JP2010256895A - Method of manufacturing polarizing element, and polarizing element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide: a polarizing element of a deep color with a transmittance of 20% or less without in-plane distribution of polarization degrees; and a method of manufacturing the polarizing element to efficiently manufacture the polarizing element with simple steps. <P>SOLUTION: The method of manufacturing the polarizing element includes: a process I to form an alignment film 4 by applying alignment coat liquid containing at least alkoxy silane and/or hexalkoxy disiloxane on a substrate 1 dyed to have a luminous transmittance above 75%; a process II to form an alignment layer 5 having monoaxial polishing traces by polishing the alignment film in a monoaxial direction; a process III to form a polarizing layer 6 by aligning and depositing dichromatic dye on the alignment layer; and a process IV to form a protection layer 7 for fixing dye on the polarizing layer. The polarizing element is obtained by the method. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a polarizing element. More specifically, the present invention relates to a dark polarizing element having no in-plane distribution of the degree of polarization and a method for manufacturing the same.

A technique for producing a polarizing lens by introducing and fixing a polarizing film (a film obtained by stretching polyvinyl alcohol (PVA) dyed with an iodine compound or a dichroic dye in a uniaxial direction) into a lens substrate is known ( For example, see Patent Documents 1 and 2).
However, since the polarizing film has in-plane anisotropy due to the uniaxial stretching process in the thermal expansion / contraction behavior, the lens substrate produced after the heating process for producing the polarizing lens An internal strain having anisotropy occurs. This internal strain causes refractive index anisotropy in the lens substrate having an isotropic refractive index by a so-called photoelastic effect.
As a result, when the polarized light is incident on the lens, the polarized light is slightly rotated according to the anisotropic internal distortion, so that a portion having a low degree of polarization is generated in the plane.

Observing polarized light incident in such a state where the degree of polarization is non-uniform causes light and darkness in the lens surface, which impedes the function of the polarizing lens. This light and darkness is often observed in the form of a cross that is parallel to and orthogonal to the absorption axis direction of the polarizing lens, and the suppression of the light and darkness of the in-plane distribution of the internal distortion and the resulting polarization degree is a condition for manufacturing the lens substrate. Improvements have been promoted through adjustment of the above, but it has not been solved sufficiently.
In particular, in the case of a lens having a high density, that is, a low transmittance, the influence of this effect is noticeable. This is because it is considered that human beings can easily detect a slight change in transmitted light amount when the density is high (transmittance is low).

In addition, a method for manufacturing a polarizing element using a dye having dichroism and exhibiting a liquid crystal phase in an aqueous solution state is known. For example, a polarizing element having a polarizing layer and a protective layer on the surface of a transparent substrate, and having an inorganic intermediate layer as an alignment film between the transparent substrate and the polarizing layer has been proposed (for example, Patent Document 3). reference). The inorganic intermediate layer is made of a combination of silicon oxide, metal oxide, or a mixture of these, and a vapor-deposited film of these metal oxides is formed as an array film on the surface of the substrate by vacuum vapor deposition. A layer is formed.
Such a polarizing element, unlike a polarizing element using a polarizing film, suppresses the occurrence of internal distortion and in-plane distribution of the degree of polarization resulting therefrom.
However, a method for adjusting the transmission color of the polarizing element has not been developed yet. For example, as a method for adjusting the transmission color, a method of adjusting the transmittance according to the amount of dichroic dye used can be considered, but it is difficult to deposit and fix the dye to be used on a substrate thicker than a certain amount. However, a dark color with a transmittance of about 20% has not been realized.

Japanese Patent Laid-Open No. 2005-99687 JP 2007-52210 A Special table 2008-527401

  The present invention has been made under such circumstances, and is a dark-colored polarizing element having a transmittance of 20% or less without in-plane distribution of the degree of polarization, and efficiently manufacturing the polarizing element by a simple process. An object of the present invention is to provide a method of manufacturing a polarizing element that can be used.

  As a result of intensive studies to achieve the above object, the present inventors have used a substrate dyed to have a luminous transmittance of 75% or less, and alkoxysilane and / or hexaalkoxy disilane on the substrate. It has been found that the above problem can be solved by forming an alignment layer using an alignment film coating solution containing siloxane. The present invention has been completed based on such findings.

That is, the present invention relates to a method for manufacturing a polarizing element having the following steps I to IV and a polarizing element obtained by the manufacturing method.
Step I: Using a base material dyed with a luminous transmittance of 75% or less, an alkoxysilane represented by the following general formula (1) and / or a hexagon represented by the following general formula (2) on the base material Step of depositing an alignment film containing at least an alkoxydisiloxane (A) to form an alignment film Si (OR ¹ ) _a (R ² ) _4-a (1)
_{^{(R 3 O) 3 Si-}} O-Si (OR 4) 3 (2)
(Wherein R ¹ , R ³ and R ⁴ are each independently an alkyl group having 1 to 5 carbon atoms, R ² is an alkyl group having 1 to 10 carbon atoms, and a is 3 or 4. .)
Step II: A step of polishing the alignment film formed in Step I in a uniaxial direction to form an alignment layer having polishing marks in a uniaxial direction Step III: A dichroic dye on the alignment layer formed in Step II Forming a polarizing layer by arranging and depositing layers Step IV: forming a protective layer for fixing a dye on the polarizing layer formed in Step III

  According to the present invention, there are provided a dark-colored polarizing element having no in-plane distribution of polarization degree and a transmittance of 20% or less, and a polarizing element manufacturing method capable of efficiently manufacturing the polarizing element in a simple process. can do.

