JP5932234B2 - Polarizing element and manufacturing method thereof - Google Patents

Description

  The present invention relates to a polarizing element having a liquid crystal layer in which the orientation of a liquid crystalline compound is fixed on one surface of a polarizer, and a method for producing the same.

  An optical film having birefringence is used as a member for realizing an improvement in contrast and an increase in viewing angle in an image display device such as a liquid crystal display device. As an example of such an optical film, a liquid crystal layer in which the orientation of a liquid crystal compound is fixed is formed on a substrate. Since the liquid crystalline compound has orientation, for example, when applied to the surface of a substrate such as a stretched film or an oriented film, the molecules are oriented according to the orientation regulating force, and the coated film exhibits birefringence characteristics (for example, , See Patent Document 1).

  The liquid crystal layer in which the orientation of the liquid crystal compound is fixed has a large birefringence, and an equivalent retardation can be obtained with a small thickness compared to a stretched film of a polymer film. It has been attracting attention with the trend of climatization. In addition, by fixing the alignment of the liquid crystalline compound using a mask pattern or the like, a layer having a different alignment state can be formed for each minute region. Therefore, a polarizing element having such a liquid crystal layer is formed on the right eye for each pixel. The present invention can also be applied to a space-division type three-dimensional display in which a work image and a left-eye image appear.

  In general, such a liquid crystal layer is formed on a substrate and then bonded or transferred onto an optical member such as a polarizing plate, and is incorporated into a liquid crystal display device or the like as a polarizing element with a liquid crystal layer. Such a polarizing element 21 with a liquid crystal layer has, for example, a laminated structure as shown in FIG. In FIG. 4, a liquid crystal layer 4 is formed on one transparent protective film 2 of a polarizing plate in which transparent protective films 2 and 3 are bonded to both surfaces of a polarizer 1 via adhesive layers 12 and 13, respectively. As a polarizing element with a liquid crystal layer, there is an element having a laminated structure other than the form shown in FIG. 4, but in general, a transparent protective film 2 is bonded to the polarizer 1, and a liquid crystal layer 4 is formed thereon. Has been.

  On the other hand, from the viewpoint of thinning a polarizing element having a birefringent layer, it has been proposed to bond a polarizer and an amorphous polymer layer as a birefringent layer without using a transparent protective film (for example, Patent Documents). 2). Similarly, in a polarizing element with a liquid crystal layer, if a polarizer and a liquid crystal layer are bonded together without using a transparent protective film, the polarizing element can be reduced in thickness and cost can be reduced. However, when the liquid crystal layer and the polarizer are bonded directly via the adhesive layer, the adhesion at the interface between the liquid crystal layer and the adhesive layer is not sufficient, and the liquid crystal layer is used when used under high temperature and high humidity. And peeling may occur between the polarizer and the polarizer. Further, when a polarizing element containing defects is peeled from the glass substrate of the liquid crystal cell, peeling is likely to occur at the interface between the liquid crystal layer and the polarizer, and reworkability tends to be poor.

Patent No. 2631015 JP 2003-344657 A

  In view of the above, an object of the present invention is to provide a polarizing element in which the adhesion between a polarizer and a liquid crystal layer is improved and the polarizer and the liquid crystal layer are laminated without using a transparent protective film.

  As a result of intensive studies by the present inventors, it was found that the adhesion to the polarizer can be improved by forming the organosilicon compound layer by treating the surface of the liquid crystal layer with a silane coupling agent, leading to the present invention. It was.

  The present invention relates to a polarizing element comprising a liquid crystal layer in which the orientation of a liquid crystalline compound is fixed on a polyvinyl alcohol film polarizer. The liquid crystal layer contains a liquid crystal compound and a surfactant, and an organic silicon compound layer obtained using a silane coupling agent is formed on the surface of the liquid crystal layer on the polarizer side. In the polarizing element of the present invention, the polarizer and the organosilicon compound layer on the surface of the liquid crystal layer are bonded together via a first adhesive layer.

  A transparent protective film may be bonded to the other surface of the polarizer via a second adhesive layer. The thickness of the organosilicon compound layer is preferably 30 nm or less.

  The surfactant contained in the liquid crystal layer is preferably a silicone-based surfactant or a fluorine-based surfactant.

  Furthermore, this invention relates to the manufacturing method of the said polarizing element. The production method of the present invention includes a step of preparing a liquid crystal layer containing a liquid crystal compound and a surfactant and fixing the alignment of the liquid crystal compound, and treating the surface of the liquid crystal layer with a silane coupling agent solution to form an organosilicon compound A step of forming a layer, and a step of bonding the organic silicon compound layer forming surface of the liquid crystal layer to one surface of the polyvinyl alcohol-based film polarizer via the first adhesive layer.

  According to the present invention, the surface of the liquid crystal layer is treated with a silane coupling agent to form an organosilicon compound layer, and this organosilicon compound layer forming surface is bonded to the polarizer via the adhesive layer. According to this configuration, even when the polarizer and the liquid crystal layer are bonded without using the transparent protective film, a polarizing element having high adhesion between the liquid crystal layer and the polarizer can be obtained. It can contribute and has excellent reworkability.

It is a schematic sectional drawing of the polarizing element by one Embodiment of this invention. It is a schematic sectional drawing of the polarizing element by one Embodiment of this invention. It is a schematic sectional drawing of the polarizing element by one Embodiment of this invention. It is a schematic sectional drawing of one form of the polarizing element by a prior art.

  The present invention will be described below with reference to the drawings. As shown in FIG. 1, the polarizing element 20 of the present invention has a liquid crystal layer 4 on one surface of a polarizer 1, and the first between the polarizer 1 and the liquid crystal layer 4 from the side of the polarizer 1. It has an adhesive layer 12 and an organosilicon compound layer 14. That is, an organosilicon compound layer 14 is formed on the surface of the liquid crystal layer 4, and this is bonded onto the polarizer 1 through the first adhesive layer 12. The configuration of the other surface of the polarizer 1 is not particularly limited. In FIG. 1, the form by which the transparent protective film 3 was bonded together through the 2nd adhesive bond layer 13 is shown.

[Polarizer]
The polarizer 1 is made of a polyvinyl alcohol film. Such a polarizer can be obtained, for example, by adsorbing a dichroic substance such as iodine or a dichroic dye on a polyvinyl alcohol film and stretching the film uniaxially. Among these, from the viewpoint of having a high degree of polarization and the viewpoint of adhesiveness with the liquid crystal layer, a polarizer made of a polyvinyl alcohol film containing iodine is preferably used. Polyvinyl alcohol or a derivative thereof is used as a material for the polyvinyl alcohol film applied to the polarizer. Derivatives of polyvinyl alcohol include polyvinyl formal, polyvinyl acetal, and the like, olefins such as ethylene and propylene, unsaturated carboxylic acids such as acrylic acid, methacrylic acid, and crotonic acid, and their alkyl esters and acrylamide. Things. Polyvinyl alcohol having a polymerization degree of about 1000 to 10000 and a saponification degree of about 80 to 100 mol% is generally used.

