WO2009088030A1

WO2009088030A1 - Dye-based polarizer, polarizing plate and method for producing the dye-based polarizer

Info

Publication number: WO2009088030A1
Application number: PCT/JP2009/050107
Authority: WO
Inventors: Noriaki Mochizuki; Yuichi Sadamitsu
Original assignee: Nippon Kayaku Kabushiki Kaisha; Polatechno Co., Ltd.
Priority date: 2008-01-11
Filing date: 2009-01-08
Publication date: 2009-07-16
Also published as: TW200937054A; JP2011053234A

Abstract

Disclosed is a polarizing plate composed of a polarizer which is made of a hydrophilic polymer containing at least one dichroic dye and silicon or a silicon compound. The polarizing plate is suppressed in transmittance change even in a light resistance test using light of high intensity such as light of an ultra high-pressure mercury lamp. The polarizing plate is also suppressed in transmittance change in a heat resistance test. A liquid crystal projector exhibiting stable performance after long use can be obtained by using the polarizing plate.

Description

Dye-type polarizing element, polarizing plate, and method for producing the same

The present invention relates to a dye-type polarizing element, a polarizing plate using the same, and a method for producing the same.

In general, a polarizing element is produced by adsorbing and orienting iodine or dichroic dye, which is a dichroic dye, on a polyvinyl alcohol-based resin film. A protective film made of triacetyl cellulose or the like is bonded to at least one surface of the polarizing element via an adhesive layer to form a polarizing plate, which is used for a liquid crystal display device or the like. A polarizing plate using iodine as a dichroic dye is called an iodine polarizing plate, while a polarizing plate using a dichroic dye as a dichroic dye is called a dye polarizing plate. Among these, the dye-based polarizing plate has a problem that the transmittance is low compared with the polarizing plate having the same degree of polarization as that of the iodine-based polarizing plate, that is, the contrast is low. It is used in color liquid crystal projectors and the like.
In the case of a color liquid crystal projector, a polarizing plate is used for the liquid crystal image forming portion. However, light is greatly absorbed by the polarizing plate, and an image that is projected from several tens of inches to hundreds of tens of inches is reduced to 0.5. In order to collect light on a polarizing plate having a small area of ˜6 inches, deterioration due to light and the influence of heat upon irradiation with light are inevitable due to the size of the light density.

JP 2000-112022 JP2007-256898 Japanese Patent No. 3357109 US Patent: US4818624

The demand for further brightness improvement of liquid crystal projectors is persistent, and the light density increases with the downsizing of polarizing plates, so the light resistance and heat resistance for long-term use by the light is high, and the initial optical characteristics are maintained, and There is a need for polarizing plates having high contrast. In response to such a request, Patent Document 1 and Patent Document 2 disclose a method of providing a heat-radiating substrate in order to release heat generated in the polarizing plate. Light resistance is insufficient. Furthermore, in recent years, there has been a problem that the parallel transmittance obtained by measuring the light density and the amount of heat so that the absorption axis direction of the polarizing plate becomes parallel (hereinafter referred to as burning) is greatly reduced. Newly occurring. Burning particularly occurs in a polarizing plate for a blue light source of a liquid crystal projector, and the improvement thereof has been demanded. Until now, measures such as cooling the polarizing plate by blowing air have been taken, but it is still insufficient. Further, there has never been a technique that can suppress the occurrence of burning by improving the polarizing plate itself, and it has been desired to improve the durability of the polarizing plate itself against light and / or heat and to improve the burning.

For such a problem, as a technique for improving the heat resistance of the polarizing plate, there is a technique for improving durability against heat with a polyhydric aldehyde as in Patent Document 3. However, it is still not sufficient, and further improvement in heat resistance is desired.

Further, Patent Document 4 discloses a technique for suppressing a color change by treating a polarizing plate having a polyene structure with a silane coupling agent in order to improve high temperature heat resistance and durability. However, it is not a technique that can improve the durability against light and / or heat of a dye-type polarizing plate containing a dichroic dye and improve burning.

As a result of intensive studies to solve the above-mentioned problems, the present inventors have developed a polarizing element comprising at least one dichroic dye and a hydrophilic polymer containing silicon or a silicon compound. Alternatively, it was newly found that the durability against heat can be improved and the burning can be improved.

That is, the present invention
(1) A polarizing element comprising a hydrophilic polymer containing at least one dichroic dye and silicon or a silicon compound.
(2) The polarizing element according to (1), wherein the dichroic dye is an azo dye.
(3) The polarizing element according to (1) or (2), wherein the silicon compound is a silane coupling agent.
(4) The polarizing element according to (3), wherein the silane coupling agent contains an amino group.
(5) The polarizing element according to any one of (1) to (4), wherein the hydrophilic polymer is made of a polyvinyl alcohol-based resin film and is stretched.
(6) The polarizing plate comprising the polarizing element according to any one of (1) to (5), wherein a protective layer is provided on one side or both sides of the polarizing element.
(7) The polarizing plate according to (6), which is for a liquid crystal projector.
(8) The polarizing plate according to (7), which is for a blue light source.
(9) A liquid crystal display device provided with the polarizing element or polarizing plate according to any one of (1) to (6).
(10) A liquid crystal projector provided with the polarizing element or the polarizing plate according to any one of (1) to (8).
(11) The hydrophilic polymer containing at least one dichroic dye is treated with a solution containing silicon or a silicon compound and then immediately dried (1) to (5) The manufacturing method of the polarizing element of one term.

The polarizing element of the present invention and its polarizing plate greatly improve the heat resistance, and under a light resistance test, improve the durability against light and / or heat, leading to the obtaining of a polarizing element and a polarizing plate that can improve burning. It was.

