WO2019131218A1 - Polarizing plate with adhesive layer - Google Patents

Abstract

The present invention provides a polarizing plate with an adhesive layer, which is thin and has extremely excellent moisture resistance. A polarizing plate with an adhesive layer according to the present invention comprises: a polarizer; a protective film which is arranged on one surface of the polarizer; and an adhesive layer which is arranged on the other surface of the polarizer. The polarizer has an iodine content of from 10% by weight to 25% by weight; the adhesive layer contains a conductive agent; and the conductive agent contains an inorganic cation salt.

Description

Pressure sensitive adhesive layer-attached polarizing plate

The present invention relates to a polarizing plate with a pressure-sensitive adhesive layer.

In a liquid crystal display device, which is a typical image display device, polarizers (substantially, polarizers including a polarizer) are disposed on both sides of a liquid crystal cell due to the image forming system. A polarizer is typically manufactured by dyeing a polyvinyl alcohol (PVA) based resin film with a dichroic substance such as iodine. In recent years, the demand for thinning of the image display apparatus has been increasing. Therefore, further thinning is required also for the polarizer. However, as the polarizer becomes thinner, there is a problem of moisture resistance that the optical characteristics are apt to be easily deteriorated in a high temperature and high humidity environment.

JP 2012-247574 A JP, 2017-102476, A JP, 2015-094906, A JP, 2015-094907, A

The present invention has been made to solve the above-mentioned problems, and its main object is to provide a pressure-sensitive adhesive layer-attached polarizing plate which is thin and has excellent moisture resistance.

The pressure-sensitive adhesive layer-attached polarizing plate of the present invention has a polarizer, a protective film disposed on one side of the polarizer, and a pressure-sensitive adhesive layer disposed on the other side of the polarizer. The iodine content of the polarizer is 10% by weight to 25% by weight, the pressure-sensitive adhesive layer contains a conductive agent, and the conductive agent contains an inorganic cationic salt.
In one embodiment, the inorganic cation salt is a lithium salt.
In one embodiment, the anion constituting the anion part of the inorganic cation salt is represented by the following general formulas (1) to (4)
(1): (C _n F _{2 n + 1} SO ₂ ) ₂ N ⁻ (n is an integer of 1 to 10),
(2): CF ₂ (C _m F _{2 m} SO ₂ ) ₂ N ⁻ (m is an integer of 1 to 10),
^{_{(3): - O 3 S}} (CF 2) l SO 3 - (l is an integer of from 1 to 10),
^{_{(4) :( C p F 2p}} + 1 SO 2) N - (C q F 2q + 1 SO 2), (p, q is an integer of 1 to 10),
It is selected from the anion represented by
In one embodiment, the content of the inorganic cation salt is 0.01 parts by weight to 5 parts by weight with respect to 100 parts by weight of the base polymer of the pressure-sensitive adhesive layer.
In one embodiment, the conductive agent further comprises an organic cationic salt.
In one embodiment, the content of the organic cationic salt is 0.1 parts by weight to 10 parts by weight with respect to 100 parts by weight of the base polymer of the pressure-sensitive adhesive layer.
In one embodiment, the thickness of the polarizer is 3 μm or less.

According to the present invention, by introducing a conductive agent containing an inorganic cation salt (preferably, a lithium salt) into the pressure-sensitive adhesive layer, it is extremely excellent despite the use of a thin polarizer having a very high iodine content. Moisture resistance can be realized.

It is a schematic sectional drawing explaining the polarizing plate with an adhesive layer by one Embodiment of this invention.

Hereinafter, although the embodiment of the present invention is described, the present invention is not limited to these embodiments.

A. Outline of Pressure-Sensitive Adhesive Layer-Coated Polarizer FIG. 1 is a schematic cross-sectional view of a pressure-sensitive adhesive layer-attached polarizing plate according to an embodiment of the present invention. The pressure-sensitive adhesive layer-attached polarizing plate 100 of the illustrated example comprises a polarizer 10, a protective film 20 disposed on one side of the polarizer 10, and an adhesive layer 30 disposed on the other side of the polarizer. Have. The pressure-sensitive adhesive layer 30 is typically the outermost layer on the image display device side. In an embodiment of the present invention, the iodine content of the polarizer is 10% to 25% by weight. Furthermore, the pressure-sensitive adhesive layer contains a conductive agent, and the conductive agent contains an inorganic cation salt.

Practically, a separator (not shown) is releasably and temporarily attached to the pressure-sensitive adhesive layer 30, thereby protecting the pressure-sensitive adhesive layer until actual use and enabling roll formation. Another protective film (not shown) may be disposed between the polarizer 10 and the pressure-sensitive adhesive layer 30 as needed. Furthermore, if necessary, a retardation film (not shown) may be disposed between the polarizer 10 and the pressure-sensitive adhesive layer 30 or outside the protective film 20. Optical properties of retardation film (for example, refractive index ellipsoid, in-plane retardation, thickness retardation, Nz coefficient, wavelength dispersion characteristics), number of sheets, combination, angle between slow axis and absorption axis of polarizer, etc. May be set appropriately according to the purpose.

Hereinafter, the polarizer, the protective film, and the pressure-sensitive adhesive layer constituting the pressure-sensitive adhesive layer-attached polarizing plate will be specifically described.