  The polyvinyl alcohol film may contain additives such as a plasticizer. Examples of the plasticizer include polyols and condensates thereof, and examples thereof include glycerin, diglycerin, triglycerin, ethylene glycol, propylene glycol, and polyethylene glycol. The amount of the plasticizer used is not particularly limited, but is preferably 20% by weight or less in the polyvinyl alcohol film.

  The polyvinyl alcohol film (unstretched film) is subjected to at least a uniaxial stretching process and a dyeing process according to a conventional method. Furthermore, boric acid treatment, iodine ion treatment, or the like can be performed. The polyvinyl alcohol film (stretched film) subjected to these treatments is dried according to a conventional method to become a polarizer.

  The stretching method in the uniaxial stretching treatment is not particularly limited, and either a wet stretching method or a dry stretching method can be employed. Examples of the stretching means of the dry stretching method include an inter-roll stretching method, a heated roll stretching method, and a compression stretching method. Stretching can also be performed in multiple stages. In the stretching means, the unstretched film is usually heated. Usually, an unstretched film having a thickness of about 30 to 150 μm is used. The stretch ratio of the stretched film can be appropriately set according to the purpose, but the stretch ratio (total stretch ratio) is about 2 to 8 times, preferably 3 to 6.5 times, more preferably 3.5 to 6 times. Is desirable. The thickness of the stretched film is preferably about 5 to 40 μm.

  When iodine dyeing is performed as the dyeing process, the dyeing process is performed by immersing the polyvinyl alcohol film in an iodine solution containing iodine and potassium iodide. The iodine solution is usually an iodine aqueous solution, and contains iodine and potassium iodide as a dissolution aid. The iodine concentration is about 0.01 to 1% by weight, preferably 0.02 to 0.5% by weight. The potassium iodide concentration is about 0.01 to 10% by weight, and further 0.02 to 8% by weight. It is preferable to use it.

  In the iodine dyeing treatment, the temperature of the iodine solution is usually about 20 to 50 ° C, preferably 25 to 40 ° C. The immersion time is usually about 10 to 300 seconds, preferably 20 to 240 seconds. In the iodine dyeing treatment, the iodine content and potassium content in the polyvinyl alcohol film are within the above ranges by adjusting the conditions such as the concentration of the iodine solution, the immersion temperature of the polyvinyl alcohol film in the iodine solution, and the immersion time. Adjust as follows. The iodine dyeing process may be performed at any stage before the uniaxial stretching process, during the uniaxial stretching process, or after the uniaxial stretching process.

  The boric acid treatment is performed by immersing a polyvinyl alcohol film in an aqueous boric acid solution. The boric acid concentration in the boric acid aqueous solution is about 2 to 15% by weight, preferably 3 to 10% by weight. The aqueous boric acid solution can contain potassium ions and iodine ions with potassium iodide. The potassium iodide concentration in the boric acid aqueous solution is preferably about 0.5 to 10% by weight, more preferably 1 to 8% by weight. By immersing in a boric acid aqueous solution containing potassium iodide, it is possible to obtain a lightly colored polarizer, that is, a so-called neutral gray polarizer having a substantially constant absorbance over almost the entire wavelength range of visible light.

  For the iodine ion treatment, for example, an aqueous solution containing iodine ions with potassium iodide or the like is used. The potassium iodide concentration is preferably about 0.5 to 10% by weight, more preferably 1 to 8% by weight. In the iodine ion impregnation treatment, the temperature of the aqueous solution is usually about 15 to 60 ° C, preferably 25 to 40 ° C. The immersion time is usually about 1 to 120 seconds, preferably 3 to 90 seconds. The iodine ion treatment may be performed at any stage without particular limitation as long as it is before the drying step, and can also be performed after water washing described later.

  The treated polyvinyl alcohol film (stretched film) can be subjected to a water washing step and a drying step according to a conventional method. The water washing step is usually performed by immersing a polyvinyl alcohol film in pure water. The water washing temperature is usually in the range of 5 to 50 ° C, preferably 10 to 45 ° C, more preferably 15 to 40 ° C. The immersion time is usually about 10 to 300 seconds, preferably about 20 to 240 seconds.

[Liquid crystal layer]
The liquid crystal layer 4 is a layer in which the alignment of the liquid crystal compound is fixed. As the liquid crystalline compound used for forming the liquid crystal layer, either a compound having a negative refractive index anisotropy or a compound having a positive refractive index anisotropy can be used. Examples of the liquid crystalline compound having negative refractive index anisotropy include discotic liquid crystal compounds. The discotic liquid crystal compound is C.I. Destrade et al., Mol. Cryst. 71, 111 (1981), benzene derivatives and B.I. Kohne et al., Angew. Chem. 96, page 70 (1984) and the cyclohexane derivatives described in J. Am. M.M. Lehn et al. Chem. Commun. , 1794 (1985), J. Am. Zhang et al., J. Am. Chem. Soc. 116, 2655 (1994), such as azacrown and phenylacetylene macrocycles, etc., which are generally used as a mother nucleus at the center of a molecule, and are linear alkyl groups, alkoxy groups, substituted A structure in which a benzoyloxy group or the like is radially substituted as a straight chain thereof exhibits liquid crystallinity and includes what is generally called a discotic liquid crystal. However, the molecule itself is not limited to the above description as long as the molecule itself has negative uniaxiality and can give a certain orientation. In the present invention, as the discotic liquid crystal compound, one having a polymerizable unsaturated group (for example, acryloyl group, methacryloyl group, vinyl group, allyl group, etc.) that undergoes a curing reaction with heat, light or the like is usually used. It is done.

  On the other hand, examples of the liquid crystalline compound having positive refractive index anisotropy include rod-shaped nematic liquid crystalline compounds. A “rod-shaped liquid crystal compound” has a mesogenic group in its molecular structure, and the refractive index in the major axis direction of the mesogenic group is larger than that in the minor axis direction. Or a compound exhibiting a liquid crystal phase by the action of a certain amount of solvent. As the dedicated liquid crystal compound, any appropriate compound can be selected, but those which show a crystalline or glass state at room temperature and develop a nematic liquid crystal phase at a high temperature can be suitably used. The rod-shaped liquid crystal compound exhibits a liquid crystal phase before film formation, but after film formation, for example, a network structure may be formed by a cross-linking reaction and no liquid crystal phase may be exhibited. By using the rod-like liquid crystal compound having the above properties, for example, the alignment state can be fixed by cooling or crosslinking after forming a hybrid alignment in a state showing a liquid crystal phase.