Hereinafter, the present invention will be described in detail.
The polarizing element of the present invention comprises a hydrophilic polymer containing at least one dichroic dye and silicon or a silicon compound. The hydrophilic polymer is not particularly limited, and examples thereof include polyvinyl alcohol resins, amylose resins, starch resins, cellulose resins, and polyacrylate resins. A dichroic dye is dyed on a film made of these resins and stretched to obtain a polarizing plate having dichroism. A film made of a polyvinyl alcohol-based resin is most preferable from the viewpoint of dyeability and crosslinkability when a dichroic dye is contained.

Hereinafter, a specific method for manufacturing a polarizing element will be described using a polyvinyl alcohol resin film as an example.
The manufacturing method of the polyvinyl alcohol-type resin which comprises a polarizing element is not specifically limited, It can manufacture by a well-known method. For example, the polyvinyl alcohol resin can be obtained by saponifying a polyvinyl acetate resin. Examples of the polyvinyl acetate-based resin include polyvinyl acetate, which is a homopolymer of vinyl acetate, and copolymers of vinyl acetate and other monomers copolymerizable therewith. Examples of other monomers copolymerized with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, and unsaturated sulfonic acids. The saponification degree of the polyvinyl alcohol-based resin is usually preferably from 85 to 100 mol%, more preferably 95 mol% or more. This polyvinyl alcohol-based resin may be further modified, and for example, polyvinyl formal or polyvinyl acetal modified with aldehydes may be used. The degree of polymerization of the polyvinyl alcohol resin is usually preferably from 1,000 to 10,000, more preferably from 1,500 to 5,000.

A film made of such a polyvinyl alcohol resin is used as a raw film. The method for forming a polyvinyl alcohol-based resin is not particularly limited, and can be formed by a known method. In this case, the polyvinyl alcohol-based resin film can contain glycerin, ethylene glycol, propylene glycol, low molecular weight polyethylene glycol, or the like as a plasticizer. The amount of plasticizer is preferably 5 to 20% by weight, more preferably 8 to 15% by weight. The thickness of the raw film made of polyvinyl alcohol resin is not particularly limited, but is preferably 5 to 150 μm, and more preferably 10 to 100 μm.

The polyvinyl alcohol resin film is first subjected to a swelling process. The swelling step is performed by immersing the polyvinyl alcohol resin film in a solution at 20 to 50 ° C. for 30 seconds to 10 minutes. The solution is preferably water. When the time for manufacturing the polarizing element is shortened, the swelling step can be omitted because the swelling occurs even during the dyeing process.

The dyeing process is performed after the swelling process. The dyeing step is performed by immersing the polyvinyl alcohol-based resin film in a solution containing a dichroic dye. The solution temperature in this step is preferably 5 to 60 ° C, more preferably 20 to 50 ° C, and particularly preferably 35 to 50 ° C. The time for dipping in the solution can be adjusted moderately, but is preferably adjusted from 30 seconds to 20 minutes, more preferably from 1 to 10 minutes. The dyeing method is preferably immersed in the solution, but can also be performed by applying the solution to a polyvinyl alcohol-based resin film.

The solution containing the dichroic dye can contain sodium chloride, sodium sulfate, anhydrous sodium sulfate, sodium tripolyphosphate and the like as a dyeing assistant. Their content can be adjusted at any concentration depending on the time and temperature depending on the dyeability of the dye, but the respective content is preferably 0 to 5% by weight, more preferably 0.1 to 2% by weight.

Here, the dichroic dye is not particularly limited, and any dichroic dye such as azo, anthraquinone or quinophthalone may be used as long as it dyes a hydrophilic polymer. For example, an azo-based dichroic compound as shown in Non-Patent Document 1 can be used, and those having high dichroism are particularly preferable. Examples of dyes having high dichroism include C.I. Ai. direct. Yellow 12, sea. Ai. direct. Yellow 28, Sea. Ai. direct. Yellow 44, Sea. Ai. direct. Orange 26, Sea. Ai. direct. Orange 39, sea. Ai. direct. Orange 107, sea. Ai. direct. Red 2, sea. Ai. direct. Red 31, sea. Ai. direct. Red 79, Sea. Ai. direct. Red 81, Sea. Ai. direct. Red 247, Sea. Ai. direct. Green 80, Sea. Ai. direct. Green 59, and JP 2001-33627, JP 2002-296417, JP 2003-215338, WO 2004/092822, JP 2001-0564112, JP 2001-027708, JP 11-218611, JP 11-218610 and Examples thereof include organic dyes described in JP-A-60-156759. These organic dyes can be used as free metal, alkali metal salts (for example, Na salt, K salt, Li salt), ammonium salts, or amine salts. However, the dichroic dye is not limited to these, and a known dichroic compound can be used, but an azo dye is preferable.

Other than the dichroic dyes shown in these, other organic dyes can be used in combination as required. Depending on whether the target polarizing element is a neutral color polarizing element, a color polarizing element for liquid crystal projectors, or other color polarizing elements, the types of organic dyes to be blended differ. The blending ratio is not particularly limited, and the blending amount can be arbitrarily set according to demands such as a light source and a hue.

After the dyeing process, a cleaning process (hereinafter referred to as cleaning process 1) can be performed before entering the next process. The dyeing process 1 is a process of washing the dye solvent adhering to the surface of the polyvinyl alcohol resin film in the dyeing process. By performing the washing step 1, it is possible to suppress the migration of the dye into the liquid to be processed next. In the cleaning step 1, water is generally used. The washing method is preferably immersed in the solution, but can be washed by applying the solution to a polyvinyl alcohol resin film. The washing time is not particularly limited, but is preferably 1 to 300 seconds, more preferably 1 to 60 seconds. The temperature of the solvent in the washing step 1 needs to be a temperature at which the hydrophilic polymer does not dissolve. Generally, it is washed at 5 to 40 ° C.