B. Polarizer B-1. Configuration and Properties of Polarizer The polarizer is typically composed of a polyvinyl alcohol (PVA) resin film. Examples of the PVA-based resin forming the PVA-based resin film include polyvinyl alcohol and ethylene-vinyl alcohol copolymer. Polyvinyl alcohol is obtained by saponifying polyvinyl acetate. The ethylene-vinyl alcohol copolymer is obtained by saponifying an ethylene-vinyl acetate copolymer. The saponification degree of the PVA-based resin is usually 85 mol% or more and less than 100 mol%, preferably 95.0 mol% to 99.95 mol%, more preferably 99.0 mol% to 99.93 mol%. is there. The degree of saponification can be determined according to JIS K 6726-1994. By using a PVA resin having such a degree of saponification, a polarizer excellent in durability can be obtained. If the degree of saponification is too high, gelation may occur.

The average degree of polymerization of the PVA-based resin can be appropriately selected depending on the purpose. The average degree of polymerization is usually 1000 to 10000, preferably 1200 to 4500, and more preferably 1500 to 4300. The average degree of polymerization can be determined according to JIS K 6726-1994.

In one embodiment, the PVA-based resin film may be a PVA-based resin layer formed on a substrate. The laminate of the substrate and the PVA-based resin layer can be obtained, for example, by a method of applying a coating solution containing the above-mentioned PVA-based resin to a substrate, a method of laminating a PVA-based resin film on a substrate, or the like.

The iodine content of the polarizer can be appropriately set to achieve sufficient polarization performance and optimum single transmittance. The iodine content is 10% to 25% by weight as described above, preferably 15% to 25% by weight. According to an embodiment of the present invention, in a polarizing plate including a polarizer having such an extremely high iodine content, by adopting a specific pressure-sensitive adhesive layer to be described later, it is extremely excellent conventionally difficult. Moisture resistance can be realized. More specifically, in a polarizing plate including a polarizer having an extremely high iodine content, it is possible to significantly suppress a single transmittance change, a polarization degree change, and a hue change under a high temperature and high humidity environment. In the present specification, the "iodine content" means the amount of all iodine contained in a polarizer (PVA-based resin film). More specifically, iodine during polarizers iodide ion (I ^-), molecular iodine (I _2), polyiodine ion _{^{(I 3 -, I 5 -}} ) where present in the form of such, herein The iodine content means the amount of iodine including all of these forms. The iodine content can be calculated, for example, by a calibration curve method of fluorescent X-ray analysis. The polyiodine ion is present in the form of a PVA-iodine complex in the polarizer. By forming such a complex, absorption dichroism can be exhibited in the wavelength range of visible light. Specifically, a complex of PVA and tri-iodide ion (PVA · _{I 3} ^-) has a light absorption peak around 470 nm, a complex of PVA and five iodide ion (PVA · _{I 5} ^-) is 600nm near Have an absorption peak. As a result, polyiodine ion can absorb light in a wide range of visible light depending on its form. On the other hand, an iodine ion (I ^-) has an absorption peak around 230 nm, not involved in substantially the absorption of visible light. Therefore, polyiodine ions present in the form of a complex with PVA can be mainly responsible for the absorption performance of the polarizer.

The upper limit of the thickness of the polarizer is 5 μm in one embodiment, 3 μm in another embodiment, and 2 μm in still another embodiment. The lower limit of the thickness is 0.5 μm in one embodiment, 0.6 μm in another embodiment, 0.8 μm in still another embodiment, and 1 μm in still another embodiment. And in another embodiment 2 μm. According to the embodiment of the present invention, desired single transmittance and polarization degree can be realized even with a thin polarizer.

The single transmittance (Ts) of the polarizer is preferably 30.0% to 43.0%, and more preferably 35.0% to 41.0%. The degree of polarization of the polarizer is preferably 99.9% or more, more preferably 99.95% or more, and still more preferably 99.98% or more. By setting the single transmittance low and increasing the degree of polarization, the contrast can be increased, and the black display can be displayed more black, so that an image display apparatus with excellent image quality can be realized. The single transmittance is a value measured by a spectrophotometer equipped with an integrating sphere. The single transmittance is a Y value measured with a 2 degree visual field (C light source) according to JIS Z8701 and subjected to visibility correction. For example, an ultraviolet-visible spectrophotometer with an integrating sphere (manufactured by JASCO Corporation, product name: V7100) can be used to measure.

In the embodiment of the present invention, although the iodine content of the polarizer is extremely high as described above, the change in optical characteristics under a high temperature and high humidity environment is significantly suppressed as described later in the examples. There is. In addition, color change under high temperature and high humidity environment is also suppressed. Such excellent effects can be realized by using the pressure-sensitive adhesive layer in which the conductive agent containing the above-mentioned inorganic cation salt is introduced in combination with the above-mentioned polarizer. More specifically, such an excellent effect is that the iodine complex is stabilized by binding of the inorganic cation (for example, lithium ion) derived from the conductive agent in the adhesive layer to the iodine complex in the polarizer, and as a result, It is estimated that this is realized by suppressing the reduction of iodine (especially polyiodine ions such as I ₃ ⁻ and I ₅ ⁻ ) under high temperature and high humidity environment. This solves a newly found problem by actually producing a very thin (for example, 3 μm thick or less) polarizer which was conventionally difficult to produce, and is unexpectedly superior It is an effect.

B-2. Method of Producing Polarizer B-2-1. Outline of Production Method A polarizer can be produced by a production method including at least drawing and dyeing of a PVA-based resin film. Typically, the manufacturing method includes a step of preparing a PVA-based resin film, a drawing step, a swelling step, a dyeing step, a crosslinking step, a washing step, and a drying step. Each step in which the PVA-based resin film is provided may be performed in any appropriate order and timing. Thus, the steps may be performed in the order described above, or in an order different from that described above. If necessary, one step may be performed multiple times. Furthermore, steps other than the above (for example, insolubilization step) may be performed at any appropriate timing. In addition, when a PVA-type resin film is a PVA-type resin layer formed on the base material, the laminated body of a base material and a PVA-type resin layer is provided to said process.