The mesogenic group is a structural part for forming a liquid crystal phase and usually contains a ring structural unit. Specific examples of the mesogenic group include a biphenyl group, a phenylbenzoate group, a phenylcyclohexane group, an azoxybenzene group, an azomethine group, an azobenzene group, a phenylpyrimidine group, a diphenylacetylene group, a diphenylbenzoate group, a bicyclohexane group, and a cyclohexylbenzene group. And terphenyl group. In addition, the terminal of these ring structural units may have substituents, such as a cyano group, an alkyl group, an alkoxy group, a halogen group, for example. Among them, those having a biphenyl group or a phenylbenzoate group as the mesogenic group are preferably used.

  In the present invention, the liquid crystal compound in the final liquid crystal layer is not necessarily the same as the liquid crystal compound described above, and includes those that lose liquid crystallinity due to reaction of a polymerizable unsaturated group or the like. As the liquid crystalline compound, any of a liquid crystalline polymer, a liquid crystalline prepolymer, and a liquid crystalline monomer can be used depending on the desired optical characteristics and the like. For example, when producing a so-called A plate in which the liquid crystal compound is aligned in a direction parallel to the substrate surface, that is, homogeneously aligned, it is preferable to use a homogeneously aligned nematic liquid crystal compound. In the case of producing a so-called O-plate with nematic hybrid alignment in which the tilt angle of the liquid crystal compound is continuously changed along the thickness direction of the liquid crystal layer, the homeotropic alignment liquid crystal compound is used alone. Alternatively, it is preferably used in combination with the above-mentioned homogeneous alignment liquid crystalline compound. In addition, when obtaining an optical film having a twisted nematic alignment (also referred to as cholesteric alignment) in which the alignment direction of the liquid crystal compound is continuously twisted in the thickness direction of the liquid crystal layer, the above homogeneous alignment property is obtained. A liquid crystal compound and a chiral agent can be used in combination.

  As a coating liquid containing a liquid crystalline compound, a solution obtained by dissolving a liquid crystalline compound in a solvent is preferably used. As a solvent for forming the coating liquid, the liquid crystalline compound, the polymerization initiator and other additives are excellent in solubility, and the orientation of the liquid crystalline compound is lowered when the coating liquid is applied on the substrate. There is no particular limitation as long as it does not cause the problem. Specifically, aromatic hydrocarbons such as benzene, toluene, xylene, methoxybenzene, 1,2-dimethoxybenzene, chloroform, dichloromethane, carbon tetrachloride, dichloroethane, tetrachloroethane, trichloroethylene, tetrachloroethylene, chlorobenzene, orthodichlorobenzene, etc. Halogenated hydrocarbons, phenols such as phenol and parachlorophenol, ethers such as diethyl ether, dibutyl ether, tetrahydrofuran, anisole, dioxane, tetrahydrofuran, acetone, methyl isobutyl ketone, methyl ethyl ketone, cyclohexanone, cyclopentanone, 2 -Pentanone, 3-pentanone, 2-hexanone, 3-hexanone, 2-heptanone, 3-heptanone, 4-heptanone, 2,6- Ketones such as methyl-4-heptanone, 2-pyrrolidone, N-methyl-2-pyrrolidone, n-butanol, 2-butanol, cyclohexanol, isopropyl alcohol, t-butyl alcohol, glycerin, ethylene glycol, triethylene glycol, Ethylene glycol monomethyl ether, diethylene glycol dimethyl ether, propylene glycol, dipropylene glycol, alcohols such as 2-methyl-2,4-pentanediol, amides such as dimethylformamide and dimethylacetamide, nitriles such as acetonitrile and butyronitrile, methyl cellosolve Cellosolves such as methyl cellosolve and ethyl cellosolve, and esters such as ethyl acetate, butyl acetate and methyl lactate can be used. In addition, methylene chloride, carbon disulfide, ethyl cellosolve, butyl cellosolve, and the like can be given as examples of the solvent, but are not limited thereto.

  The coating solution preferably contains a surfactant. As the surfactant, various compounds such as silicone, fluorine, polyether, acrylic, and titanate can be used. In particular, in the present invention, from the viewpoint of reducing the surface tension of the liquid crystal layer and increasing the adhesion to the organosilicon compound layer formed on the surface of the liquid crystal layer, a silicone surfactant or a fluorine surfactant is preferable. Used for.

Examples of the silicone-based surfactant include those containing an organically modified polysiloxane having a hydrophilic group. Examples of the hydrophilic group include a hydroxyl group, a carboxylic acid group, a sulfonic acid group, an acrylic group, an ester group, an ether group, — (CH ₂ CH ₂ O) _n —R (n is an integer of 5 to 30, and R is hydrogen or carbon. number 1-6 alkyl _{group), - (CH 2 CHOHCH 2} ) n -H (n is include 5-30 integer), and the like. Examples of the surfactant containing such a siloxane compound include a polyether-modified product of polydimethylsiloxane. Silicone surfactants include BYK-Chemie's “BYK” series, Toray Dow Corning's product name “Tole Silicone” series, Momentive Performance Materials' product name “TSF” series, Shin-Etsu. Silicone “KP” series, “KF” series and the like are commercially available.

Examples of the fluorine-based surfactant include those containing a fluorine-containing compound having a fluorine-substituted alkyl group and a hydrophilic group. A fluorine-substituted alkyl group is one in which part or all of the hydrogen atoms of a linear or branched alkyl group are substituted with fluorine atoms. The fluorine-substituted alkyl group preferably has 3 to 30 carbon atoms. In the fluorine-substituted alkyl group, 50% or more of hydrogen atoms contained in the alkyl group are preferably substituted, more preferably 60% or more are substituted, and 80% or more are further substituted. Preferably, 90% or more is more preferably substituted, and most preferably 100% substituted. As the hydrophilic group, a hydroxyl group, a carboxylic acid group, a sulfonic acid group, an acrylic group, an ester group, an ether group, — (CH ₂ CH ₂ O) _n R (n is an integer of 5 to 30, R is hydrogen or carbon number) 1-6 alkyl _{group), - (CH 2 CHOHCH 2} ) n -H (n is include 5-30 integer), and the like. Examples of such a fluorine-based compound include perfluoroalkyl sulfonic acid (CF ₃ (CF ₂ ) _n SO ₃ H), perfluoroalkyl carboxylic acid (CF ₃ (CF ₂ ) _m COOH), and fluorine telomer alcohol (F (CF _{2) m CH 2 CH 2 OH} ), perfluoroalkyl ethylene oxide adduct _{((CF 3 (CF 2)} m -. (CH 2 CH 2 O) n H , and the like (m, and n is an integer) among others Perfluoroalkylethylene oxide adducts are most preferably used as the fluorosurfactant, such as “MegaFuck” series manufactured by DIC, “Fluorad” series manufactured by 3M, and manufactured by Imperial Chemical Industry Co., Ltd. The “Monflor” series, the “Zonyls” series manufactured by DuPont, etc. are commercially available. It is.