After the dyeing step or washing step 1, a step of adding a crosslinking agent and / or a water resistance agent can be performed. Examples of the crosslinking agent include boron compounds such as boric acid, borax or ammonium borate, polyvalent aldehydes such as glyoxal or glutaraldehyde, polyisocyanate compounds such as biuret type, isocyanurate type or block type, titanium oxy Titanium compounds such as sulfate can be used, but ethylene glycol glycidyl ether, polyamide epichlorohydrin, and the like can also be used. Examples of the water-resistant agent include succinic peroxide, ammonium persulfate, calcium perchlorate, benzoin ethyl ether, ethylene glycol diglycidyl ether, glycerin diglycidyl ether, ammonium chloride or magnesium chloride, preferably boric acid. Used. The step of containing a crosslinking agent and / or a water-resistant agent is performed using at least one kind of crosslinking agent and / or a water-resistant agent shown above. As a solvent in that case, water is preferable, but it is not limited. The concentration of the cross-linking agent and / or the water-proofing agent in the solvent in the step of adding the cross-linking agent and / or the water-proofing agent is 0.1 to 6.0 when boric acid is used as an example. % By weight is preferable, and 1.0 to 4.0% by weight is more preferable. The solvent temperature in this step is preferably 5 to 70 ° C, more preferably 5 to 50 ° C. Although it is preferable to immerse the polyvinyl alcohol-based resin film in the solution with a crosslinking agent and / or a waterproofing agent, the solution may be applied to or applied to the polyvinyl alcohol-based resin film. The treatment time in this step is preferably 30 seconds to 6 minutes, more preferably 1 to 5 minutes. However, if it is not necessary to contain a crosslinking agent and / or a water-resistant agent and it is desired to shorten the time, this treatment step may be omitted if a crosslinking treatment or a water-resistant treatment is unnecessary. .

After the dyeing step, the washing step 1, or the step of adding a crosslinking agent and / or a water resistance agent, the stretching step is performed. The stretching step is a step of stretching the polyvinyl alcohol film uniaxially. The stretching method may be either a wet stretching method or a dry stretching method.

In the case of the dry stretching method, when the stretching heating medium is an air medium, the temperature of the air medium is preferably stretched at a room temperature to 180 ° C. The treatment is preferably performed in an atmosphere of 20 to 95% RH. Examples of the heating method include an inter-roll zone stretching method, a roll heating stretching method, a pressure stretching method, an infrared heating stretching method, and the like, but the stretching method is not limited. The stretching step can be performed in one step, but can also be performed by two or more multi-step stretching.

In the case of the wet stretching method, stretching is performed in water, a water-soluble organic solvent, or a mixed solution thereof. It is preferable to perform the stretching treatment while being immersed in a solution containing a crosslinking agent and / or a water resistance agent. Examples of the crosslinking agent include boron compounds such as boric acid, borax or ammonium borate, polyvalent aldehydes such as glyoxal or glutaraldehyde, polyisocyanate compounds such as biuret type, isocyanurate type or block type, titanium oxy Titanium compounds such as sulfate can be used, but ethylene glycol glycidyl ether, polyamide epichlorohydrin, and the like can also be used. Examples of water-proofing agents include succinic peroxide, ammonium persulfate, calcium perchlorate, benzoin ethyl ether, ethylene glycol diglycidyl ether, glycerin diglycidyl ether, ammonium chloride, and magnesium chloride. Stretching is performed in a solution containing at least one or more crosslinking agents and / or water resistance agents as described above. The crosslinking agent is preferably boric acid. The concentration of the crosslinking agent and / or waterproofing agent in the stretching step is preferably, for example, 0.5 to 15% by weight, and more preferably 2.0 to 8.0% by weight. The draw ratio is preferably 2 to 8 times, more preferably 5 to 7 times. The stretching temperature is preferably 40 to 60 ° C, more preferably 45 to 58 ° C. The stretching time is usually from 30 seconds to 20 minutes, more preferably from 2 to 5 minutes. The wet stretching process can be performed in one stage, but can also be performed by multistage stretching of two or more stages.

After performing the stretching step, the film surface may be subjected to a cleaning step (hereinafter referred to as a cleaning step 2) because the cross-linking agent and / or waterproofing agent may precipitate or foreign matter may adhere to the film surface. it can. The washing time is preferably 1 second to 5 minutes. The washing method is preferably immersed in a washing solution, but the solution can be washed on the polyvinyl alcohol resin film by coating or coating. The cleaning process can be performed in one stage, and the multi-stage process of two or more stages can be performed. The solution temperature in the washing step is not particularly limited, but is usually 5 to 50 ° C., preferably 10 to 40 ° C.

As the solvent used in the treatment steps so far, for example, water, dimethyl sulfoxide, N-methylpyrrolidone, methanol, ethanol, propanol, isopropyl alcohol, glycerin, ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol or triethylene glycol Examples of the solvent include, but are not limited to, alcohols such as methylolpropane, and amines such as ethylenediamine or diethylenetriamine. A mixture of one or more of these solvents can also be used. The most preferred solvent is water.

After the stretching process or washing process 2, a film drying process is performed. The drying process can be performed by natural drying, but in order to further improve the drying efficiency, the surface can be removed by compression with a roll, an air knife, a water absorption roll, etc., and / or blow drying is performed. You can also. The drying treatment temperature is preferably 20 to 100 ° C., more preferably 60 to 100 ° C. A drying treatment time of 30 seconds to 20 minutes can be applied, but 5 to 10 minutes is preferable.