Hereinafter, although each process is demonstrated, each process may be performed in arbitrary appropriate order as mentioned above, and it is not limited to a description order.

B-2-2. Stretching Step In the stretching step, the PVA-based resin film is uniaxially stretched, typically 3 to 7 times. The stretching direction may be the longitudinal direction of the film (MD direction) or the width direction of the film (TD direction). The stretching method may be dry stretching, wet stretching, or a combination thereof. Moreover, when performing a bridge | crosslinking process, a swelling process, a dyeing process, etc., you may extend | stretch a PVA-type resin film. The stretching direction may correspond to the absorption axis direction of the obtained polarizer.

B-2-3. Swelling step The swelling step is usually performed before the dyeing step. The swelling step is performed, for example, by immersing the PVA-based resin film in a swelling bath. As the swelling bath, water such as distilled water or pure water is usually used. The swelling bath may comprise any suitable other component besides water. Other components include solvents such as alcohols, additives such as surfactants, and iodides. Examples of the iodide include potassium iodide, lithium iodide, sodium iodide, zinc iodide, aluminum iodide, lead iodide, copper iodide, barium iodide, calcium iodide, tin iodide and titanium iodide. Etc. Preferably, potassium iodide is used. The temperature of the swelling bath is, for example, 20 ° C to 45 ° C. The immersion time is, for example, 10 seconds to 300 seconds.

B-2-4. Dyeing Step The dyeing step is a step of dyeing a PVA-based resin film with a dichroic substance. Preferably, it is carried out by adsorbing a dichroic substance. As the adsorption method, for example, a method of immersing a PVA-based resin film in a dyeing liquid containing a dichroic substance, a method of applying the dyeing liquid to a PVA-based resin film, and spraying the dyeing liquid onto a PVA-based resin film And the like. Preferably, it is a method of immersing a PVA-based resin film in a staining solution. It is because a dichroic substance can be adsorbed well.

As said dichroic substance, iodine and a dichroic dye are mentioned, for example. Preferably, it is iodine. When iodine is used as the dichroic substance, an aqueous iodine solution is preferably used as the staining solution. The content of iodine in the aqueous iodine solution is preferably 0.04 parts by weight to 5.0 parts by weight with respect to 100 parts by weight of water. In order to enhance the solubility of iodine in water, it is preferable to add an iodide to an aqueous iodine solution. As iodide, potassium iodide is preferably used. The content of iodide is preferably 0.3 to 15 parts by weight with respect to 100 parts by weight of water.

The liquid temperature at the time of staining of the staining solution can be set to any appropriate value, and is, for example, 20 ° C. to 50 ° C. When immersing the PVA-based resin film in the staining solution, the immersion time is, for example, 5 seconds to 5 minutes.

B-2-5. Crosslinking Step In the crosslinking step, a boron compound is usually used as a crosslinking agent. Examples of boron compounds include boric acid and borax. Preferably, it is boric acid. In the crosslinking step, the boron compound is usually used in the form of an aqueous solution.

When an aqueous boric acid solution is used, the boric acid concentration of the aqueous boric acid solution is, for example, 1% by weight to 15% by weight, preferably 1% by weight to 10% by weight. The boric acid aqueous solution may further contain an iodide such as potassium iodide and a zinc compound such as zinc sulfate and zinc chloride.

The crosslinking step can be performed by any suitable method. For example, a method of immersing a PVA-based resin film in an aqueous solution containing a boron compound, a method of applying an aqueous solution containing a boron compound to a PVA-based resin film, or a method of spraying an aqueous solution containing a boron compound onto a PVA-based resin film Be It is preferable to immerse in an aqueous solution containing a boron compound.

The temperature of the solution used for crosslinking is, for example, 25 ° C. or higher, preferably 30 ° C. to 85 ° C., and more preferably 40 ° C. to 70 ° C. The immersion time is, for example, 5 seconds to 800 seconds, preferably 8 seconds to 500 seconds.

B-2-6. Washing Step The washing step can typically be performed after the crosslinking step. The washing step is typically performed by immersing the PVA-based resin film in a washing solution. Pure water can be mentioned as a representative example of the cleaning liquid. Potassium iodide may be added to pure water.

The temperature of the cleaning solution is, for example, 5 ° C to 50 ° C. The immersion time is, for example, 1 second to 300 seconds.

B-2-7. Drying Step The drying step can be performed by any appropriate method. As a drying method, natural drying, ventilation drying, reduced-pressure drying, heat-drying etc. are mentioned, for example. Heat drying is preferably used. When heat drying is performed, the heating temperature is, for example, 30 ° C. to 100 ° C. The drying time is, for example, 20 seconds to 10 minutes.

C. Protective Film Any suitable resin film is used as the protective film (and, if present, another protective film). As a material for forming the resin film, for example, cellulose resins such as (meth) acrylic resins, diacetyl cellulose and triacetyl cellulose, cycloolefin resins such as norbornene resins, olefin resins such as polypropylene, polyethylene terephthalate resins And ester resins, polyamide resins, polycarbonate resins, copolymer resins thereof, and the like. In addition, "(meth) acrylic-type resin" means acrylic resin and / or methacrylic resin.

In one embodiment, a (meth) acrylic resin having a glutarimide structure is used as the (meth) acrylic resin. Examples of (meth) acrylic resins having a glutarimide structure (hereinafter, also referred to as glutarimide resins) include, for example, JP-A-2006-309033, JP-A-2006-317560, and JP-A-2006-328329, and JP-A-2006-328329. 2006-328334, JP-A 2006-337491, JP-A 2006-337492, JP-A 2006-337493, JP-A 2006-337569, JP-2007-009182, JP-2009- No. 161744 and Japanese Patent Application Laid-Open No. 2010-284840. These descriptions are incorporated herein by reference.