It is a cross-sectional schematic diagram which shows an example of the manufacturing process of the polarizing element of this invention.

Hereinafter, the present invention will be described in detail.
The structure of the polarizing element obtained in the present invention will be described with reference to FIG. The polarizing element in the present invention has an alignment layer 5 and a polarizing layer 6 on a substrate 1. The polarizing layer 6 is formed by depositing and arranging dichroic dyes, and usually has a protective layer 7 for fixing the dyes thereon. Furthermore, the polarizing element in the present invention has a function such as a water repellent film on the hard coat layer 2, the adhesion layer 3, or the protective layer 7 on the substrate 1 as in the example of FIG. May have a conductive film 8. As a suitable example of a polarizing element, the polarizing lens which uses a lens base material as the base material 1 is mentioned, for example.

The manufacturing method of the polarizing element in this invention has the following process I-process IV.
Step I: Using a base material dyed with a luminous transmittance of 75% or less, an alkoxysilane represented by the following general formula (1) and / or a hexagon represented by the following general formula (2) on the base material Step of depositing an alignment film containing at least an alkoxydisiloxane (A) to form an alignment film Si (OR ¹ ) _a (R ² ) _4-a (1)
_{^{(R 3 O) 3 Si-}} O-Si (OR 4) 3 (2)
(Wherein R ¹ , R ³ and R ⁴ are each independently an alkyl group having 1 to 5 carbon atoms, R ² is an alkyl group having 1 to 10 carbon atoms, and a is 3 or 4. .)
Step II: A step of polishing the alignment film formed in Step I in a uniaxial direction to form an alignment layer having polishing marks in a uniaxial direction Step III: A dichroic dye on the alignment layer formed in Step II Forming a polarizing layer by arranging and depositing layers Step IV: forming a protective layer for fixing a dye on the polarizing layer formed in Step III

  In step I, the substrate 1 dyed with a luminous transmittance of 75% or less is used to form an array film 4 on the substrate (see FIG. 1A).

(Base material)
The base material used in the present invention is a base material dyed with a luminous transmittance of 75% or less. When using a base material with a luminous transmittance of more than 75%, Dye in a predetermined color. The luminous transmittance is preferably 60% or less, more preferably 55% or less, and even more preferably 50% or less, from the viewpoint of sufficiently exerting the effects of the present invention.
As the dyeing method of the base material, a conventionally known method applicable to the lens base material to be dyed can be employed. For example, a sublimation dyeing method, a method of warm immersion in a dye solution, a dye or the like on the lens base material Examples thereof include a method in which a colorant is mixed, a method in which a colored film is attached to a lens, and the color is transferred to the lens surface by heating or the like. A desired color tone and transmittance can be obtained by further providing a polarizing layer comprising a dichroic dye on the substrate.
The final color tone and transmittance of the polarizing element are determined by this substrate dyeing density and the amount of dichroic dye used in the polarizing layer. For this reason, the color tone and dyeing density at the time of substrate dyeing can be determined in consideration of the color tone and transmittance of the polarizing layer.

Although it does not specifically limit as a material of a base material, A plastic base material, an inorganic glass base material, etc. are mentioned. The material of the plastic substrate is, for example, methyl methacrylate homopolymer, copolymer of methyl methacrylate and one or more other monomers, diethylene glycol bisallyl carbonate homopolymer, diethylene glycol bisallyl carbonate and one or more other Copolymers with monomers, sulfur-containing copolymers, halogen copolymers, polycarbonate, polystyrene, polyvinyl chloride, unsaturated polyester, polyethylene terephthalate, polyurethane, polythiourethane, and polymers having epithio groups Etc.
Although the surface shape of a base material is not specifically limited, It can be set as arbitrary shapes, such as planar shape, concave shape, or convex shape.

  In the present invention, the alignment film formed on the substrate is preferably an alignment film formed by a sol-gel method from the viewpoint of not requiring a large facility and simplifying the process.

In the sol-gel method, an alignment film (sol-gel film) is formed by attaching an alignment film coating solution onto a substrate.
The alignment film coating solution preferably contains at least an alkoxysilane represented by the following general formula (1) and / or a hexaalkoxydisiloxane (A) represented by the following general formula (2). The component (A) is used for the hydrolysis reaction to proceed in the presence of water to form a continuous skeleton structure in the film, to impart film curability, and to further suppress the peeling of the polarizing layer. The
The alignment film coating solution can be prepared by mixing other components such as an inorganic oxide sol, a solvent, and a curing catalyst as necessary.

Si (OR ¹ ) _a (R ² ) _4-a (1)
(R ³ O) ₃ Si—O—Si (OR ⁴ ) ₃ (2)

Here, R ¹ in the general formula (1) and R ^{3 to} R ⁴ in the general formula (2) are each independently an alkyl group having 1 to 5 carbon atoms, and are linear, branched, or cyclic. For example, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, pentyl group, cyclopentyl group and the like can be mentioned. It is done. Among these, a methyl group and an ethyl group are preferable.
R < ² > in the said General formula (1) is a C1-C10 alkyl group, The C1-C5 alkyl group, hexyl group, heptyl group, octyl group, and 2-ethylhexyl group which were illustrated above. Etc. In this, a methyl group, an ethyl group, a propyl group, and a butyl group are preferable. A in the general formula (1) is 3 or 4.