In the present invention, a method of immersing a polyvinyl alcohol-based resin film in a solution containing a silicon compound in any step from the dyeing step of dyeing a polyvinyl alcohol-based resin film with a dichroic dye to the cleaning step 2, Alternatively, silicon or a silicon compound is contained by a method of coating or coating a solution containing a silicon compound after the step of washing the stretched film. In the case of the method by immersion, specifically, among the manufacturing steps of the polarizing element described above, a dyeing step of dyeing a polyvinyl alcohol-based resin film with a dichroic dye, and a washing step 1, 2 after dyeing of the dichroic dye Any of the process of making a polyvinyl alcohol-type resin film containing a chromatic dye contain a crosslinking agent and / or a waterproofing agent, the stretching process of stretching in a solution containing a crosslinking agent, and the cleaning process 2 of washing the stretched film Or need to be treated with a solution containing a silicon compound in multiple steps. In the case of the coating or coating method, for example, there are spin coating, gravure coating, die coating, lip coating and the like, but there is no particular limitation, and a known method can be used. The treatment method is not limited as long as it is a method in which a solution containing a silicon compound is brought into contact with a polyvinyl alcohol-based resin film, and a known method can be used. The most preferred method is a method of immersing a polyvinyl alcohol resin film in a solution containing a silicon compound. In particular, in the washing step 2 after the stretching treatment, it is preferable that the silicon compound-containing solution is treated, followed by a drying step. Further, the drying treatment temperature is 80 ° C. or higher, so that burning resistance and heat resistance are increased. Can be improved.

The silicon compound is not particularly limited as long as it is a general silicon compound, for example. The function is exhibited by immersing the silicon compound in the hydrophilic polymer. As the silicon compound, compounds generally called a functional silane compound, a silylating agent, a silicon crosslinking agent, and a silane coupling agent can be used.

Examples of such silicon compounds include methyl triisocyanate silane (Matsumoto Fine Chemicals SI-310), tetraisocyanate silane (Matsumoto Fine Chemicals SI-400), methyltrichlorosilane (Shin-Etsu Chemical KA-13), methyl Dichlorosilane (KA-12 manufactured by Shin-Etsu Chemical Co., Ltd.), dimethyldichlorosilane (KA-22 manufactured by Shin-Etsu Chemical Co., Ltd.), trimethylchlorosilane (KA-31 manufactured by Shin-Etsu Chemical Co., Ltd.), phenyltrichlorosilane (KA-103 manufactured by Shin-Etsu Chemical Co., Ltd.), Diphenyldichlorosilane (KA-202, Shin-Etsu Chemical Co., Ltd.), tetramethoxysilane (KBM-04, Shin-Etsu Chemical Co., Ltd.), methyltrimethoxysilane (KBM-13, Shin-Etsu Chemical Co., Ltd.), dimethyldimethoxysilane (KBM-22), Feni Trimethoxysilane (KBM-103), tetraethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd. KBE-04), diphenyldimethoxysilane (KBM-202SS), methyltriethoxysilane (KBE-13), dimethyldiethoxysilane (KBE-22) Phenyltriethoxysilane (KEB-103), Diphenyldiethoxysilane (KBE-202), Hexyltrimethoxysilane (KBM-3063), Hexyltriethoxysilane (LS-3063), Decyltrimethoxysilane (KBM-3103) Decyltrimethoxysilane (KBM-3103C) or trifluoropropyltrimethoxysilane (KBM-7103).

Of the silicon compounds, silane coupling agents are particularly preferred. The silane coupling agent is represented by the following chemical structural formula (A) or (B) as a typical compound, and has at least two different functional groups having different reactivity in one molecule.

(In the above, as X, for example, a reactive group such as vinyl group, epoxy group, amino group, methacryl group, mercapto group, etc., as OR, for example, methoxy group, ethoxy group, as R, for example, methyl group, ethyl group, etc. To express)

Also, the alkoxysilyl group (Si-OR) of the silane coupling agent is hydrolyzed with water to become a silanol group. The polyvinyl alcohol-type resin film is processed using the hydrolyzed silane coupling agent having the silanol group. In order to hydrolyze to a silanol group, for example, the silane coupling agent is gradually added to sufficiently stirred water, and the treatment is performed by stirring for 30 minutes. Since the silanol group produced by hydrolysis is unstable in an aqueous solution, it is necessary to control the aqueous solution at an appropriate pH in order to stabilize it in the aqueous solution. The pH of the dissolved aqueous solution is adjusted to a pH suitable for each silane compound. For example, pH 7 to 11 is suitable for a silane coupling agent having an amino group, and other silane cups. For example, pH of 3 to 5 is appropriate for the ring agent, but not limited thereto, and adjustment at an appropriate pH is preferable.