When manufacturing a polarizer using the laminated body of a base material and a PVA-type resin layer, you may use it as a protective film as it is, without peeling a base material. Alternatively, the substrate may be peeled off and the polarizer may be bonded to the protective film.

Depending on the purpose, any suitable optically functional film may be used as a protective film (and, if present, another protective film). Examples of the optical functional film include a retardation film and a reflective polarizer (brightness improving film).

D. Pressure-Sensitive Adhesive Layer In the pressure-sensitive adhesive layer-attached polarizing plate according to the embodiment of the present invention, as described above, the protective film is disposed on one side of the polarizer, and the pressure-sensitive adhesive layer is disposed on the other side of the polarizer. It is done. That is, in this embodiment, the pressure-sensitive adhesive layer is directly disposed on the polarizer without disposing the protective film on the other side of the polarizer.

D-1. Pressure-Sensitive Adhesive Composition The pressure-sensitive adhesive composition constituting the pressure-sensitive adhesive layer contains a base polymer and a conductive agent.

D-1-1. Base Polymers Representative examples of base polymers include (meth) acrylic polymers ((meth) acrylic resins). The (meth) acrylic polymer typically contains, as a main component, a monomer unit derived from an alkyl (meth) acrylate. The alkyl (meth) acrylate is an alkyl ester of (meth) acrylic acid. Examples of the alkyl group forming the alkyl ester include a linear or branched alkyl group having 1 to 18 carbon atoms. Specific examples of the alkyl group include methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, amyl group, hexyl group, cyclohexyl group, heptyl group, 2-ethylhexyl group, isooctyl group, nonyl group, decyl Groups, isodecyl group, dodecyl group, isomyristyl group, lauryl group, tridecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group. These may be used alone or in combination. The average carbon number of the alkyl group contained in the (meth) acrylic polymer is preferably 3 to 9.

The base polymer may contain monomer units derived from any suitable copolymerization component depending on the purpose. As a copolymerization component, for example, a hydroxyl group-containing monomer, a carboxyl group-containing monomer, an acid anhydride group-containing monomer, a sulfonic acid group-containing monomer, a phosphoric acid group-containing monomer, (N-substituted) amide-based monomer, (meth) acrylic Acid alkyl amino alkyl type monomer, (meth) acrylic acid alkoxy alkyl type monomer, succinimide type monomer, maleimide type monomer, itacon imide type monomer, vinyl type monomer, cyano (meth) acrylate type monomer, epoxy group containing (meth) acrylic type monomer And glycol-based (meth) acrylic ester monomers, silane-based monomers, and polyfunctional monomers. By adjusting the type, number, combination, and copolymerization ratio (weight ratio) of the copolymerization components, it is possible to obtain a base polymer (finally, a pressure-sensitive adhesive layer) having desired properties. The proportion of the copolymerization component in all the monomer components is preferably 0 wt% to 20 wt%, more preferably 0.1 wt% to 15 wt%, still more preferably 0.1 wt%, relative to 100 wt% of all the monomer components. % To 10% by weight.

The weight average molecular weight of the base polymer is typically 500,000 to 3,000,000, preferably 700,000 to 2,700,000, and more preferably 800,000 to 2,500,000. If the weight average molecular weight is too small, heat resistance may be insufficient. When the weight average molecular weight is too large, the handling property may be deteriorated, and a large amount of dilution solvent may be required for viscosity adjustment for coating, which may increase the cost. The weight average molecular weight is a value measured by GPC (gel permeation chromatography) and calculated by polystyrene conversion.

D-1-2. Conducting Agent The conducting agent comprises an inorganic cationic salt as described above. The inorganic cation salt is specifically an inorganic cation-anion salt. As a cation which comprises the cation part of inorganic cation salt, an alkali metal ion is mentioned typically. Specific examples include lithium ion, sodium ion and potassium ion. Preferably, it is lithium ion. Thus, the preferred inorganic cation salt is a lithium salt.

Examples of the anion constituting the anion portion of the inorganic cation salts, for _{^{example, Cl -, Br -, I}} -, AlCl 4 -, Al 2 Cl 7 -, BF 4 -, PF 6 -, ClO 4 -, NO 3 -, CH ₃ COO ⁻ , CF ₃ COO ⁻ , CH ₃ SO ₃ ⁻ , CF ₃ SO ₃ ⁻ , (CF ₃ SO ₂ ) ₃ C ⁻ , AsF ₆ ⁻ , SbF ₆ ⁻ , NbF ₆ ⁻ , TaF ₆ ⁻ , (CN _{^{) 2 N -, C 4 F}} 9 SO 3 -, C 3 F 7 COO -, (CF 3 SO 2) (CF 3 CO) N -, - O 3 S (CF 2) 3 SO 3 -, and, below General Formulas (1) to (4)
(1): (C _n F _{2 n + 1} SO ₂ ) ₂ N ⁻ (n is an integer of 1 to 10),
(2): CF ₂ (C _m F _{2 m} SO ₂ ) ₂ N ⁻ (m is an integer of 1 to 10),
_{^{(3): - O 3 S}} (CF 2) l SO 3 - (l is an integer of from 1 to 10),
^{_{(4) :( C p F 2p}} + 1 SO 2) N - (C q F 2q + 1 SO 2), (p, q is an integer of 1 to 10),
And the anion represented by The fluorine-containing anion is preferable, and the fluorine-containing imide anion is more preferable.