  Examples of the tetraalkoxysilane represented by the general formula (1) (wherein a = 4) include tetraethoxysilane (TEOS), tetramethoxysilane, tetraisopropoxysilane, tetra-n-propoxysilane, and tetra-n. -Butoxysilane tetra-sec-butoxysilane, tetra-tert-butoxysilane and the like.

  Examples of trialkoxysilanes represented by the general formula (1) (wherein a = 3) include, for example, methyltrimethoxysilane, methyltriethoxysilane, methyltriisopropoxysilane, methyltri-n-propoxysilane, and methyltri-n. -Butoxysilane, methyltri-sec-butoxysilane, methyltri-tert-butoxysilane and the like.

  The hexaalkoxydisiloxane represented by the general formula (2) is not particularly limited, and examples thereof include hexamethoxydisiloxane and hexaethoxydisiloxane.

  Among these, tetraethoxysilane, tetramethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, tetraisopropoxysilane, methyltriisopropoxysilane, hexaethoxydisiloxane, and hexamethoxydisiloxane, and more Tetraethoxysilane, tetramethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, and more preferably tetraethoxysilane. These can be used singly or in combination of two or more.

In the present invention, as an alkoxysilane compound other than the component (A), for example, a functional group-containing alkoxysilane can be used in combination with the component (A) as long as the effects of the present invention are not impaired. From the viewpoint of reducing peeling of the polarizing layer in the process, it is preferably not contained. Specific examples of the functional group-containing alkoxysilane include glycidoxy group-containing trialkoxysilanes, epoxyalkylalkoxysilanes, amino group-containing alkoxysilanes, and the like exemplified later as materials used for the protective layer.
In the present invention, it is preferable to use a tetraalkoxysilane represented by the general formula (1) (wherein a = 4) alone or more than other silane compounds among the silane compounds.

Examples of the alignment film coating liquid used in the present invention include a mixture containing the above component (A) and an inorganic oxide sol. Among them, from the viewpoint of suppressing the peeling of the polarizing layer, the above (A) Preferred examples include a component, a mixture containing water (B) and alcohols (C).
The method for preparing the alignment film coating solution is not particularly limited, and can be carried out by weighing out a predetermined amount of each component and sufficiently stirring and mixing them. In addition, the addition order of each component is not specifically limited.

When the inorganic oxide sol is used, the inorganic oxide is selected from Mg, Ca, Sr, Ba, Al, In, Ge, Bi, Fe, Cu, Y, Zr, Ni, Ta, Si, Ti, and the like. And oxides composed of one or more elements. Among these, from the viewpoint of increasing the hardness of the alignment layer, further suppressing peeling of the polarizing layer, and ease of production, SiO ₂ , TiO ₂ , ZrO ₂ , CeO ₂ , ZnO, SnO ₂ and indium tin oxide (ITO) is preferred. Of these, silica (SiO ₂ ) is preferably used from the viewpoint of achieving both chemical stability and film hardness increasing effect. Inorganic oxides can be used singly or in combination of two or more.

The inorganic oxide sol is obtained by dispersing inorganic oxide particles in a solvent such as alcohol so that the solid content is preferably 0.5 to 70% by mass. Further, from the viewpoint of increasing the film hardness and not causing haze (cloudiness) of the film itself, the particle diameter of the inorganic oxide particles is preferably 1 to 100 nm.
As the molar ratio of the component (A) to the solid content in the inorganic oxide sol [(A) / inorganic oxide sol (solid content)], the alignment layer does not become excessively hard and is laminated on the alignment layer. From the viewpoint of improving the adhesion to the polarizing layer, it is preferably 99.9 / 0.1 to 40/60, more preferably 90/10 to 45/55, still more preferably 80/20 to 50 /. 50, particularly preferably 75/25 to 60/40.

When preparing the alignment film coating solution as a mixture containing the components (A) to (C), the amount of water (B) added to the system is 0.5 to 3 with respect to the component (A). The range of molar equivalent is preferable, and the range of 1-2 molar equivalent is more preferable. If the amount of water added is 0.5 molar equivalent or more with respect to component (A), a film having a hardness that can withstand the use of a plastic lens can be formed without any alkoxy groups remaining during the hydrolysis reaction. If it is 3 molar equivalents or less, film curing due to polymerization of (A) components occurs more than necessary, and one molecule of polysiloxane formed by curing becomes larger, resulting in a rough film structure. As a result, there is no concern that sufficient hardness as a film for plastic lenses cannot be obtained.
There is no restriction | limiting in particular as the addition method of water (B), In order to accelerate | stimulate a hydrolysis reaction, you may add as the aqueous solution of the acid or alkali catalyst normally added.

The alcohol (C) is used as a solvent soluble in alkoxysilane and / or hexaalkoxydisiloxane (A) and water (B).
Examples of alcohols (C) include methanol, ethanol, isopropanol, butanol, 2-methoxyethanol, diacetone alcohol, and 1-methoxy-2-propanol. Among these, methanol, ethanol, and isopropanol are preferable from the viewpoint of the solubility of silanes and siloxanes in alcohols.
The usage-amount of alcohol (C) becomes like this. Preferably it is the range of 20-500 mass% with respect to (A) component, More preferably, it is the range of 50-400 mass%. If the amount of the alcohol (C) used is 20% by mass or more with respect to the component (A), sufficient force to dissolve the component (A) can be secured, and if it is 500% by mass or less, (A) It is possible to keep the reactivity of the components.
As long as the effect of the present invention is not impaired, amides such as dimethylformamide, glycol ethers such as propylene glycol monomethyl ether, and the like can be used as desired as the solvent.