Specific silane coupling agents used in the present invention include, for example, vinyltrichlorosilane (KA-1003 manufactured by Shin-Etsu Chemical Co., Ltd.), vinyltrimethoxysilane (KBM-1003 manufactured by Shin-Etsu Chemical Co., Ltd.), vinyltriethoxysilane ( Shin-Etsu Chemical KBE-1003), vinyltris (β-methoxyethoxy) silane (Shin-Etsu Chemical KBC-1003), β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane (Shin-Etsu Chemical KBM-303) Γ-glycidoxypropyltrimethoxysilane (KBE-403 manufactured by Shin-Etsu Chemical Co., Ltd.), γ-glycidoxypropylmethyldiethoxysilane (KBE-402 manufactured by Shin-Etsu Chemical Co., Ltd.), γ-glycidoxypropyltriethoxysilane ( Shin-Etsu Chemical KBE-403), γ-methacryloxyp Pyrmethyldimethoxysilane (Shin-Etsu Chemical KBM-502), γ-methacryloxypropyltrimethoxysilane (Shin-Etsu Chemical KBM-503), γ-methacryloxypropylmethyldiethoxysilane (Shin-Etsu Chemical KBE-502) ), Γ-methacryloxypropyltriethoxysilane (KBE-503 manufactured by Shin-Etsu Chemical Co., Ltd.), γ-methacryloxypropyltrimethoxysilane (SZ-6030 manufactured by Toray Dow Coating Silicone Co., Ltd.), N-β- (N-vinyl) Benzylaminoethyl) -γ-aminopropyltrimethoxysilane hydrochloride (SZ-6032 manufactured by Toray Dow Coating Silicone), γ-aminopropyltrimethoxysilane (SZ-6083 manufactured by Toray Dow Coating Silicone), γ -Diallylaminopropyl Rimethoxysilane (Toray Dow Coating Silicone AX43-065), N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane (Shin-Etsu Chemical KBM-602), N-β (aminoethyl) -γ -Aminopropyltrimethoxysilane (KBE-603, Shin-Etsu Chemical Co., Ltd.), N-β- (aminoethyl) -γ-aminopropyltriethoxysilane (KBE-603, Shin-Etsu Chemical Co., Ltd.), γ-aminopropyltrimethoxysilane ( Shin-Etsu Chemical KBM-903), γ-aminopropyltriethoxysilane (Shin-Etsu Chemical KBM-903), N-phenyl-γ-aminopropyltrimethoxysilane (Shin-Etsu Chemical KBM-573), γ- ( 2-Aminoethyl) aminopropyltrimethoxysilane (Toray Dow Coating Shi Rikon SH6020), γ- (2-aminoethyl) aminopropylmethyldimethoxysilane (Toray Dow Coating Silicone SH6023), γ-chloropropyltrimethoxysilane (Shin-Etsu Chemical KBM-703), γ- Mercaptopropyltrimethoxysilane (KBM-803 manufactured by Shin-Etsu Chemical Co., Ltd.), Silaace S210 (manufactured by Chisso), Silaace S220 (manufactured by Chisso), Silaace S310 (manufactured by Chisso), Silaace S320 (manufactured by Chisso), Silaace S330 ( Chisso Corp.), Sila Ace S510 (Chisso Corp.), Sila Ace S520 (Chisso Corp.), Sila Ace S530 (Chisso Corp.), Sila Ace S710 (Chisso Corp.), Sila Ace S810 (Chiso Corp.) or Sila Ace S There is a 50 (manufactured by Chisso Corporation).

Among them, a silane coupling agent having an amino group, for example, N-β- (N-vinylbenzylaminoethyl) -γ-aminopropyltrimethoxysilane hydrochloride (SZ-6032 manufactured by Toray Dow Coating Silicone) Γ-aminopropyltrimethoxysilane (SZ-6083 manufactured by Toray Dow Coating Silicone), γ-diallylaminopropyltrimethoxysilane (AX43-065 manufactured by Toray Dow Coating Silicone), N-β (aminoethyl) ) -Γ-aminopropylmethyldimethoxysilane (Shin-Etsu Chemical KBM-602), N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane (Shin-Etsu Chemical KBM-603), N-β (amino Ethyl) -γ-aminopropyltriethoxysilane (Shin-Etsu GBE-603), γ-aminopropyltrimethoxysilane (KBM-903, Shin-Etsu Chemical), γ-aminopropyltriethoxysilane (KBM-903, Shin-Etsu Chemical), N-phenyl-γ-aminopropyl Trimethoxysilane (KBE-573 manufactured by Shin-Etsu Chemical Co., Ltd.), γ- (2-aminoethyl) aminopropyltrimethoxysilane (SH6020 manufactured by Toray Dow Coating Silicone Co., Ltd.) or γ- (2-aminoethyl) aminopropylmethyldimethoxy Silane (Toray Dow Coating Silicone SH6023) is preferred, more preferably N-β (aminoethyl) -γ-aminopropylmethyldimethoxysilane having an amino group at the molecular end (Shin-Etsu Chemical KBM-602). N-β- (aminoethyl) -γ-amino Propyltrimethoxysilane (Shin-Etsu Chemical KBM-603), N-β- (aminoethyl) -γ-aminopropyltriethoxysilane (Shin-Etsu Chemical KBE-603), γ-aminopropyltrimethoxysilane (Shin-Etsu Chemical) KBM-903), γ-aminopropyltriethoxysilane (KBM-903 manufactured by Shin-Etsu Chemical Co., Ltd.), γ- (2-aminoethyl) aminopropyltrimethoxysilane (SH6020 manufactured by Toray Dow Coating Silicone) or γ -(2-Aminoethyl) aminopropylmethyldimethoxysilane (SH6023 manufactured by Toray Dow Coating Silicone) is more preferable.

The concentration of the silicon compound in the aqueous solution is not particularly limited as long as the silicon compound is dissolved, but is preferably 0.01% by weight to 10% by weight, more preferably 0.1% by weight to 5% by weight. It is as follows. When the solubility of the silicon compound is low, a mixed solution of a solvent different from the main solvent, for example, a mixed solution such as water and an alcohol solvent can be used.

As one method for confirming the content of the silicon compound relative to the polyvinyl alcohol-based resin film, a method of analyzing the silicon compound itself may be used, but the amount of silicon contained may be indirectly confirmed. In this case, the silicon is subjected to Inductively Coupled Plasma emission analysis (hereinafter abbreviated as ICP emission analysis). Specifically, about 0.1 g of a polarizing element is put in a platinum crucible and weighed, 0.5 g of lithium tetraborate is added so as to cover the top of the sample, dissolved at 1000 ° C. for 2 hours, and then 15 ml of 50 wt% hydrochloric acid. The content of silicon can be confirmed by constant volume ICP emission analysis in 50 ml which is dissolved by heating and dissolved completely.