  The content of the surfactant in the coating solution is preferably 0.001 to 0.2 part by weight with respect to 100 parts by weight of the liquid crystal compound, and 0.005 to 0.15 part by weight. More preferably, it is 0.01 parts by weight to 0.1 parts by weight. If the content of the surfactant is excessively small, the effect of lowering the surface tension of the liquid crystal layer cannot be sufficiently obtained, and sufficient adhesion between the liquid crystal layer and the polarizer may not be ensured. Further, when the amount of the surfactant is excessively large, the surfactant is unevenly distributed in the coating layer, and the uniformity of the film thickness of the liquid crystal layer may be lowered.

  When a liquid crystalline prepolymer or a liquid crystalline monomer is used as the liquid crystalline compound, it is preferable that the coating liquid contains a polymerization initiator from the viewpoint of advancing the polymerization reaction. There is no restriction | limiting in particular as a polymerization initiator, The photoinitiator which consists of a single compound may be sufficient, and what mixed 2 or more types of different polymerization initiators may be sufficient. The polymerization initiator is preferably a photopolymerization initiator, and examples thereof include acetophenone compounds, benzoin compounds, benzophenone compounds, and thioxanthone compounds. Also, for example, trade names “Irgacure 651”, “Irgacure 184”, “Darocur 1173”, “Irgacure 500”, “Irgacure 2959”, “Irgacure 907”, “Irgacure 369”, “Irgacure 819” manufactured by Ciba Geigy A photopolymerization initiator such as “Irgacure 784” may be used. Further, Merck's trade names “Darocur 953” and “Darocur 1116”, and Nippon Kayaku's trade names “Kaya Cure MBP”, “Kaya Cure CTX”, “Kaya Cure DITX”, “Kaya Cure CTX”, “Kaya Cure DETX” It is also possible to use “Kayacure RTX” or the like.

  The coating solution may contain components other than the liquid crystal compound, the surfactant, the polymerization initiator, and the solvent. For example, when forming a liquid crystal layer in which a liquid crystal compound is tilt-aligned, it is preferable to include a homeotropic liquid crystal compound. Although it does not restrict | limit especially as a liquid crystal polymer of homeotropic orientation, It contains the monomer unit containing the liquid crystalline fragment side chain which has positive refractive index anisotropy, and the monomer unit containing a non-liquid crystalline fragment side chain It is preferable to use a side chain type liquid crystal polymer. As such a liquid crystal compound, for example, those described in JP-A No. 2003-149441 can be used. Further, when obtaining a cholesteric alignment liquid crystal layer, it is preferable to add a chiral agent.

  The substrate 104 to which the coating liquid is applied preferably has an alignment regulating force that aligns the liquid crystalline compound in a predetermined direction. As such a substrate, for example, a stretched film that has been subjected to stretching treatment or a substrate having an alignment film on the substrate is preferably used. Examples of the alignment film include those obtained by rubbing a thin film made of polyimide, polyvinyl alcohol, or the like, or those obtained by obliquely depositing silicon oxide. By using such a base material, the liquid crystalline compound can be aligned with high uniformity in a predetermined direction.

  The base material 104 is not particularly limited as long as it can orient the liquid crystal compound applied on the surface, and a plastic film, a flexible metal plate (metal foil), a glass plate, or the like is used. be able to. The substrate may be transparent or opaque.

  The method for applying the coating liquid containing the liquid crystal compound on the substrate 104 is not particularly limited, and is a dip coating method, curtain coating method, bar coating method, rod coating method, roll coating method (forward roll coater, reverse roll). Conventionally known methods such as a coater, a gravure coater) and a die coating method (extrusion coater (slot coater), slide coater, slit die coater) can be appropriately used. The coating thickness can be appropriately designed so that the liquid crystal layer after drying has desired optical properties.

  Thus, the coating layer formed on the base material 104 becomes the liquid crystal layer 4 exhibiting optical anisotropy by fixing the orientation of the liquid crystal compound. In the case of using a liquid crystalline polymer as the liquid crystalline compound, the coating liquid is applied to the surface of the base material, and then heated and dried until it reaches a temperature range (liquid crystal phase transition temperature) showing a liquid crystal phase. Thereafter, by rapidly cooling to near room temperature, the orientation of the liquid crystalline compound is fixed and exhibits optical anisotropy. When using a liquid crystalline prepolymer or a liquid crystalline monomer, after applying the coating liquid to the substrate surface, it is heated and dried until it reaches a temperature range (liquid crystal phase transition temperature) showing a liquid crystal phase. Thereafter, the liquid crystalline compound is polymerized (crosslinked) by being rapidly cooled to near room temperature and irradiated with an actinic ray such as ultraviolet rays, and the alignment state of the liquid crystalline compound is fixed and exhibits optical anisotropy. In addition, from the viewpoint of improving the orientation of the liquid crystal compound in a predetermined direction, a light beam polarized in a predetermined direction can be irradiated as the active light beam such as the ultraviolet ray.

[Silane coupling agent treatment and organosilicon compound layer]
The liquid crystal layer is bonded to a polarizer to form a polarizing element. The liquid crystal layer 4 and the polarizer 1 are bonded together using the adhesive layer 12. In the present invention, prior to the bonding between the liquid crystal layer and the polarizer, the surface of the liquid crystal layer 4 is coated with a silane coupling agent. The organic silicon compound layer 14 is formed by processing. By bonding the surface on which the organosilicon compound layer 14 is formed to the polarizer 1, the adhesion between them can be improved.

  As the silane coupling agent, those containing an organosilicon compound are preferable. As such a silane coupling agent, conventionally known ones can be used, and examples thereof include compounds represented by the following general formula (I). .

In the general formula (I), R ¹ , R ² and R ³ represent, for example, a hydrogen atom, an alkoxy group or an alkyl group, and at least one of them is an alkoxy group. R ¹ , R ² and R ³ may be the same or different, but it is preferable that all of them are alkoxy groups. n represents, for example, an integer of 1 to 10, preferably an integer of 1 to 5.
X is, for example, a haloalkyl group, a mercapto group, an alkylsulfanyl group, an amino group, an isocyanato group, a ureido group, a group represented by the following general formula (a), or a group represented by the following general formula (b).

In the general formula (a), Y ¹ , Y ² , Y ³ and Z ¹ are optional substituents. In the general formula (b), Y ⁴ , Y ⁵ , Y ⁶ and Z ² are optional substituents. It is a group.

Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, an isobutoxy group, a tert-butoxy group, a pentyloxy group, and a hexyloxy group, preferably a methoxy group and an ethoxy group It is a group. In addition, R ¹ , R ^2, and R ³ may be a hydroxyl group by a hydrolysis reaction in addition to an alkoxy group, and in this case, at least one of R ¹ , R ^2, and R ³ , Or the group which becomes all hydroxyl groups by a hydrolysis reaction may be sufficient.

In the general formula (I), when X is the general formula (a), examples of Y ¹ , Y ² and Y ³ include a hydrogen atom, an alkyl group and an aryl group, and these are the same. Z ¹ may be different, and examples of Z ¹ include a single bond, the following chemical formula (1a), the following chemical formula (2a), and the following chemical formula (3a).