Next, the mixture prepared above, preferably a mixture containing the components (A) to (C), is subjected to heat treatment, subjected to hydrolysis and polycondensation of alkoxy groups in the alkoxysilane material by a sol-gel method. A film coating solution can be prepared.
The temperature for the heat treatment is preferably in the range of 40 to 120 ° C., more preferably in the range of 50 to 110 ° C., from the viewpoint of sufficiently allowing the hydrolysis reaction to proceed within the range in which precipitation or gelation of the component (A) does not occur. The range of 70-100 degreeC is further more preferable.
Further, from the viewpoint of obtaining a sufficient reaction rate, it is preferable to perform heat treatment with stirring while maintaining as high a temperature as possible. For this purpose, in the heat treatment, the mixture containing the components (A) to (C) is heated to reflux. It is preferable to do.
The heat treatment time is preferably in the range of 0.5 to 24 hours. Moreover, it is preferable that the temperature is controlled so as to be continuously maintained within a range of the heating temperature. If kept at a high temperature for a long time, problems such as precipitation and gelation of component (A) occur. From these viewpoints, the range of 1 to 15 hours is more preferable.
By using the alignment film coating solution prepared as described above, it becomes possible to improve the adhesion between the alignment layer and the polarizing layer formed in a later step, and effectively reduce the peeling of the polarizing layer. Can do.

Furthermore, in order to reduce peeling and fogging of the polarizing layer, it is preferable to add an aluminum chelate (D) to the mixture obtained above and further heat-treat as necessary. Examples of the aluminum chelate (D) include aluminum acetylacetonate, ethyl acetoacetate aluminum diisopropylate, aluminum tris (ethyl acetoacetate), alkyl acetoacetate aluminum diisopropylate, aluminum monoacetylacetonate bis (ethyl acetoacetate) , Aluminum tris (acetylacetonate), and aluminum monoisopropoxymonooleoxyethyl acetoacetate. These can be used singly or in combination of two or more.
The amount of the aluminum chelate (D) used is preferably in the range of 0.05 to 5% by mass, more preferably in the range of 0.1 to 3% by mass with respect to the component (A). If the amount of the aluminum chelate (D) used is 0.05% by mass or more with respect to the component (A), the effect of reducing peeling and fogging can be imparted, and if it is 5% by mass or less, aluminum is used. There is no problem of decrease in adhesion and transparency due to excessive content.
(D) As temperature of the heat processing after component addition, Preferably it is the range of 40-120 degreeC, More preferably, it is the range of 50-100 degreeC. (D) As time of heat processing after component addition, Preferably it is the range of 0.5 to 24 hours. The heat treatment is preferably performed with stirring.
The amount of the solid component of the array film coating solution is preferably 0.2 to 20% by mass, more preferably 1 to 10% by mass. The amount of the solid component of the coating liquid can be adjusted using a solvent such as the alcohols exemplified above so as to be in a desired range. In addition, the solid component of a coating liquid can be calculated by the method as described in the Example mentioned later.

In step I, the alignment film coating solution prepared above is adhered onto the substrate to form an alignment film (see FIG. 1A). According to such a film forming method, compared with a method using a large-scale vacuum vapor deposition equipment necessary for forming a layer made of an inorganic oxide such as SiO ₂ , the complexity is eliminated, and the manufacturing process is reduced. It can be simplified.

  In the polarizing element of the present invention, an alignment layer is formed on a substrate. The alignment layer may be directly laminated on the substrate, and may have a hard coat layer or a primer layer between the substrate and the alignment layer.

The hard coat layer formed as necessary between the substrate and the alignment layer is not particularly limited, and a coating composition comprising a known organosilicon compound and inorganic oxide colloidal particles can be used. Examples of the organosilicon compound and the inorganic oxide colloidal particles include those described in paragraphs [0071] to [0074] of JP-A-2007-77327. The coating composition for the hard coat layer can be prepared by a conventionally known method.
Examples of the method for forming the hard coat layer on the substrate include a method of applying the coating composition to the substrate. As a coating means, a commonly performed method such as a dipping method, a spin coating method, or a spray method can be applied, but a dipping method or a spin coating method is particularly preferable from the viewpoint of surface accuracy.
Moreover, well-known various resins, such as a polyurethane, can be used for a primer layer from a viewpoint of improving adhesiveness.

  Before depositing the coating liquid on the substrate, the substrate is subjected to chemical treatment with acid, alkali, various organic solvents, physical treatment with plasma, ultraviolet rays, detergent treatment using various detergents, sandblast treatment, By performing primer treatment using various resins, it is possible to improve the adhesion between the substrate and the alignment layer.

The coating liquid is applied onto a substrate and subsequently heat-treated to adhere to the substrate, and preferably a sol-gel film can be formed. The coating method for the coating liquid is not particularly limited, and known methods such as spin coating, dip coating, flow coating, spray coating, and the like can be applied. Among these, spin coating is preferable from the viewpoint of surface accuracy.
The thickness of the sol-gel film is preferably 0.02 to 5 μm, more preferably 0.05 to 0.5 μm. When the thickness is 0.02 μm or more, the entire film can be made to function without being peeled off during polishing, and when it is 5 μm or less, the occurrence of cracks can be reduced.
The conditions for coating and heat treatment are not particularly limited, but for example, the coating conditions are preferably in the range of 0.5 to 3 minutes. The rotation speed of the spin coater in the case of spin coating is preferably in the range of 200 to 2000 rpm. Moreover, it is preferable to perform heat processing at 50-120 degreeC and 0.5 to 3 hours.