ICP emission analysis can not only confirm the presence of silicon, but also perform quantification. If the amount of silicon contained in the polarizing element is 5 ppm or more, it can be confirmed that silicon is contained, and the amount expresses the effect of the present invention. In order to obtain the effects of the present invention, it is preferably contained in an amount of 100 to 30000 ppm, more preferably 300 to 1000 ppm. When the amount of silicon reaches the upper limit in the IPC emission spectrometer, it may be measured after diluting to an arbitrary concentration. If it is less than 5 ppm, the effects of the present invention may not be sufficiently exhibited.

By the above method, a polyvinyl alcohol-based resin film polarizing element with improved durability according to the present invention can be obtained. Even if the film for adsorbing the dichroic dye in the polarizing element is not a polyvinyl alcohol resin, a film obtained from an amylose resin, a starch resin, a cellulose resin, a polyacrylate resin, etc. The same polarizing element can be produced by containing and orienting the hydrophilic resin by stretching, shear orientation or the like.

The obtained polarizing element is made into a polarizing plate by providing a transparent protective layer on one side or both sides thereof. The transparent protective layer can be provided as a polymer coating layer or as a film laminate layer. The transparent polymer or film forming the transparent protective layer is preferably a transparent polymer or film having high mechanical strength and good thermal stability. Examples of substances used as the transparent protective layer include cellulose acetate resins such as triacetyl cellulose and diacetyl cellulose or films thereof, acrylic resins or films thereof, polyvinyl chloride resins or films thereof, polyester resins or films thereof, polyarylate resins or The film, a cyclic polyolefin resin having a cyclic olefin such as norbornene or the film thereof, polyethylene, polypropylene, a polyolefin having a cyclo or norbornene skeleton or a copolymer thereof, and the main chain or side chain of which is imide and / or amide Examples thereof include a resin, a polymer, or a film thereof. In addition, a resin having liquid crystallinity or a film thereof can be provided as the transparent protective layer. The thickness of the protective film is, for example, about 0.5 to 200 μm. A polarizing plate is produced by providing one or more layers of the same or different types of resins or films on one side or both sides.

An adhesive is required to bond the transparent protective layer to the polarizing element. Although it does not specifically limit as an adhesive agent, A polyvinyl alcohol-type adhesive agent is preferable. Examples of the polyvinyl alcohol-based adhesive include, but are not limited to, Gohsenol NH-26 (manufactured by Nihon Gosei Co., Ltd.), EXEVAL RS-2117 (manufactured by Kuraray Co., Ltd.), and the like. A cross-linking agent and / or a waterproofing agent can be added to the adhesive. As the polyvinyl alcohol-based adhesive, a maleic anhydride-isobutylene copolymer is used, but if necessary, an adhesive mixed with a crosslinking agent can be used. As maleic anhydride-isobutylene copolymers, for example, isoban # 18 (manufactured by Kuraray), isoban # 04 (manufactured by Kuraray), ammonia-modified isoban # 104 (manufactured by Kuraray), ammonia-modified isoban # 110 (manufactured by Kuraray) ), Imidized isoban # 304 (manufactured by Kuraray), imidized isoban # 310 (manufactured by Kuraray), and the like. A water-soluble polyvalent epoxy compound can be used as the crosslinking agent at that time. Examples of the water-soluble polyvalent epoxy compound include Denacol EX-521 (manufactured by Nagase Chemtech) and Tetrat-C (manufactured by Mitsui Gas Chemical Co., Ltd.). Moreover, as adhesives other than polyvinyl alcohol-type resin, well-known adhesives, such as urethane type, an acrylic type, and an epoxy type, can also be used. Further, for the purpose of improving the adhesive strength of the adhesive or improving the water resistance, additives such as zinc compounds, chlorides, iodides and the like can be simultaneously contained at a concentration of about 0.1 to 10% by weight. The additive is not limited. After laminating the transparent protective layer with an adhesive, the polarizing plate is obtained by drying or heat treatment at a suitable temperature.

When the obtained polarizing plate is bonded to a display device such as liquid crystal or organic electroluminescence, various functional layers and luminance for improving the viewing angle and / or contrast on the surface of the protective layer or film that will be the non-exposed surface later. An improving layer or film can also be provided. It is preferable to use a pressure-sensitive adhesive for bonding the polarizing plate and the film to a display device.

The polarizing plate may have various known functional layers such as an antireflection layer, an antiglare layer, and a hard coat layer on the other surface, that is, the exposed surface of the protective layer or film. A coating method is preferable for producing the layer having various functions, but a film having the function can be bonded through an adhesive or a pressure-sensitive adhesive. The various functional layers can be a layer or a film for controlling the phase difference.

By the above method, a polarizing element comprising a hydrophilic polymer containing at least one dichroic dye in the present invention and silicon or a silicon compound, or a polarizing plate using the polarizing element can be obtained. I can do it. ADVANTAGE OF THE INVENTION According to this invention, durability with respect to the light and / or heat | fever of the polarizing element which consists of a hydrophilic polymer formed by adsorbing a dichroic dye, or a polarizing plate using the same can be improved, and burning can be improved. The display using the polarizing element or polarizing plate of the present invention is a display having high reliability, high contrast over the long term, and high color reproducibility.