As a fluorine-containing imide anion, the imide anion which has a perfluoroalkyl group is mentioned, for example. Specific examples thereof include (CF ₃ SO ₂ ) (CF ₃ CO) N ⁻ described above, and general formulas (1), (2) and (4)
(1): (C _n F _{2 n + 1} SO ₂ ) ₂ N ⁻ (n is an integer of 1 to 10),
(2): CF ₂ (C _m F _{2 m} SO ₂ ) ₂ N ⁻ (m is an integer of 1 to 10),
^{_{(4) :( C p F 2p}} + 1 SO 2) N - (C q F 2q + 1 SO 2), (p, q is an integer of 1 to 10),
And the anion represented by Preferred are (perfluoroalkylsulfonyl) imides represented by the general formula (1) such as (CF ₃ SO ₂ ) ₂ N ⁻ , (C ₂ F ₅ SO ₂ ) ₂ N ^{− and the} like, more preferably (CF ₃ SO ₂ ) ₂ N ⁻ It is a bis (trifluoromethanesulfonyl) imide represented by SO ₂ ) ₂ N ^— . Thus, a preferred inorganic cationic salt that can be used in embodiments of the present invention is lithium bis (trifluoromethanesulfonyl) imide.

The content of the inorganic cation salt in the pressure-sensitive adhesive composition (as a result, the pressure-sensitive adhesive layer) is preferably 0.01 parts by weight to 5 parts by weight, more preferably 0.5 parts by weight with respect to 100 parts by weight of the base polymer. The amount is from 3 to 3 parts by weight, more preferably from 0.7 to 1.5 parts by weight. If the content of the inorganic cation salt is in such a range, the moisture resistance of a thin polarizer having a high iodine content (as a result, a polarizing plate including such a polarizer) can be significantly improved.

The conductive agent may further contain an organic cation salt, if necessary. By using an inorganic cation salt and an organic cation salt in combination, the surface resistance value can be further reduced without bleeding out the inorganic cation salt.

The organic cation salt is specifically an organic cation-anion salt. As a cation which comprises the cation part of organic cation salt, the organic onium which formed onium ion by substitution by an organic group typically is mentioned. Examples of the onium in the organic onium include nitrogen-containing onium, sulfur-containing onium, and phosphorus-containing onium. Preferred are nitrogen-containing onium and sulfur-containing onium. As the nitrogen-containing onium, ammonium cation, piperidinium cation, pyrrolidinium cation, pyridinium cation, cation having pyrroline skeleton, cation having pyrrole skeleton, imidazolium cation, tetrahydropyrimidinium cation, dihydropyrimidinium cation, A pyrazolium cation and a pyrazolinium cation can be mentioned. Preferred are ammonium cation, piperidinium cation and pyrrolidinium cation, and more preferred is pyrrolidinium cation. Examples of the sulfur-containing onium include sulfonium cations. As phosphorus-containing onium, a phosphonium cation is mentioned, for example. As an organic group in organic onium, an alkyl group, an alkoxyl group, an alkenyl group is mentioned, for example. Specific examples of preferred organic oniums include tetraalkyl ammonium cations, alkyl piperidinium cations, and alkyl pyrrolidinium cations. More preferably, it is ethyl methyl pyrrolidinium cation. The anion which comprises the anion part of the organic cation salt is as having demonstrated regarding the anion which comprises the anion part of inorganic cation. Thus, preferred organic cationic salts that can be used in embodiments of the present invention are pyrrolidinium salts, more preferably ethyl methyl pyrrolidinium bis (trifluoromethanesulfonyl) imide.

The content of the organic cation salt in the pressure-sensitive adhesive composition (as a result, the pressure-sensitive adhesive layer) is preferably 0.1 parts by weight to 10 parts by weight, more preferably 0.3 parts by weight with respect to 100 parts by weight of the base polymer. The amount is preferably 3 to 3 parts by weight, more preferably 0.5 to 1.5 parts by weight. If the content of the organic cation salt is in such a range, the effect of the combination of the organic cation salt and the inorganic cation salt becomes remarkable.

D-1-3. Silane Coupling Agent The pressure-sensitive adhesive composition may further contain a silane coupling agent. Durability can be improved by using a silane coupling agent. As a silane coupling agent, what has arbitrary appropriate functional groups can be used. Specifically, as a functional group, a vinyl group, an epoxy group, an amino group, a mercapto group, a (meth) acryloxy group, an acetoacetyl group, an isocyanate group, a styryl group, a polysulfide group etc. are mentioned, for example. Specifically, for example, vinyl group-containing silane coupling agents such as vinyltriethoxysilane, vinyltripropoxysilane, vinyltriisopropoxysilane, vinyltributoxysilane, etc .; γ-glycidoxypropyltrimethoxysilane, γ-gly Epoxy group-containing silane coupling agents such as cidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopropylmethyldimethoxysilane, N- (2-aminoethyl) 3-aminopropylmethyldimethoxysilane, γ-triethoxysilyl-N- (1,3-dimethylbutylidene) Propylamine, N-phenyl-γ Amino group-containing silane coupling agents such as aminopropyltrimethoxysilane; mercapto group-containing silane coupling agents such as γ-mercaptopropylmethyldimethoxysilane; styryl group-containing silane coupling agents such as p-styryltrimethoxysilane; γ- (Meth) acrylic group-containing silane coupling agents such as acryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane; isocyanate group-containing silane coupling agents such as 3-isocyanatopropyltriethoxysilane; bis (triethoxysilyl) And polysulfide group-containing silane coupling agents such as propyl) tetrasulfide.