It is preferable that after the step I and before the next step II, the alignment film formed in the step I is dipped in an aqueous solution of weak acid or weak alkali. By immersing the array film in a weak acid or weak alkali solution, the adhesion between the array film and the dye layer is increased and the film is hardly peeled off, the scratch resistance is further improved, and the occurrence of haze due to polishing scratches can be suppressed. Herein, the term dissociation constant pK _a from the weak acid points to 3.5 or more acid dissociation exponent pK _b is a weak alkaline refers to a 3.5 or more alkaline.
Examples of the weak acid or weak alkali used for the dipping treatment include weak acids such as acetic acid, oxalic acid, formic acid, and benzoic acid, and weak alkalis such as aqueous ammonia, monoethanolamine, diethanolamine, and triethanolamine. The immersion conditions are not particularly limited, but are preferably 1 to 30 minutes, more preferably 3 to 20 minutes.

In Step II, in order to deposit the dichroic dyes on the alignment layer, the alignment film 4 formed in Step I is polished in a uniaxial direction to form an alignment layer 5 having polishing marks in the uniaxial direction. (See FIG. 1B). The polishing treatment is preferably performed using an abrasive.
In step II, the alignment layer formed on the substrate is provided for aligning and depositing the dichroic dye. The alignment layer is formed by attaching an alignment film coating solution, and is preferably a sol-gel film.
Here, in the case of liquid crystal, it is known that the liquid crystal is arranged in a certain directional relationship with this direction by unidirectional friction processing or polishing processing on the substrate. For example, in manufacturing a liquid crystal display (LCD), it is well known that a so-called rubbing process is performed in which an alignment film (such as polyimide) attached on a substrate is rubbed in one direction in order to align liquid crystals in a cell. . Techniques for coating a dichroic dye solution on a unidirectionally polished substrate, arranging the dye and utilizing the dichroism are disclosed in, for example, US Pat. No. 2,400,087 and US Pat. No. 4,865,668. Is disclosed.
Also in the present invention, the dichroic dyes can be aligned in the uniaxial direction by polishing the sol-gel film formed on the substrate, as in the case of liquid crystals in liquid crystal display (LCD) production.

The abrasive used for the polishing treatment is not particularly limited, and for example, a slurry in which a slurry containing abrasive particles is immersed in a foam material such as urethane foam can be used. Examples of the abrasive particles include Al ₂ O ₃ , ZrO ₂ , TiO ₂ , and CeO ₂ . Among these, Al ₂ O ₃ is preferable from the viewpoints of hardness (easiness of polishing, finishing) for the formed sol-gel film and chemical stability. These may be used alone or in combination of two or more. Moreover, the slurry containing abrasive particles may contain a viscosity modifier, a pH adjuster and the like.

The average particle size of the abrasive particles is preferably 3 μm or less. Further, in the case of a sol-gel film, since there is no hardness like a thin film made of an inorganic substance, polishing using an abrasive having an average particle size of less than 2 μm is possible. -1.5 micrometers is more preferable, and 0.7-1.4 micrometers is still more preferable. In addition, the use of finer particle abrasive than conventional ones enables finer polishing, resulting in higher haze pressure and haze generation due to polishing scratches even when intensive polishing is performed at one location. It is possible to suppress the generation of defective products, and the polarizing element can be easily manufactured.
The polishing conditions are not particularly limited, and the rotation speed, polishing pressure, polishing time, and the like can be adjusted as appropriate.

In step III, a dichroic dye is arranged and deposited on the alignment layer 5 having uniaxial polishing marks formed in step II to form the polarizing layer 6 (see FIG. 1C).
The polarizing layer in the present invention comprises one or more dichroic dyes. Here, “dichroism” means a property in which the color of transmitted light varies depending on the propagation direction because the medium has selective absorption anisotropy with respect to light, and the dichroic dye is polarized light. On the other hand, the light absorption is strong in a specific direction of the dye molecule, and the light absorption is small in the direction perpendicular to the dye molecule. Among dichroic dyes, those that exhibit a liquid crystal state in a certain concentration and temperature range when water is used as a solvent are known. Such a liquid crystal state is called lyotropic liquid crystal. If the dye molecules can be arranged in a specific direction using the liquid crystal state of the dichroic dye, the element can have anisotropy of light absorption and can function as a polarizing element.
As a dichroic dye used for this invention, it does not specifically limit, What is known as what is normally used for a polarizing element can be used. Examples include azo, anthraquinone, merocyanine, styryl, azomethine, quinone, quinophthalone, perylene, indigo, tetrazine, stilbene, benzidine and the like. Moreover, the thing etc. which are described in US Patent 24000877 specification and Japanese translations of PCT publication No. 2002-527786 are mentioned.