When the polarizing plate of the present invention thus obtained is used for a blue light source of a liquid crystal projector, for example, the burning phenomenon is greatly reduced. At this time, the wavelength of the polarizing plate required for the blue light source of the liquid crystal projector is generally 400 to 500 nm, and it is particularly necessary to have a high degree of polarization at a wavelength of 430 to 500 nm. For example, at a wavelength of 430 to 500 nm, the transmittance is 0.3% or less when irradiated with linearly polarized light parallel to the absorption axis of the polarizing element, and when irradiated with linearly polarized light orthogonal to the absorption axis of the polarizing element. It is preferable that the polarizing plate has an optical characteristic of 77% or more, and more preferably, the transmittance is 0.1% or less when irradiated with linearly polarized light parallel to the absorption axis of the polarizing element. It is preferable that the polarizing plate has an optical characteristic of 80% or more when irradiated with linearly polarized light orthogonal to the absorption axis.

Furthermore, when the polarizing plate of the present invention is used for, for example, a green light source of a liquid crystal projector, the burning phenomenon can be similarly suppressed. At this time, the wavelength of the polarizing plate required for the green light source of the liquid crystal projector is 500 to 600 nm, and particularly needs to have a high degree of polarization at a wavelength of 520 to 580 nm. At 520 to 580 nm, the transmittance is 0.2% or less when irradiated with linearly polarized light parallel to the absorption axis of the polarizing element, and 83% when irradiated with linearly polarized light orthogonal to the absorption axis of the polarizing element. It is preferable that the polarizing plate has the above optical characteristics, and more preferably, the transmittance is 0.1% or less when irradiated with linearly polarized light parallel to the absorption axis of the polarizing element, and the absorption axis of the polarizing element. A polarizing plate having an optical characteristic of 86% or more when irradiated with linearly polarized light orthogonal to is preferable.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto. In addition, the transmittance | permeability shown in an Example was performed as follows.

When measuring the transmittance using a spectrophotometer [“U-4100” manufactured by Hitachi, Ltd.], the transmittance after correcting the visibility based on JIS-Z8701 (C light source 2 ° field of view) on the light exit side. An iodine polarizing plate (SKN-18043P manufactured by Polatechno Co., Ltd.) having a polarization degree of 99.99% at 43% was installed so that absolute polarized light could be incident on the measurement sample. In this case, the protective layer of the iodine-based polarizing plate is triacetyl cellulose having no ultraviolet absorbing ability.

Absolutely polarized light is incident on a polarizing plate obtained by laminating a protective film on one side of the polarizing plate of the present invention so that the vibration direction of the absolute polarized light is parallel to the absorption axis direction of the polarizing plate of the present invention. The absolute parallel transmittance obtained by measuring Kz, and the absolute perpendicular transmittance obtained by measuring the vibration direction of the absolutely polarized light and the absorption axis direction of the polarizing plate of the present invention are orthogonal. Ky.

Each transmittance was measured using a spectrophotometer [“U-4100” manufactured by Hitachi, Ltd.].

Example 1
<Preparation of aqueous solution containing hydrolyzed silane coupling agent>
While stirring, N-β- (aminoethyl) γ-aminopropyltrimethoxysilane (KBM-603, manufactured by Shin-Etsu Chemical Co., Ltd.) was gradually added to distilled water at room temperature to 1 wt%. After addition of the whole amount, stirring was continued for 30 minutes to obtain an aqueous solution containing a hydrolyzed silane coupling agent.

<Preparation of polarizing element obtained by treating silane coupling agent>
A polyvinyl alcohol resin film (VF series, manufactured by Kuraray Co., Ltd.) having a saponification degree of 99% or more and a film thickness of 75 μm was immersed in warm water at 40 ° C. for 2 minutes for swelling treatment. 45 ° C. containing 0.1% by weight of C-I Direct Orange 39, 0.05% by weight of C-I Direct Red 81, and 0.1% by weight of sodium tripolyphosphate as an azo dye. The sample was immersed in an aqueous solution to adsorb the dye. The film on which the dye was adsorbed was washed with water. After washing, the film was treated with boric acid for 1 minute with a 40 ° C. aqueous solution containing 2% by weight of boric acid. The film obtained by the boric acid treatment was treated for 5 minutes in an aqueous solution at 55 ° C. containing 3.0% by weight of boric acid while stretching 5.0 times. The film obtained by the boric acid treatment was treated with an aqueous solution containing 1% by weight of hydrolyzed silane coupling agent KBM-603 at 30 ° C. for 15 seconds while maintaining the tension state of the film. The film obtained by the treatment was immediately dried at 60 ° C. for 5 minutes to obtain a polarizing element having a thickness of 28 μm. When the content of silicon atoms in the obtained polarizing element was measured with an SPS3100 ICP emission spectroscopic analyzer (manufactured by SII Nanotechnology), a silicon content of 678 ppm was confirmed. A triacetyl cellulose film (TD-80U, manufactured by Fuji Photo Film Co., Ltd., hereinafter abbreviated as TAC) having a film thickness of 80 μm obtained by subjecting the obtained polarizing element to an alkali treatment using a polyvinyl alcohol adhesive, TAC / adhesive layer / polarizing element / A polarizing plate was obtained by laminating with an adhesive layer / TAC structure and laminating. 1 and 2 show the absolute parallel transmittance Ky and the absolute orthogonal transmittance Kz of the polarizing plate obtained.

The obtained polarizing plate was cut into 40 mm × 40 mm, and TAC / adhesive layer / polarizing element / adhesive layer / TAC / adhesive layer / transparent glass on a 1 mm transparent glass plate via an adhesive PTR-3000 (manufactured by Nippon Kayaku Co., Ltd.) A measurement sample was obtained by pasting together in the configuration of a plate.