D-1-4. Other The pressure-sensitive adhesive composition (as a result, the pressure-sensitive adhesive layer) may further contain any appropriate additive. Specific examples of the additive include a crosslinking agent, a silane coupling agent, a rework improver, an antioxidant, an antistatic agent, a crosslinking retarder, an emulsifier, a colorant, a powder such as a pigment, a dye, a surfactant, and a plastic Agents, tackifiers, surface lubricants, leveling agents, softeners, anti-aging agents, light stabilizers, UV absorbers, polymerization inhibitors, inorganic fillers, organic fillers, metal powders, particles, foils Can be mentioned. The number, type, addition amount, combination and the like of the additives may be appropriately set depending on the purpose.

Any appropriate method may be employed as a method of forming the pressure-sensitive adhesive layer. As a representative example of the formation method, a method of applying the above-mentioned pressure-sensitive adhesive composition to a release-treated separator or the like, drying and removing a polymerization solvent and the like to form a pressure-sensitive adhesive layer and transferring to a polarizer, or The method of apply | coating the said adhesive composition, drying removal of a polymerization solvent etc., and forming an adhesive layer in a polarizer is mentioned. In addition, in application | coating of an adhesive, you may newly add 1 or more types of solvents other than a polymerization solvent as needed.

The details of the pressure-sensitive adhesive composition are described, for example, in JP-A-2014-48497. The description of the publication is incorporated herein by reference.

D-2. Structure and Properties of Pressure-Sensitive Adhesive Layer The thickness of the pressure-sensitive adhesive layer is preferably 10 μm to 200 μm, and more preferably 10 μm to 100 μm. If the thickness of the pressure-sensitive adhesive layer is in such a range, the effect of improving the moisture resistance by the inorganic cation salt may be remarkable.

The surface resistance (initial) of the pressure-sensitive adhesive layer is preferably 5.0 × 10 ¹¹ Ω · □ or less, more preferably 1.0 × 10 ¹¹ Ω · □ or less, and still more preferably 5.0 × It is 10 ¹⁰ Ω · □ or less. The lower limit of the surface resistance value of the pressure-sensitive adhesive layer may be, for example, 5.0 × 10 ⁹ Ω · □. If the surface resistance value of the pressure-sensitive adhesive layer is in such a range, there is an advantage that electrostatic unevenness can be easily suppressed.

EXAMPLES Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited by these examples. The measuring method of each characteristic is as follows. In the examples, "parts" and "%" are based on weight unless otherwise specified.

(1) Iodine content About the polarizer of the polarizing plate with an adhesive layer obtained by the Example and the comparative example, a fluorescent-X-ray-analysis apparatus (The Rigaku Corporation make, brand name "ZSX-PRIMUS II", measurement diameter: 20 mm) The fluorescent X-ray intensity (kcps) was measured using On the other hand, the thickness (μm) of the polarizer was measured using a spectrofilm thickness meter (trade name “MCPD-3000” manufactured by Otsuka Electronics Co., Ltd.). The iodine content (% by weight) was determined from the obtained fluorescent X-ray intensity and thickness using the following equation.
(Iodine concentration) = 20.5 x (fluorescent X-ray intensity) / (film thickness)
In addition, although the coefficient at the time of calculating iodine content changes with measuring devices, the said coefficient can be calculated | required using a suitable calibration curve.
(2) Single transmittance change amount ΔTs
The polarizing plate with a pressure-sensitive adhesive layer obtained in Examples and Comparative Examples was bonded to an alkali-free glass having a thickness of 1.3 mm via the pressure-sensitive adhesive layer, and used as a test sample. The test sample was humidified at 65 ° C. and 90% RH for 500 hours (humidified test). The single-piece transmittance Ts ₀ before the test and the single-piece transmittance Ts ₅₀₀ after the humidification test were each measured using a UV-visible spectrophotometer with an integrating sphere (manufactured by JASCO Corporation, product name: V7100). From the single transmittance Ts ₀ before humidification and the single transmittance Ts ₅₀₀ after the humidification test, the single transmittance variation ΔTs was determined using the following equation.
ΔTs (%) = Ts ₅₀₀ -Ts ₀
(3) Degree of polarization change ΔP
About the polarizing plate with an adhesive layer obtained by the Example and the comparative example, the single transmittance Ts, the parallel transmittance Tp, and the single transmittance Ts using an integrating sphere-attached UV-visible spectrophotometer (manufactured by JASCO Corporation, product name: V7100) The orthogonal transmittance Tc was measured respectively. These Ts, Tp and Tc are Y values measured by the visual field (C light source) according to JIS Z 8701 and subjected to the visual sensitivity correction. The degree of polarization P was determined from the obtained Tp and Tc according to the following equation.
Degree of polarization P (%) = {(Tp-Tc) / (Tp + Tc)} ^1/2 × 100
Furthermore, the polarization degree change amount ΔP was determined using the following equation.
ΔP (%) = P ₅₀₀ -P ₀
Here, P ₀ is the degree of polarization before humidification, and P ₅₀₀ is the degree of polarization after being placed in an environment of 65 ° C. and 90% RH for 500 hours.
(4) Hue change Δab
The a value and the b value of the pressure-sensitive adhesive layer-attached polarizing plates obtained in Examples and Comparative Examples were measured using an integrating sphere-attached ultraviolet-visible spectrophotometer (V-7100, manufactured by JASCO Corporation). These were designated as a ₀ value and b ₀ value. Furthermore, the a ₅₀₀ value and the b ₅₀₀ value were determined after being humidified under the conditions of 65 ° C. and 90% RH for 500 hours. From these values, the hue change amount Δab was determined using the following equation.
Δab = {(a ₅₀₀ -a ₀ ) ² + (b ₅₀₀ -b ₀ ) ² } ^1/2
(5) Surface Resistance After peeling off the separator film of the polarizing plate with the pressure-sensitive adhesive layer obtained in Examples and Comparative Examples, the surface resistance (Ω · □) of the surface of the pressure-sensitive adhesive is measured by MCP- made by Mitsubishi Chemical Analytech Co., Ltd. It measured using HT450 (initial). Moreover, after humidifying the polarizing plate with an adhesive layer on condition of 65 degreeC and 90% RH for 48 hours, the surface resistance value of the adhesive surface was measured similarly (after a humidification test). In addition, the humidification test was done by throwing the polarizing plate with an adhesive layer into a constant temperature and humidity machine of 65 degreeC and 90% RH.