In the general formula (I), when X is the general formula (b), examples of Y ⁴ , Y ⁵ and Y ⁶ include a hydrogen atom, an alkyl group and an aryl group, and these are the same. Z ² may be different, and examples of Z ² include a single bond, the chemical formula (1a), the chemical formula (2a), and the chemical formula (3a).

  In the general formula (I), the “alkyl” moiety such as the alkyl group, the haloalkyl group and the alkylsulfanyl group represents, for example, a linear or branched alkyl having 1 to 6 carbon atoms. Specific examples thereof include methyl, Examples include ethyl, n-propyl, isopropyl, butyl, isobutyl, t-butyl, pentyl, hexyl and the like. Among these, a linear or branched alkyl group having 1 to 4 carbon atoms is preferable, and methyl is particularly preferable. Examples of the “halogen” in the haloalkyl group include fluorine, chlorine, bromine, iodine and the like, and examples of the haloalkyl group include a chloromethyl group, a fluoromethyl group, a methyl iodide group, a trifluoromethyl group, Examples include chloroethyl group, fluoroethyl group, ethyl iodide group, chloropropyl group and the like. As said aryl group, a C6-C20 aromatic hydrocarbon group is mentioned, for example, A phenyl group, a naphthyl group, an anthranyl group etc. are preferable especially.

  Specific examples of the silane coupling agent represented by the general formula (I) include γ-acryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, and 3-methacrylic acid. Loxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, 3-chloropropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3- Mercaptopropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane and the like can be mentioned, among which γ-acryloxypropyltrimethoxysilane is preferable. These may be used alone or in combination of two or more.

  The silane coupling agent preferably has an unsaturated hydrocarbon group. Examples of the silane coupling agent having an unsaturated hydrocarbon group include a silane coupling agent containing a vinyl group. Specific examples thereof include 3-methacryloxypropyltrimethoxysilane and 3-acryloxypropyltrimethoxy. Silane etc. are mentioned.

  By treating the surface of the liquid crystal layer 4 with a silane coupling agent, the organosilicon compound layer 14 is formed on the surface of the liquid crystal layer. The formation method of the organic silicon compound layer is not particularly limited, and a method of immersing the substrate on which the liquid crystal layer is formed in a solution of the silane coupling agent, or a method of drying after applying the silane coupling agent solution on the liquid crystal layer Etc. From the viewpoint of controlling the thickness of the organosilicon compound layer, a method of applying a silane coupling agent solution on the liquid crystal layer and then drying it is preferable. As a method for applying the silane coupling agent solution, conventionally known methods such as a dip coating method, a curtain coating method, a bar coating method, a rod coating method, a roll coating method, and a die coating method can be appropriately used.

  The solvent of the silane coupling agent solution is not particularly limited, and a known one can be used. For example, acidic water or an alcohol solvent is particularly preferable because the solubility of the silane coupling agent is high. Moreover, after drying the said silane coupling agent solution, the affinity of a liquid crystal layer and an organosilicon compound layer can be improved more by heating. The heating temperature is not particularly limited, but when a thermotropic liquid crystalline compound is used as the liquid crystal layer, it is preferable to perform heating within a range that does not change the alignment state of the liquid crystal. The heating temperature is, for example, 40 to 150 ° C, preferably 50 to 130 ° C, more preferably 60 to 120 ° C. The heating time is not particularly limited, but is, for example, 1 minute to 10 minutes, preferably 2 minutes to 6 minutes.

  The silane coupling agent treatment of the liquid crystal layer can be performed on the liquid crystal layer 4 formed on the base material 104 or after the liquid crystal layer 4 is peeled from the base material 104. Further, the silane coupling agent treatment may be performed after the liquid crystal layer is transferred onto a base material different from the base material 104 used when the liquid crystal layer 4 is formed. From the viewpoint of handling properties and the like, it is preferable to perform a silane coupling agent treatment on the exposed surface (surface opposite to the substrate) of the liquid crystal layer formed on the substrate. Further, the silane coupling agent treatment is performed on the surface of the liquid crystal layer while the liquid crystal layer 4 is still formed on the base material 104, and the surface on which the organosilicon compound layer is formed is polarized without peeling the liquid crystal layer from the base material. By bonding to the child, process members can be reduced. Furthermore, as shown in FIG. 2, after the polarizing element is formed, the substrate 104 can be used as it is as a protective film for the liquid crystal layer 4.

  The thickness of the organosilicon compound layer 14 obtained using the silane coupling agent is preferably 30 nm or less, more preferably 25 nm or less, and further preferably 20 nm or less. When the film thickness of the organosilicon compound layer is excessively large, the organosilicon compound layer 14 causes cohesive failure when peeling off rework or the like, and the adhesion between the liquid crystal layer 4 and the adhesive layer 12 cannot be kept high. There is. The minimum of the thickness of the organosilicon compound layer 14 is not specifically limited, For example, 1 nm or more, Preferably it is 3 nm or more, More preferably, it is 5 nm or more.

  In general, a liquid crystal layer laminated on a polyvinyl alcohol polarizer through an adhesive layer has low adhesion, and peeling is likely to occur at the adhesive layer interface of the liquid crystal layer. Therefore, in the prior art, as shown in FIG. 4, a transparent protective film 2 such as triacetyl cellulose is bonded to the surface of the polarizer 1 via an adhesive layer 12, and a liquid crystal layer 4 formed in advance thereon. Is being transferred. In contrast, in the present invention, the liquid crystal layer 4 is treated with a silane coupling agent to form an organosilicon compound layer 14 on the surface thereof, and the organosilicon compound layer 14 and the polarizer 1 on the surface of the liquid crystal layer 4. By sticking together through the first adhesive layer 12, the adhesion of the liquid crystal layer can be improved.

  A surface modification layer using a surface modifier such as a silane coupling agent is generally used to improve the adhesion between materials that are not compatible with each other, for example, an inorganic material such as glass and an organic material. . However, until now, there has been no knowledge that the adhesion with a polyvinyl alcohol-based polarizer can be improved by treating the surface of a liquid crystal layer with a silane coupling agent to form an organosilicon compound layer. The present invention has been made on the basis of such new findings, and a polarizing element having excellent adhesion of a liquid crystal layer can be obtained without a transparent protective film between the polarizer and the liquid crystal layer. It is possible to reduce the thickness of the device and to reduce the cost by eliminating the need for a transparent protective film.

[First adhesive layer]
The liquid crystal layer 4 having the surface formed with the organosilicon compound layer 14 by the silane coupling agent treatment is bonded to the polarizer 1 through the first adhesive layer 12. Examples of the adhesive forming the first adhesive layer 12 include acrylic polymers, silicone polymers, polyesters, polyurethanes, polyamides, polyvinyl ethers, vinyl acetate / vinyl chloride copolymers, modified polyolefins, epoxy systems, fluorine systems, and natural materials. A rubber-based polymer such as rubber-based or synthetic rubber-based polymer can be appropriately selected and used. In particular, an aqueous adhesive is preferably used from the viewpoint of enhancing the adhesion between the polarizer and the organosilicon compound layer formed on the surface of the liquid crystal layer. Among them, those mainly composed of polyvinyl alcohol resin are used.