Using the prepared sample, a test for 735 hours was performed in an environment of 85 ° C. with a high-pressure mercury lamp light resistance tester (Ushio Electric Co., Ltd., ultra-high pressure mercury lamp 2000 W). The irradiation light was installed so as to be incident from the TAC surface and tested. Ky was measured at 430 nm and 450 nm before and after the test.

Example 2
In Example 1, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane (KBM-603 manufactured by Shin-Etsu Chemical Co., Ltd.) and γ-aminopropyltrimethoxysilane (KBM manufactured by Shin-Etsu Chemical Co., Ltd.) were used as silane coupling agents. A polarizing plate was produced in the same manner except that a polarizing element was produced in place of -903), and a high-pressure mercury lamp light resistance tester was conducted. When the content of silicon atoms in the obtained polarizing element was measured by ICP emission analysis, a silicon content of 484 ppm was confirmed.

Comparative Example 1
In Example 1, a polarizing plate was prepared in the same manner except that N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane (KBM-603 manufactured by Shin-Etsu Chemical Co., Ltd.) was not used as the silane coupling agent. Then, a high-pressure mercury lamp light resistance tester was conducted. When the content of silicon atoms in the obtained polarizing element was measured by ICP emission analysis, the silicon content was not confirmed.

Table 1 shows the results of measuring Ky at 430 nm and 450 nm obtained by the high-pressure mercury lamp light resistance test of Example 1, Example 2, and Comparative Example 1, and the amount of change.

As can be seen from Examples 1 and 2 and Comparative Example 1, the film obtained by treatment with the silane coupling agent has little change in transmittance from the initial stage of the polarizing plate at 430 nm and 450 nm. Or, durability against heat can be improved, and burning can be improved.

Example 3
In Example 1, as an environmental acceleration test, a polarizing plate was produced in the same manner except that a heat resistance test at 140 ° C. for 288 hours was performed, and an environmental acceleration test was performed. Before and after applying the environmental acceleration test, the average transmittance Kave was measured at a measured value of Ky every 5 nm from 430 to 500 nm.

Example 4
In Example 3, an environmental acceleration test was conducted in the same manner except that N-β- (aminoethyl) -γ-aminopropylmethyldimethoxysilane (KBM-602 manufactured by Shin-Etsu Chemical Co., Ltd.) was used as the silane coupling agent. It was. Before and after applying the environmental acceleration test, an average transmittance (hereinafter referred to as “Kave”) was measured at a measured value of Ky every 5 nm from 430 to 500 nm.

Example 5
A polarizing plate was prepared in the same manner as in Example 3 except that γ-glycidoxypropyltrimethoxysilane (KBM-403 manufactured by Shin-Etsu Chemical Co., Ltd.) was used as the silane coupling agent, and an environmental acceleration test was performed. Kave was measured before and after applying the environmental acceleration test.

Example 6
In Example 1, treatment was performed at 30 ° C. for 15 seconds with an aqueous solution containing 1% by weight of hydrolyzed silane coupling agent KBM-603. A polarizing plate was prepared in the same manner except that the film obtained by the treatment was immediately heat treated at 80 ° C. for 5 minutes, and an environmental acceleration test was performed. Kave was measured before and after applying the environmental acceleration test.

Comparative Example 2
In Example 3, a polarizing plate was prepared in the same manner except that no silane coupling agent was used, and an environmental acceleration test was performed. Kave was measured before and after applying the environmental acceleration test.

Table 2 shows the results of measuring Kave obtained by the 140 ° C. heat resistance test in Examples 3 to 6 and Comparative Example 2, and the amount of change.

As can be seen from Examples 3 to 6 and Comparative Example 2, the polarizing element or polarizing plate of the present invention obtained by treating with a silane coupling agent has a change amount of Kave in the heat resistance test at 140 ° C. In comparison, the change is a little more than 11%, and the heat resistance is improved.

As is clear from the above Examples and Comparative Examples, a polarizing element comprising at least one dichroic dye of the present invention and a hydrophilic polymer containing silicon or a silicon compound was used. It can be seen that the polarizing plate characterized by this has little change in transmittance even in a light resistance test having an intensity of light like an ultra-high pressure mercury lamp, and little change in transmittance also in a heat resistance test. This indicates that the durability against light and / or heat can be improved and the burning can be improved, and it is very effective for suppressing the deterioration by decreasing the transmittance and increasing the light absorption. It is valid. The liquid crystal projector using the polarizing element and polarizing plate of the present invention can maintain stable performance even when used for a long time.

The polarizing element of the present invention can be used for polarizing plates such as liquid crystal projectors.

The absolute parallel transmittance Ky of the polarizing plate obtained in Example 1 is shown. The absolute direct transmittance Kz of the polarizing plate obtained in Example 1 is shown.

Claims

A polarizing element comprising a hydrophilic polymer containing at least one dichroic dye and silicon or a silicon compound.
The polarizing element according to claim 1, wherein the dichroic dye is an azo dye.
The polarizing element according to claim 1, wherein the silicon compound is a silane coupling agent.
The polarizing element according to claim 3, wherein the silane coupling agent contains an amino group.
The polarizing element according to claim 1, wherein the hydrophilic polymer is made of a polyvinyl alcohol-based resin film and is stretched.
A polarizing plate comprising the polarizing element according to claim 1, wherein a protective layer is provided on one side or both sides of the polarizing element.
The polarizing plate according to claim 6, which is for a liquid crystal projector.
The polarizing plate according to claim 7, which is for a blue light source.
A liquid crystal display device provided with the polarizing element according to claim 1 or a polarizing plate.
A liquid crystal projector provided with the polarizing element according to claim 1 or a polarizing plate.
6. The hydrophilic polymer containing at least one dichroic dye is treated with a solution containing silicon or a silicon compound, and then immediately dried. Manufacturing method of polarizing element.