Example 1
(Preparation of Base Polymer of Pressure-Sensitive Adhesive Composition)
A monomer mixture containing 99 parts of butyl acrylate and 1 part of 4-hydroxybutyl acrylate was charged into a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a condenser. Furthermore, 0.1 part of 2,2'-azobisisobutyronitrile as a polymerization initiator is charged together with ethyl acetate to 100 parts of the above monomer mixture (solid content), and nitrogen gas is introduced while gently stirring. After purging with nitrogen, polymerization was carried out for 7 hours while maintaining the liquid temperature in the flask at about 60.degree. Thereafter, ethyl acetate was added to the obtained reaction solution to adjust the solid concentration to 30%. Thus, a solution of an acrylic polymer (A-1) (base polymer) having a weight average molecular weight of 1,400,000 was prepared.

(Preparation of pressure-sensitive adhesive composition)
1.0 part of lithium bis (trifluoromethanesulfonyl) imide (manufactured by Mitsubishi Materials Electronic Chemicals Co., Ltd.) and ethyl methyl pyrrolidinium bis (made by Mitsubishi Materials Electronic Chemicals Co., Ltd.) as a conductive agent relative to 100 parts of the solid content of the above acrylic polymer (A-1) solution Trifluoromethanesulfonyl) imide (manufactured by Tokyo Chemical Industry Co., Ltd.) 0.7 part, trimethylolpropane xylylene diisocyanate (Mitsui Chemical Co., Ltd .: Takenate D110N) 0.095 part as a crosslinking agent and 0.3 part of dibenzoyl peroxide, silane cup 0.2 parts of organosilane (Shonken Chemical Co., Ltd .: A100) and 0.2 parts of a thiol group-containing silane coupling agent (Shin-Etsu Chemical Co., Ltd .: X41-1810) as a ring agent, rework improver (Kaneka Co., Ltd., Syyl) SAT 10) 0.03 parts, and antioxidant (BASF Ltd., Irganox1010) 0.3 parts by blending, pressure-sensitive adhesive composition (solution) was prepared.

(Preparation of polarizing plate)
As a thermoplastic resin substrate, an amorphous isophthalic acid copolymerized polyethylene terephthalate (IPA copolymerized PET) film (thickness: 100 μm) having a water absorption coefficient of 0.75% and a Tg of 75 ° C. was used. One side of the substrate is subjected to corona treatment, and to this corona-treated side, polyvinyl alcohol (polymerization degree 4200, saponification degree 99.2 mol%) and acetoacetyl modified PVA (polymerization degree 1200, acetoacetyl modification degree 4.6) Aqueous solution containing 10%, degree of saponification of 99.0 mol% or more, manufactured by Japan Synthetic Chemical Industry Co., Ltd., trade name "Gosefamer Z200") at a ratio of 9: 1 at 25 ° C and dried to a thickness of 11 μm A PVA-based resin layer was formed to prepare a laminate.
The obtained laminate was stretched 4.5 times in air in a direction perpendicular to the longitudinal direction of the laminate at 140 ° C. using a tenter stretching machine (stretching treatment).
Then, the laminate was dipped in a dyeing bath (water solution with an iodine concentration of 1.4% by weight and a potassium iodide concentration of 9.8% by weight) at a liquid temperature of 25 ° C. for 12 seconds to stain (dye treatment).
Then, the laminate was immersed in a washing bath (pure water) having a liquid temperature of 25 ° C. for 6 seconds (first washing treatment).
Subsequently, the resultant was immersed for 16 seconds in a crosslinking bath (aqueous solution of 1 wt% of boron concentration and 1 wt% of potassium iodide) at 60 ° C. (crosslinking treatment).
Then, the laminate was immersed in a washing bath (aqueous solution of 1% by weight of potassium iodide) having a liquid temperature of 25 ° C. for 3 seconds (second washing treatment).
Then, the laminate was dried in an oven at 60 ° C. for 21 seconds (drying treatment).
Thus, a laminate (polarizing plate) having a 1.2 μm-thick PVA-based resin layer (polarizer) was obtained. The iodine content of the polarizer in the obtained polarizing plate was 20.9% by weight, and the single transmittance was 40.3%.

(Preparation of polarizing plate with pressure-sensitive adhesive layer)
The above pressure-sensitive adhesive composition is uniformly coated on the surface of a polyethylene terephthalate film (separator) treated with a silicone release agent with a fountain coater, and dried for 2 minutes in an air circulating constant temperature oven at 155 ° C. A pressure-sensitive adhesive layer having a thickness of 20 μm was formed. Then, the pressure-sensitive adhesive layer was transferred to the surface of the polarizer of the polarizing plate to obtain a polarizing plate with a pressure-sensitive adhesive layer.

The obtained polarizing plate with a pressure-sensitive adhesive layer was subjected to the evaluations of (2) to (5) above. The results are shown in Table 1.