  Examples of the polyvinyl alcohol resin used for the adhesive include a polyvinyl alcohol resin and a polyvinyl alcohol resin having an acetoacetyl group. A polyvinyl alcohol resin having an acetoacetyl group is a polyvinyl alcohol-based adhesive having a highly reactive functional group, and is preferable because durability of the polarizing plate is improved.

  Polyvinyl alcohol resin is polyvinyl alcohol obtained by saponifying polyvinyl acetate; a derivative thereof; a saponified product of a copolymer of vinyl acetate and a monomer having copolymerizability; Examples thereof include modified polyvinyl alcohols that have been converted into ethers, ethers, grafts, or phosphoric esters. Examples of the monomer include unsaturated carboxylic acids such as (anhydrous) maleic acid, fumaric acid, crotonic acid, itaconic acid, (meth) acrylic acid, and esters thereof; α-olefins such as ethylene and propylene, (meth) Examples include allyl sulfonic acid (soda), sulfonic acid soda (monoalkyl malate), disulfonic acid soda alkyl maleate, N-methylol acrylamide, acrylamide alkyl sulfonic acid alkali salt, N-vinyl pyrrolidone, N-vinyl pyrrolidone derivatives, and the like. . These polyvinyl alcohol resins can be used alone or in combination of two or more.

  Moreover, it is preferable that an adhesive agent contains a crosslinking agent. Examples of the crosslinking agent include alkylenediamines having two alkylene groups and two amino groups, such as ethylenediamine, triethylenediamine, and hexamethylenediamine; tolylene diisocyanate, hydrogenated tolylene diisocyanate, trimethylolpropane tolylene diisocyanate adduct, triphenyl Isocyanates such as methane triisocyanate, methylene bis (4-phenylmethane triisocyanate, isophorone diisocyanate and their ketoxime block product or phenol block product; ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerin di or triglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether Epoxies such as diglycidylaniline and diglycidylamine; monoaldehydes such as formaldehyde, acetaldehyde, propionaldehyde and butyraldehyde; glyoxal, malondialdehyde, succinaldehyde, glutardialdehyde, maleindialdehyde, phthaldialdehyde Dialdehydes such as; methylol urea, methylol melamine, alkylated methylol urea, alkylated methylolated melamine, acetoguanamine, condensates of benzoguanamine and formaldehyde, and the like; further sodium, potassium, magnesium, calcium, Examples thereof include salts of divalent metals such as aluminum, iron, nickel, or trivalent metals and oxides thereof, among which amino-formaldehyde Fats and dialdehydes are preferred, amino-formaldehyde resins are preferably compounds having a methylol group, and dialdehydes are preferably glyoxal, particularly methylol melamine, which is a compound having a methylol group. .

  Application | coating of an adhesive agent may be performed to any of a polarizer and a liquid crystal layer (organosilicon compound layer), and may be performed to both. After the bonding, a drying process is performed to form an adhesive layer composed of a coating dry layer. Bonding of the polarizer and the liquid crystal layer can be performed by a roll laminator or the like. Although the thickness in particular of the 1st adhesive bond layer 12 is not restrict | limited, It is preferable that the thickness after drying is about 10-300 nm. From the viewpoint of obtaining a uniform in-plane thickness and obtaining sufficient adhesive strength, the thickness of the first adhesive layer is more preferably 10 to 200 nm, and further preferably 20 to 150 nm. The surface of the organosilicon compound layer 14 formed on the liquid crystal layer 4 and the surface of the polarizer 1 are subjected to surface modification treatment such as hydrophilization for the purpose of improving adhesiveness before attaching an adhesive. May be. Specific examples of the treatment include corona treatment, plasma treatment, primer treatment, and saponification treatment.

[Transparent protective film]
A transparent protective film 3 may be bonded to the surface of the polarizer 1 opposite to the side where the liquid crystal layer 4 is bonded, with a second adhesive layer 13 interposed therebetween as shown in FIG. As a material constituting the transparent protective film, for example, a thermoplastic resin excellent in transparency, mechanical strength, thermal stability, moisture barrier property, isotropy and the like is used. Specific examples of such thermoplastic resins include cellulose resins such as triacetyl cellulose, polyester resins, polyethersulfone resins, polysulfone resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, (meth) acrylic resins, cyclic Examples thereof include polyolefin resins (norbornene resins), polyarylate resins, polystyrene resins, polyvinyl alcohol resins, and mixtures thereof.

  One or more kinds of arbitrary appropriate additives may be contained in the transparent protective film. Examples of the additive include an ultraviolet absorber, an antioxidant, a lubricant, a plasticizer, a mold release agent, a coloring inhibitor, a flame retardant, a nucleating agent, an antistatic agent, a pigment, and a coloring agent.

  Although the thickness of a transparent protective film can be determined suitably, generally it is about 1-500 micrometers from viewpoints of workability | operativity, such as intensity | strength and a handleability, 1-300 micrometers is preferable and 5-200 micrometers is more preferable.

  The material or the like of the second adhesive layer 13 used for bonding the polarizer 1 and the transparent protective film 3 is not particularly limited. For example, the same adhesive as described above with respect to the first adhesive layer is preferably used. be able to. In addition, the 1st adhesive bond layer 12 and the 2nd adhesive bond layer 13 may consist of the same material, and may consist of a different material.

  The bonding between the polarizer 1 and the transparent protective film 3 may be performed either before or after the bonding between the polarizer 1 and the liquid crystal layer 4. Also, the bonding of the polarizer 1 and the transparent protective film 3 and the bonding of the polarizer 1 and the liquid crystal layer 4 can be performed simultaneously.

  The surface of the transparent protective film 3 on which the polarizer 1 is not adhered may be subjected to a hard coat layer, antireflection treatment, sticking prevention, or treatment for diffusion or antiglare. The antireflection layer, the antisticking layer, the diffusion layer, the antiglare layer, and the like can be provided on the transparent protective film itself, or can be provided separately from the transparent protective film as an optical layer.

[Example of laminated structure of polarizing elements]
As shown in FIG. 1, the surface of the liquid crystal layer 4 opposite to the side bonded to the polarizer 1 may be in a state where the liquid crystal layer 4 is exposed without bonding other films or the like. As shown to 2 and 3, the state by which the other film was bonded together may be sufficient. FIG. 2 shows a form in which the base material 104 in forming the liquid crystal layer 4 is in close contact with the liquid crystal layer 4 without being peeled off. In this structure, the base material 104 can be incorporated in a liquid crystal display device or the like as part of the polarizing element. In addition, if the base material 104 is temporarily attached to the surface of the liquid crystal layer 4 until the polarizing element is put into practical use, if the base material 104 is peeled off when used for practical use, a separate separator is provided for surface protection. The surface of the liquid crystal layer 4 can be protected without using the like.