Usually, before forming the polarizing layer, the polished surface of the array layer is completely washed and dried. Next, a polarizing layer is formed by applying an aqueous solution or suspension (preferably an aqueous solution) containing a dichroic dye on an array layer having polishing marks, and further performing a water-insoluble treatment of the dichroic dye. can do.
A polarizing element having a desired hue can be produced by blending a dye other than the above with an aqueous solution or suspension containing a dichroic dye as long as the effects of the present invention are not impaired. Furthermore, additives such as a rheology modifier, an adhesion promoter, a plasticizer, and a leveling agent may be blended as necessary from the viewpoint of improving applicability and the like.
The application method is not particularly limited, and examples thereof include known methods such as spin coating, dip coating, flow coating, and spray coating.
As the water insolubilization treatment, a method of immersing the dichroic dye applied on the alignment layer in an aqueous metal salt solution is preferable. The metal salt that can be used is not particularly limited, and examples include AlCl ₃ , BaCl ₂ , CdCl ₂ , ZnCl ₂ , FeCl _2, and SnCl ₂ . Among these, AlCl ₃ and ZnCl ₂ are preferable from the viewpoint of safety. After the water-insoluble treatment, the surface of the dichroic dye may be further dried.
Although the thickness of a polarizing layer is not specifically limited, It is preferable in it being the range of 0.05-0.5 micrometer.

Step IV is a step of forming a protective layer 7 for fixing a dye on the polarizing layer 6 formed in Step III (see FIG. 1D).
As a material used for the protective layer, an organic silicon compound can be used, for example, glycidoxy group such as γ-glycidoxypropyltrimethoxysilane (γ-GPS), γ-glycidoxypropylmethyldiethoxysilane, and the like. Containing trialkoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltriethoxysilane, β- (3,4-epoxycyclohexyl) ethyltripropoxysilane, β- (3,4-epoxycyclohexyl) ethyltributoxysilane, γ- (3,4-epoxycyclohexyl) propyltrimethoxysilane, γ- (3,4-epoxycyclohexyl) propyltriethoxysilane, δ- (3 4-epoxycyclohexyl) butyltrimethoxy Silane, epoxyalkylalkoxysilanes such as δ- (3,4-epoxycyclohexyl) butyltriethoxysilane, N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane, N- (β-aminoethyl) -γ -Aminopropylmethyldimethoxysilane, γ-aminopropylmethyldimethoxysilane, γ-aminopropylmethyldiethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N- (β-aminoethyl) -γ -Amino group-containing alkoxysilanes such as aminopropylmethyldiethoxysilane are preferred, but not particularly limited thereto. These compounds may be used alone or in combination of two or more.
The dye protective layer can be formed by applying a liquid containing the organosilicon compound on the polarizing layer by a known means such as a dipping method, a spin coating method, or a spray method, and then forming a film by heat curing. At this time, the organosilicon compound penetrates into the polarizing layer to form a layer in which the dye protective layer and the polarizing layer are substantially integrated. The thickness of the layer in which the dye protective layer and the polarizing layer are integrated is not particularly limited, but is preferably in the range of 0.05 to 1 μm.

  For the obtained polarizing element, a functional film 8 such as a hard coat film, an antireflection film, a water repellent film, a UV absorbing film, an infrared absorbing film, a photochromic film, or an antistatic film that improves the scratch resistance is provided. It can also be formed by a known method (see FIG. 1E).

  According to the above method, a high-quality polarizing element having a high concentration of 20% or less transmittance can be manufactured by a simple process. The polarizing element of the present invention is a dark-colored polarizing element having no in-plane distribution of the degree of polarization and having a transmittance of 20% or less, such as a spectacle lens, sunglasses, a display device, an optical transmission device, an automobile or a building window glass. It is widely used for optical applications, and particularly preferably used as a plastic lens for spectacles. In the case of a plastic lens for spectacles, the refractive index is usually 1.50 to 1.80, and the Abbe number is usually 30 or more.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples. In addition, the physical property evaluation of the obtained polarizing element was performed as follows.
(1) Luminous transmittance and color tone luminous transmittance and color tone was evaluated by the method described in JIS Z8701, JIS Z8729 (2 ° visual field, D ₆₅ light source). The color tone was evaluated by determining the chromaticity coordinates based on the chroma / hue (CIE 1976 (L * a * b *) color system display. The wavelength dependence of the transmittance was measured with a visible spectrophotometer, and the JIS 8701 appendix shows Calculation was performed using a given light source light spectral distribution and color matching function.

(2) Polarization degree The degree of polarization (P _eff ) is the luminous transmittance (T _// ) when the transmission axis of the polarizing element is parallel to linearly polarized light and the transmission of the polarizing element in accordance with ISO 8980-3. The luminous transmittance (T⊥) when the axis is in the orthogonal direction was determined and evaluated by calculating the following equation. The parallel transmittance and the vertical transmittance were measured using a visible spectrophotometer and a polarizer (Gran Thompson prism).
P _eff (%) = [(T _{// −} T⊥) / (T _// + T⊥)] × 100

(3) In-plane distribution of polarization degree In-plane distribution of polarization degree was prepared by sandwiching a PVA polarizing film with a triacetylcellulose (TAC) sheet on a light box (KLV-5700, manufactured by Hakuba Co., Ltd.). A polarizing sheet (polarization degree: 99.8% or more) was placed, the polarizing lenses prepared in Examples and Comparative Examples were placed on the polarizing sheet, and the transmitted light was evaluated by observing with the naked eye.