Example 2
A pressure-sensitive adhesive composition was prepared in the same manner as in Example 1 except that only 0.2 part of A100 was used as a silane coupling agent. A pressure-sensitive adhesive layer-attached polarizing plate was obtained in the same manner as in Example 1 except that this pressure-sensitive adhesive composition was used. The obtained polarizing plate with a pressure-sensitive adhesive layer was subjected to the same evaluation as in Example 1. The results are shown in Table 1.

[Example 3]
A pressure-sensitive adhesive composition was prepared in the same manner as in Example 1 except that only 1.0 part of lithium bis (trifluoromethanesulfonyl) imide was used as a conductive agent. A pressure-sensitive adhesive layer-attached polarizing plate was obtained in the same manner as in Example 1 except that this pressure-sensitive adhesive composition was used. The obtained polarizing plate with a pressure-sensitive adhesive layer was subjected to the same evaluation as in Example 1. The results are shown in Table 1.

Example 4
A pressure-sensitive adhesive was prepared in the same manner as in Example 1, except that only 1.0 part of lithium bis (trifluoromethanesulfonyl) imide was used as the conductive agent, and only 0.2 part of A100 was used as the silane coupling agent. The composition was prepared. A pressure-sensitive adhesive layer-attached polarizing plate was obtained in the same manner as in Example 1 except that this pressure-sensitive adhesive composition was used. The obtained polarizing plate with a pressure-sensitive adhesive layer was subjected to the same evaluation as in Example 1. The results are shown in Table 1.

Comparative Example 1
A pressure-sensitive adhesive composition was prepared in the same manner as in Example 1 except that only 0.7 part of ethylmethylpyrrolidinium bis (trifluoromethanesulfonyl) imide was used as a conductive agent. A pressure-sensitive adhesive layer-attached polarizing plate was obtained in the same manner as in Example 1 except that this pressure-sensitive adhesive composition was used. The obtained polarizing plate with a pressure-sensitive adhesive layer was subjected to the same evaluation as in Example 1. The results are shown in Table 1.

Comparative Example 2
Same as Example 1 except that only 0.7 parts of ethyl methyl pyrrolidinium bis (trifluoromethanesulfonyl) imide was used as a conductive agent, and only 0.2 parts of A100 was used as a silane coupling agent The pressure-sensitive adhesive composition was prepared. A pressure-sensitive adhesive layer-attached polarizing plate was obtained in the same manner as in Example 1 except that this pressure-sensitive adhesive composition was used. The obtained polarizing plate with a pressure-sensitive adhesive layer was subjected to the same evaluation as in Example 1. The results are shown in Table 1.

Comparative Example 3
A pressure-sensitive adhesive composition was prepared in the same manner as in Example 1 except that the conductive agent was not used. A pressure-sensitive adhesive layer-attached polarizing plate was obtained in the same manner as in Example 1 except that this pressure-sensitive adhesive composition was used. The obtained polarizing plate with a pressure-sensitive adhesive layer was subjected to the same evaluation as in Example 1. The results are shown in Table 1.

As apparent from Table 1, the polarizing plate with the pressure-sensitive adhesive layer of the example of the present invention is excellent in any of the change in single transmittance, the change in polarization degree and the hue change after the humidification test. It turns out that it has sex.

The polarizer of the present invention can be widely applied to liquid crystal panels such as liquid crystal televisions, liquid crystal displays, mobile phones, digital cameras, video cameras, portable game machines, car navigation systems, copiers, printers, fax machines, watches, and microwave ovens. it can.

10 Polarizer 20 Protective Film 30 Adhesive Layer 100 Polarizer with Adhesive Layer

Claims (7)

1. A polarizer, a protective film disposed on one side of the polarizer, and an adhesive layer disposed on the other side of the polarizer;
   The iodine content of the polarizer is 10% by weight to 25% by weight,
   The pressure-sensitive adhesive layer contains a conductive agent,
   The conductive agent comprises an inorganic cation salt,
   Pressure sensitive adhesive layer-attached polarizing plate.
2. The pressure-sensitive adhesive layer-attached polarizing plate according to claim 1, wherein the inorganic cation salt is a lithium salt.
3. The anion which comprises the anion part of the said inorganic cation salt has following General formula (1)-(4)
   (1): (C _n F _{2 n + 1} SO ₂ ) ₂ N ⁻ (n is an integer of 1 to 10),
   (2): CF ₂ (C _m F _{2 m} SO ₂ ) ₂ N ⁻ (m is an integer of 1 to 10),
   ^{_{(3): - O 3 S}} (CF 2) l SO 3 - (l is an integer of from 1 to 10),
   ^{_{(4) :( C p F 2p}} + 1 SO 2) N - (C q F 2q + 1 SO 2), (p, q is an integer of 1 to 10),
   The pressure-sensitive adhesive layer-carrying polarizing plate according to claim 1 or 2, selected from the anions represented by
4. The pressure-sensitive adhesive layer according to any one of claims 1 to 3, wherein the content of the inorganic cation salt is 0.01 parts by weight to 5 parts by weight with respect to 100 parts by weight of the base polymer of the pressure-sensitive adhesive layer. Board.
5. The adhesive layer-attached polarizing plate according to any one of claims 1 to 4, wherein the conductive agent further contains an organic cation salt.
6. The pressure-sensitive adhesive layer-attached polarizing plate according to claim 5, wherein the content of the organic cation salt is 0.1 parts by weight to 10 parts by weight with respect to 100 parts by weight of the base polymer of the pressure-sensitive adhesive layer.
7. The polarizing plate with an adhesive layer in any one of Claims 1-6 whose thickness of the said polarizer is 3 micrometers or less.

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