  FIG. 3 shows a form in which the transparent protective film 102 is bonded to the surface of the liquid crystal layer 4 on the opposite side to the polarizer 1 through the adhesive layer 112. In this configuration, the transparent protective film 102 is used for the purpose of protecting the surface of the liquid crystal layer 4 and may have a function as a retardation film, for example. Examples of the adhesive layer 112 for bonding the transparent protective film 102 and the liquid crystal layer include an acrylic polymer, a silicone polymer, polyester, polyurethane, polyamide, polyvinyl ether, vinyl acetate / vinyl chloride copolymer, modified polyolefin, and epoxy. A polymer having a base polymer such as a rubber-based polymer such as a fluorine-based polymer, a fluorine-based rubber, a natural rubber-based polymer, or a synthetic rubber can be appropriately selected and used. A pressure-sensitive adhesive layer can also be used as the adhesive layer 112. The pressure-sensitive adhesive forming such a pressure-sensitive adhesive layer is not particularly limited, but is excellent in optical transparency like an acrylic pressure-sensitive adhesive, and exhibits appropriate wettability, cohesiveness and adhesive pressure-sensitive adhesive properties, weather resistance and Those excellent in heat resistance and the like are preferable.

  Furthermore, the polarizing element of the present invention may be a polarizing element with an adhesive layer in which an adhesive layer is formed on at least one surface. The thickness of the pressure-sensitive adhesive layer can be appropriately determined according to the purpose of use and adhesive force, and is generally 1 to 500 μm, preferably 1 to 50 μm, more preferably 1 to 40 μm, and still more preferably 5 ˜30 μm is preferable, particularly preferably 10 to 25 μm. When the pressure-sensitive adhesive layer is thinner than 1 μm, the durability is deteriorated.

  For the exposed surface of the pressure-sensitive adhesive layer of such a polarizing element with a pressure-sensitive adhesive layer, a separator may be temporarily attached and covered for the purpose of preventing contamination of the pressure-sensitive adhesive layer until it is put to practical use. preferable. Thereby, it can prevent contacting an adhesive layer in the usual handling state. As a separator, for example, a suitable thin leaf body such as a plastic film, rubber sheet, paper, cloth, nonwoven fabric, net, foamed sheet or metal foil, or a laminate thereof, a silicone type, a long mirror alkyl type, or a fluorine type as necessary. An appropriate one according to the prior art, such as those coated with an appropriate release agent such as molybdenum sulfide or molybdenum sulfide, can be used.

[Image display device]
The polarizing element of the present invention can be preferably used for an image display device such as a liquid crystal display device. Such an image display apparatus can have the same configuration as the conventional image display apparatus except that the polarizing element of the present invention is used.

  The liquid crystal display device is manufactured, for example, by appropriately assembling each component such as a liquid crystal cell, an optical member such as the polarizing element of the present invention, and an illumination system (backlight, etc.) as necessary, and incorporating a drive circuit. it can. The configuration of the liquid crystal display device is not particularly limited as long as the polarizing element of the present invention is used on one side or both sides of the liquid crystal cell.

  In general, in order to make the liquid crystal layer 4 act as optical compensation, it is incorporated in the liquid crystal display device so that the liquid crystal layer 4 side of the polarizing element 20 faces the liquid crystal cell, but the surface opposite to the liquid crystal layer 4 (see FIG. 1 may be incorporated so that the surface on the transparent protective film 3 side in 1 faces the liquid crystal cell. For example, in the case where the liquid crystal layer 4 is a layer having a different alignment state for each minute region, a polarizing element that is disposed on the viewing side with respect to the liquid crystal cell is disposed such that the liquid crystal layer 4 is on the viewing side with respect to the polarizer 1. Accordingly, the present invention can be applied to a space-division type three-dimensional display in which a right-eye image and a left-eye image appear for each pixel.

  The image display device such as the liquid crystal display device is used for any appropriate application. Applications include, for example, OA equipment such as desktop personal computers, notebook personal computers, and copiers, mobile phones, watches, digital cameras, personal digital assistants (PDAs), portable devices such as portable game machines, video cameras, televisions, microwave ovens, etc. Household electrical equipment, back monitor, car navigation system monitor, car audio and other in-vehicle equipment, display equipment for commercial store information monitors, security equipment such as monitoring monitors, nursing care monitors, medical monitors, etc. Nursing care / medical equipment.

  The present invention will be further described below with reference to examples and comparative examples, but the present invention is not limited to these examples.

[Example 1]
(Preparation of liquid crystal layer)
A polymerizable liquid crystal compound (manufactured by BSAF, trade name “Palicolor LC242”) was dissolved in cyclopentanone to prepare a solution having a solid content of 30% by weight. To this solution, a fluorosurfactant (trade name “Megafac RS-714” manufactured by DIC) and a polymerization initiator (trade name “Irgacure 369” manufactured by Ciba Geigy) were added to prepare a coating solution. The addition amounts of the surfactant and the polymerization initiator were 0.01 parts by weight and 3 parts by weight, respectively, with respect to 100 parts by weight of the liquid crystal compound.

  A polyethylene terephthalate film (trade name “Lumirror RC06” manufactured by Toray Industries, Inc., thickness 75 μm) was rubbed with a rayon rubbing cloth to obtain an alignment substrate. The coating solution was uniformly applied to the rubbing-treated surface of this alignment substrate using a wire bar (coating wet thickness: about 1.5 μm) to form a coating layer.

Thus, the said coating layer formed on the base material was dried for 2 minutes with 90 degreeC air circulation type thermostat oven with the orientation base material, and the solidified layer in which the liquid crystalline compound inclined-aligned was formed. The surface of the obtained solidified layer is irradiated with ultraviolet rays in an air atmosphere at room temperature (25 ° C.) so that the integrated irradiation light quantity at a wavelength of 365 nm is 300 mJ / cm ² using a conveyor type ultraviolet irradiation device. A liquid crystal layer in which the tilted orientation of the functional compound was fixed was formed.

(Silane coupling agent treatment)
A silane coupling agent solution was prepared by diluting 20 parts by weight of a silane coupling agent (trade name “APZ-6661” manufactured by Toray Dow Corning) with 80 parts by weight of isopropyl alcohol. After corona-treating the surface of the liquid crystal layer, the silane coupling agent solution is applied using a wire bar and dried in an air-circulating constant temperature oven at 80 ° C. for 2 minutes to form an organosilicon compound layer on the surface of the liquid crystal layer. Formed.