Example 1
(Manufacture of array film coating solution)
Ethanol 40 g was added to 85 g of tetraethoxysilane (TEOS) (molecular weight 208.3, trade name “KBE-04”, manufactured by Shin-Etsu Chemical Co., Ltd.) and stirred. Next, 14.75 g of 0.01 mol / L hydrochloric acid (containing 2 times the molar amount of water of TEOS) was added with stirring. The mixture was stirred for 5 minutes until it became clear.
Next, the above-mentioned mixed solution was filled in a round bottom flask equipped with a cooling pipe, the flask was heated with a mantle heater, and water at room temperature was passed through the cooling pipe to heat and reflux for 1 hour. During this time, the liquid was stirred and the liquid temperature was maintained at 75-80 ° C. Thereafter, this liquid was cooled to room temperature over 1 hour by natural cooling to obtain an array film coating stock solution. 30 g of ethanol was added to 5 g of the obtained alignment film coating stock solution, diluted and stirred to obtain alignment film coating liquid 1 (solid component: 2.5% by mass of the total coating liquid).
Here, the solid component is the stoichiometric amount when all alkoxy groups (OR group, R: alkyl group) in the alkoxysilane material are hydrolyzed to form siloxane bonds (Si—O—Si bonds). “Solid component” amount.

(Array film formation)
Using a lens made of polyurethane resin dyed by the sublimation dyeing method (refractive index 1.53, power 0.00, with hard coat, luminous transmittance 46%) as the lens substrate, the lens concave surface is coated with an array film The solution was spin-coated (approx. 2 ml was supplied at 800 rpm, held for 60 seconds), followed by heat treatment at 85 ° C. for 1 hour to cure to form an array film (sol-gel film) having a thickness of about 100 nm.

(Polishing process)
Abrasive-containing urethane foam (polishing agent: “POLIPLA103H”, manufactured by Fujimi Incorporated, average particle size 0.85 μm Al ₂ O ₃ particles, urethane foam: substantially the same shape as the curvature of the concave surface of the spherical lens ) Was applied for 10 seconds under the conditions of a rotational speed of 350 rpm and a polishing pressure of 50 g / cm ² . The lens subjected to the polishing treatment was washed with pure water and dried.

(Formation of polarizing layer)
After the lens is dried, spin coating is performed on the polished surface using 2 to 3 g of an about 5 mass% aqueous solution of a dichroic dye [trade name “Varilight solution 2S”, manufactured by Sterling Optics Inc.]. To form a polarizing layer. Spin coating was performed by supplying an aqueous dye solution at a rotation speed of 300 rpm and holding it for 8 seconds, then supplying it at a rotation speed of 400 rpm and holding it for 45 seconds, and further supplying it at 1000 rpm and holding it for 12 seconds.
Next, an aqueous solution of pH 3.5 having an iron chloride concentration of 0.15 M and a calcium hydroxide concentration of 0.2 M was prepared, and the lens obtained above was immersed in this aqueous solution for about 30 seconds, and then pulled up to obtain pure water. Wash thoroughly. By this step, the water-soluble dye is converted into hardly soluble. The thickness of the formed polarizing layer was 0.5 μm.

(Formation of dye protective film)
Thereafter, the lens was immersed in a 10% by mass aqueous solution of γ-aminopropyltriethoxysilane for 15 minutes, then washed three times with pure water, and thermally cured at 85 ° C. for 30 minutes. Further, after cooling, the lens was immersed in a 2% by mass aqueous solution of γ-glycidoxypropyltrimethoxysilane for 30 minutes in the air, and then cured in a furnace at 100 ° C. for 30 minutes and cooled after curing to form a dye protective film. Formed.

(Formation of functional film)
The lens on which the dye protective film was formed was polished with an abrasive (trade name “POLIPLA103H”, manufactured by Fujimi Incorporated, particle size 0.8 μm) and sufficiently washed.
Next, an ultraviolet curable resin (trade name “3075”, manufactured by ThreeBond Co., Ltd.) was applied by spin coating (supplied at 500 rpm, held for 45 seconds). After coating, the film was cured with an ultraviolet irradiation device at a UV irradiation light amount of 600 mJ / cm ² and a hard coat was applied to the lens.
Table 1 shows the measurement results of luminous transmittance, saturation / hue (CIE 1976 (L * a * b *) color system display), and polarization efficiency in the lens substrate and the polarizing lens. As a result, a slightly greenish polarizing lens having a low luminous transmittance was obtained.

Example 2
Example 1 except that a polythiourethane resin lens (refractive index 1.67, power 0.00, with hard coat, luminous transmittance 43%) dyed by the sublimation dyeing method was used as the lens substrate. Similarly, a polarizing lens was produced. A slightly reddish gray polarized lens with low transmittance was obtained. Inhomogeneity of the polarization degree in the lens surface was not observed. The results are shown in Table 1.

Example 3
As in Example 1, except that a polysulfide resin lens (refractive index: 1.70, power: 0.00, hard coat, luminous transmittance: 47%) dyed by the sublimation dyeing method was used as the lens substrate. A polarizing lens was produced. A slightly purpleish gray polarized lens with low transmittance was obtained. Inhomogeneity of the polarization degree in the lens surface was not observed. The results are shown in Table 1.

Example 4
As a lens base material, a polycarbonate lens base material (refractive index 1.59, power 0.00, with hard coat, luminous transmittance 45%) dyed by an immersion method is used. A polarizing lens was produced in the same manner as in Example 1 except that the above method was used.
Polishing using a polishing agent ("POLIPLA103H", manufactured by Fujimi Incorporated, average particle size 0.8 μm Al ₂ O ₃ particles, urethane foam: approximately the same shape as the curvature of the convex surface of the spherical lens) on the hard coat surface of the lens convex surface To improve the surface. After thoroughly cleaning the surface, an alignment film was formed in the same manner as in Example 1.
As a result, as in Example 1, a slightly greenish polarizing lens with low transmittance was obtained. Inhomogeneity of the polarization degree in the lens surface was not observed. The results are shown in Table 1.

