate from the laminate (I), and then peeling between the liquid crystal material layer / adhesive layer 2 to obtain a liquid crystal film comprising an adhesive layer 1 / a liquid crystal material layer A method for producing a liquid crystal film, which is obtained through at least each step of the third step.   After the liquid crystal material layer with the liquid crystal alignment fixed formed on the alignment substrate is adhered to the temporary substrate via the adhesive 1, the alignment substrate is peeled off and the liquid crystal material layer is transferred to the temporary substrate. A first step of obtaining a laminate (II) comprising a temporary substrate / adhesive layer 1 / liquid crystal material layer / adhesive layer 2 / removable substrate by adhering to the removable substrate via the adhesive 2; A second step of peeling the releasable substrate from the laminate (II), and then a third step of obtaining a liquid crystal film comprising the liquid crystal material layer / adhesive layer 2 by peeling between the adhesive layer 1 and the liquid crystal material layer. A method for producing a liquid crystal film, which is obtained through at least each of the steps.   3. The liquid crystal material layer in which the liquid crystal alignment is fixed is made of a polymer liquid crystal material that is aligned in a liquid crystal at a temperature equal to or higher than the liquid crystal transition point and is in a glass state at a temperature equal to or lower than the liquid crystal transition point. The manufacturing method of the liquid-crystal film as described in any one of.   3. The method for producing a liquid crystal film according to claim 1, wherein the liquid crystal material layer in which the liquid crystal alignment is fixed is a liquid crystal aligned low molecular liquid crystal material that is photocrosslinked or thermally crosslinked.   The method for producing a liquid crystal film according to claim 1, wherein the temporary substrate or the removable substrate has optical isotropy.   3. The method for producing a liquid crystal film according to claim 1, wherein the adhesive to be bonded to the temporary substrate contains a silicone-based or fluorine-based surface modifier.   A laminated film for an optical element, wherein the liquid crystal film produced by the method according to claim 1 is laminated with a polarizing plate or a retardation plate via an adhesive or an adhesive.