(Production of polarizer)
A polyvinyl alcohol film having a polymerization degree of 2400, a saponification degree of 99.9%, and a thickness of 75 μm is freely immersed so as to swell and swell in 30 ° C. warm water so that the length of the polyvinyl alcohol film becomes twice the original length. End uniaxial stretching was performed. Next, the mixture is immersed in an aqueous solution (dyeing bath) having a concentration of a mixture of iodine and potassium iodide (weight ratio 1:16) of 0.3% by weight so that the polyvinyl alcohol film length becomes three times the original length. The film was dyed while uniaxially stretching at the free end. Thereafter, the film was stretched so that the length of the polyvinyl alcohol film was 4 times the original length while immersed in an aqueous solution (crosslinking bath 1) of 3% by weight of boric acid and 3% by weight of potassium iodide. In an aqueous solution of 4% by weight boric acid and 5% by weight potassium iodide (crosslinking bath 2), the polyvinyl alcohol film was stretched so that its length was 6 times the original length. Thereafter, iodine ion impregnation treatment was performed with an aqueous solution (iodine impregnation bath) of 3% by weight of potassium iodide, and then dried in an oven at 60 ° C. for 4 minutes to obtain a polarizer. The thickness of the obtained polarizer was 28 μm.

(Preparation of adhesive)
A polyvinyl alcohol resin containing an acetoacetyl group (average polymerization degree 1200, saponification degree 98.5 mol%, acetoacetylation degree 5 mol%) 100 parts by weight, methylol melamine 32 parts by weight, 30 ° C. temperature condition Below, the adhesive aqueous solution was prepared so that it might melt | dissolve in a pure water and solid content concentration might be 3.2 weight%.

(Preparation of polarizing element)
Using the above-mentioned adhesive, a liquid crystal layer on one side of the polarizer and a 80 μm thick triacetyl cellulose film as a transparent protective film on the other side under the temperature condition of 30 ° C. (trade name “Fujitac, manufactured by Fuji Film Co., Ltd.) TD80UL ") was bonded with a roll bonding machine, and then dried at 60 ° C for 4 minutes. After drying, the substrate film was peeled off from the liquid crystal layer to obtain a polarizing element having a laminated structure as shown in FIG. When the cross section of the obtained polarizer was observed with a transmission electron microscope (TEM), the thickness of the organosilicon compound layer was 25 nm.

[Comparative Example 1]
After the liquid crystal layer was formed in the same manner as in Example 1, the surface of the liquid crystal layer was not subjected to silane coupling treatment, and only corona treatment was performed. Using this liquid crystal layer, in the same manner as in Example 1, a liquid crystal layer was bonded to one surface of a polarizer and a transparent protective film was bonded to the other surface to obtain a polarizing element.

[Comparative Example 2]
As in Comparative Example 1, the surface of the liquid crystal layer was not subjected to silane coupling treatment, and plasma irradiation treatment was performed instead of corona treatment. Using this liquid crystal layer, a polarizing element was obtained by laminating a liquid crystal layer on one surface of a polarizer and a transparent protective film on the other surface.

[Comparative Example 3]
As in Comparative Example 1, the surface of the liquid crystal layer was not subjected to silane coupling treatment, and saponification treatment was performed instead of corona treatment. Using this liquid crystal layer, a polarizing element was obtained by laminating a liquid crystal layer on one surface of a polarizer and a transparent protective film on the other surface.

[Comparative Example 4]
After forming the liquid crystal layer in the same manner as in Example 1, the surface of the liquid crystal layer was subjected to corona treatment to form a urethane-based primer layer. Using this liquid crystal layer, a polarizing element was obtained by laminating a liquid crystal layer on one surface of a polarizer and a transparent protective film on the other surface.

[Reference Example 1]
In Example 1, instead of laminating the liquid crystal layer on one side of the polarizer, a transparent protective film was laminated on both sides of the polarizer to obtain a polarizing plate in which the transparent protective film was laminated on both sides of the polarizer. .

[Reference Example 2]
In the silane coupling agent treatment of Example 1, the coating thickness of the silane coupling agent was increased. Other than that was carried out similarly to Example 1, and obtained the polarizing element which has a laminated structure as shown in FIG. When the cross section of the obtained polarizer was observed with a transmission electron microscope (TEM), the thickness of the organosilicon compound layer was 40 nm.

[Evaluation]
A blade of a cutter knife is inserted between the polarizer on the side surface of the polarizing element obtained in Examples, Comparative Examples and Reference Examples and the transparent protective film, and the polarizer and the transparent protective film are attached at the end of the polarizing element. It peeled. At the peeling part, each of the polarizer and the transparent protective film was grasped and peeled by pulling in the opposite direction.

  In the polarizing element of Comparative Examples 1-4, it peeled completely between a polarizer and a liquid crystal layer, and the adhesiveness of a polarizer and a liquid crystal layer was scarce. On the other hand, in the polarizing element of Example 1, the polarizer and / or the transparent protective film was broken and could not be peeled off. Also in the polarizing plate of Reference Example 1, the polarizer and / or the transparent protective film was broken and could not be peeled off.

  This shows that the polarizing element of Example 1 has higher adhesion between the polarizer and the liquid crystal layer than the polarizing element of the comparative example. On the other hand, in the polarizing element of Reference Example 2, cohesive failure occurred in the organosilicon compound layer, and the film was completely peeled between the polarizer and the liquid crystal layer.

DESCRIPTION OF SYMBOLS 1 Polarizer 2,3 Transparent protective film 102 Transparent protective film 4 Liquid crystal layer 5 Adhesive layer 12,13 Adhesive layer 112 Adhesive layer 14 Organosilicon compound layer 20 Polarizing element 104 Base material

Claims (5)

A polarizing element comprising a liquid crystal layer in which the orientation of a liquid crystalline compound is fixed on a polyvinyl alcohol film polarizer,
The liquid crystal layer contains a liquid crystal compound and a surfactant,
An organic silicon compound layer having a silane coupling agent is formed on the surface of the polarizer side of the liquid crystal layer having a hydrophilic surface,
The organosilicon compound layer has a thickness of 25 nm or less,
The polarizing element by which the said polarizer and the organosilicon compound layer of the liquid-crystal layer surface are bonded together through the 1st adhesive bond layer.   The polarizing element according to claim 1, wherein a transparent protective film is bonded to the other surface of the polarizer via a second adhesive layer.   The polarizing element according to claim 1, wherein the surfactant contained in the liquid crystal layer is a silicone-based surfactant.   The polarizing element according to claim 1, wherein the surfactant contained in the liquid crystal layer is a fluorine-based surfactant. A method for producing the polarizing element according to claim 1,
A step of preparing a liquid crystal layer containing a liquid crystal compound and a surfactant and in which the alignment of the liquid crystal compound is fixed;
A step of forming an organosilicon compound layer by treating the surface of the liquid crystal layer with a silane coupling agent solution; and the liquid crystal layer on one surface of the polyvinyl alcohol film polarizer via a first adhesive layer Bonding the organosilicon compound layer forming surface of
The manufacturing method of a polarizing element which has these.