Comparative Examples 1 and 2
A monomer is injected into a cavity in which a PVA polarizing film (Polatechno Co., Ltd., GREY-15B, luminous transmittance of 15%) subjected to curve processing is inserted and fixed, and subjected to heat curing treatment. Allyl resin substrate (refractive index 1.50, luminous transmittance 92% (when no film is inserted)) or polythiourethane resin substrate (refractive index 1.67, luminous transmittance 88% (film A polarizing lens in which a polarizing film was inserted and fixed in the case of not inserting) was prepared. The luminous transmittances of the obtained polarizing lenses were all 15%. When the non-uniformity of the polarization degree in the lens plane was observed, clear brightness and darkness were observed in each lens in the form of a cross parallel to and orthogonal to the absorption axis direction of the polarization lens. It was found to be non-uniform.

Comparative Example 3
A polarizing lens was produced in the same manner as in Example 1 except that a lens made of an unstained polyurethane resin (luminous transmittance 91%) was used as the lens substrate. The luminous transmittance of the polarizing lens was 29%.
The thickness of the formed polarizing layer was 0.5 μm.

Comparative Example 4
In order to further increase the amount of dye spin-coated on the lens surface, a polarizing lens was produced in the same manner as in Comparative Example 3 except that a polarizing layer was formed under the following spin coating conditions.
The spin coating was performed by supplying 5 g of an aqueous dye solution at a rotation speed of 200 rpm, holding for 8 seconds, then holding at a rotation speed of 300 rpm for 45 seconds, and further holding at 800 rpm for 12 seconds. The thickness of the formed polarizing layer was 0.65 μm.
The luminous transmittance of the obtained polarizing lens was 25%. Moreover, the hue was hardly different from that of Comparative Example 3, and it was difficult to distinguish visually.

Comparative Example 5
In order to further increase the amount of dye spin-coated on the lens surface, a polarizing lens was produced in the same manner as in Comparative Example 3 except that a polarizing layer was formed under the following spin coating conditions.
Spin coating was performed by supplying 8 g of an aqueous dye solution at a rotation speed of 150 rpm, holding for 8 seconds, holding at a rotation speed of 200 rpm for 45 seconds, and further holding at 650 rpm for 12 seconds. The thickness of the formed polarizing layer was 0.7 μm.
In the obtained polarizing lens, uneven density was observed. As an average value, the luminous transmittance was 23%. The degree of polarization was as low as 90%. The cloudiness which can be visually recognized also generate | occur | produced and the performance as a polarizing lens was completely inadequate.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the polarizing element which can be manufactured with a simple process and has a high density | concentration of 20% or less of the transmittance | permeability can be provided. In addition, a polarizing element can be efficiently produced by the production method, and a dark polarizing element having a transmittance of 20% or less and having no in-plane distribution of the degree of polarization can be provided. The polarizing element can freely adjust the transmission color while maintaining the polarization characteristics, and is widely applied to optical applications such as eyeglass lenses, sunglasses, display devices, light transmission devices, window windows of automobiles and buildings, etc. In particular, it can be suitably used as a plastic lens for spectacles.

DESCRIPTION OF SYMBOLS 1; Base material 2; Hard-coat layer 3; Adhesion layer 4; Arrangement film 5; Arrangement layer 6; Polarizing layer (arranged dye layer)
7; Dye protective film (protective layer)
8; Functional film (water repellent film, etc.)

Claims (6)

The manufacturing method of the polarizing element which has the following process I-process IV.
Step I: Using a base material dyed with a luminous transmittance of 75% or less, an alkoxysilane represented by the following general formula (1) and / or a hexagon represented by the following general formula (2) on the base material Step of depositing an alignment film containing at least an alkoxydisiloxane (A) to form an alignment film Si (OR ¹ ) _a (R ² ) _4-a (1)
_{^{(R 3 O) 3 Si-}} O-Si (OR 4) 3 (2)
(Wherein R ¹ , R ³ and R ⁴ are each independently an alkyl group having 1 to 5 carbon atoms, R ² is an alkyl group having 1 to 10 carbon atoms, and a is 3 or 4. .)
Step II: A step of polishing the alignment film formed in Step I in a uniaxial direction to form an alignment layer having polishing marks in a uniaxial direction Step III: A dichroic dye on the alignment layer formed in Step II Forming a polarizing layer by arranging and depositing layers Step IV: forming a protective layer for fixing a dye on the polarizing layer formed in Step III   The method for producing a polarizing element according to claim 1, wherein the alignment film formed in Step I is a sol-gel film.   The alignment film coating solution is a mixture containing the alkoxysilane and / or hexaalkoxydisiloxane (A), water (B) and alcohols (C) at 40 to 120 ° C. for 0.5 to 24 hours. The method for producing a polarizing element according to claim 1, wherein the polarizing element is prepared by heat treatment.   The manufacturing method of the polarizing element of Claim 3 which heat-refluxes the mixture containing (A)-(C) component in the heat processing of the process I.   The component (A) is selected from the group consisting of tetraethoxysilane, tetramethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, tetraisopropoxysilane, methyltriisopropoxysilane, hexaethoxydisiloxane, and hexamethoxydisiloxane. The manufacturing method of the polarizing element in any one of Claims 1-4 which is 1 or more types.   The polarizing element obtained by the manufacturing method in any one of Claims 1-5.

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