CN106489086B

CN106489086B - Polarizer, polarizing plate with adhesive, and image display device

Info

Publication number: CN106489086B
Application number: CN201580031378.0A
Authority: CN
Inventors: 田崎诚; 村野耕太
Original assignee: Sumitomo Chemical Co Ltd
Current assignee: Sumitomo Chemical Co Ltd
Priority date: 2014-06-18
Filing date: 2015-06-16
Publication date: 2021-02-02
Anticipated expiration: 2035-06-16
Also published as: KR20170020452A; KR102347401B1; WO2015194523A1; JPWO2015194523A1; CN106489086A; TW201604261A; TWI662102B

Abstract

Even if an adhesive layer containing an antistatic agent is formed on at least one surface of a polarizing plate, discoloration or deterioration of the polarizing plate, which is likely to occur, can be suppressed when the polarizing plate is exposed to a high-temperature or high-humidity environment. The polarizing plate of the present invention has a pressure-sensitive adhesive layer formed on at least one surface thereof, the pressure-sensitive adhesive layer being formed from a pressure-sensitive adhesive composition containing an antistatic agent comprising a polyether and a salt having an anion having a fluoro group and a sulfonyl group. The polyether may be selected from at least 1 of 2 polyether esters having a specific structure, and polyalkylene glycol (di-or mono) alkyl ethers.

Description

Polarizer, polarizing plate with adhesive, and image display device

Technical Field

The present invention relates to a polarizing plate applied to an image display device such as a liquid crystal display device, an adhesive-equipped polarizing plate having a transparent protective layer on one surface of the polarizing plate and an adhesive layer on the other surface, and an image display device to which the adhesive-equipped polarizing plate is applied.

Background

In recent years, the use of liquid crystal display devices has been expanding rapidly, and these devices can be used from portable devices such as mobile phones to large-sized televisions regardless of the screen size. In addition to liquid crystal display devices, organic electroluminescence (organic EL) display devices are also increasing in the trend toward mobile applications. The polarizing plate used in these image display devices is not required to be increased in size, and is also required to have properties suitable for various uses.

The polarizing plate is generally bonded to an image display element such as a liquid crystal cell or an organic EL display element in a state where a transparent protective layer is laminated on both surfaces of a polarizer in which a dichroic dye is adsorbed and oriented on a polyvinyl alcohol (PVA) resin film, or in a state where an optical layer such as a retardation film or an optical compensation film having optical properties is bonded as necessary, to form an image display device.

In recent years, however, in image display devices for portable use such as mobile phones, the thickness of the entire module has been reduced in view of design and the like. Along with this, further thinning and weight reduction are also required for polarizing plates. For example, japanese patent application laid-open No. 2003-185842 (patent document 1) proposes: a polarizing plate having a protective layer formed on at least one side of a polarizer instead of a transparent protective film; japanese patent application laid-open No. 2010-9027 (patent document 2) proposes: a polarizing plate having a protective layer with improved durability in a high-temperature or high-humidity environment. In addition, japanese patent laid-open No. 2012 and 247574 (patent document 3) discloses that: a polarizing plate comprising a polarizer, a transparent protective layer provided only on one side of the polarizer, and a pressure-sensitive adhesive layer containing an alkali metal salt as an antistatic agent, without providing a transparent protective layer on the other side.

Documents of the prior art

Patent document

[ patent document 1] Japanese patent application laid-open No. 2003-185842

[ patent document 2] Japanese patent application laid-open No. 2010-9027

[ patent document 3] Japanese patent laid-open No. 2012 and 247574

Disclosure of the invention

Problems to be solved by the invention

However, when a conventional pressure-sensitive adhesive layer having antistatic properties is directly provided on a polarizing plate as described above, discoloration of a dichroic dye such as iodine that is adsorbed and oriented to a polyvinyl alcohol resin film constituting the polarizing plate (deterioration of the polarizing plate) may occur, and the method described in patent document 3 has room for improvement in optical durability.

The purpose of the present invention is to provide an adhesive-equipped polarizing plate that, even when an adhesive layer containing an antistatic agent is formed on at least one surface of the polarizing plate, is inhibited from being easily discolored or deteriorated when exposed to a high-temperature or high-humidity environment.

Another object of the present invention is to provide an adhesive-equipped polarizing plate in which a transparent protective layer is laminated on the adhesive-equipped polarizing plate, and an image display device in which the adhesive-equipped polarizing plate is applied to an image display element.

Means for solving the problems

The present invention has been made to solve the above problems. Specifically, the present invention has the following configurations.

[1] An adhesive-equipped polarizing plate, wherein an adhesive layer formed from an adhesive composition containing an antistatic agent is laminated on at least one side of the polarizing plate, the antistatic agent comprising: the resin composition comprises a salt of an anion having a fluoro group and a sulfonyl group, and at least 1 polyether selected from the group consisting of polyether esters, polyalkylene glycol monoalkyl ethers, and polyalkylene glycol dialkyl ethers.

[2] The adhesive-carrying polarizing plate according to [1], wherein,

the polyether is at least 1 selected from the group consisting of a compound represented by the following formula (I), a compound represented by the following formula (II), and a compound represented by the following formula (III),

(in the formula (I), m and n are each an integer, R¹And R²Represents an alkyl group. )

(in the formula (II), p is an integer, R³And R⁴Represents an alkyl group. )

R⁵(OCH₂CH₂)_nOR⁶ (III)

(in the formula (III), R⁵Represents an alkyl group having 1 to 12 carbon atoms, R⁶Represents a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, and n represents an integer of 3 to 6. )

[3] The adhesive-attached polarizing plate according to [2], wherein,

the polyether is at least 1 selected from the group consisting of a compound represented by the following formula (I) and a compound represented by the following formula (II),

(in the formula (II), p is an integer, R³And R⁴Represents an alkyl group. ).

[4] The adhesive-attached polarizing plate according to [2], wherein,

the polyether is a compound shown as the following formula (III),

R⁵(OCH₂CH₂)_nOR⁶ (III)

(in the formula, R⁵Represents an alkyl group having 1 to 12 carbon atoms, R⁶Represents a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, and n represents an integer of 3 to 6. ).

[5] The adhesive-attached polarizing plate according to any one of [1] to [4], wherein the adhesive composition comprises 100 parts by weight of an acrylic resin (A) which is a copolymer of a monomer mixture containing at least a (meth) acrylate monomer having an alkyl group with a carbon number of 1 to 18 and has a weight average molecular weight of 40 to 250 ten thousand and 0.001 to 10 parts by weight of a crosslinking agent (B).

[6] The adhesive-attached polarizing plate according to [5], wherein the acrylic resin (A) is a copolymer of a monomer mixture containing at least a carboxyl group-containing monomer in addition to a (meth) acrylate monomer having an alkyl group with 1 to 18 carbon atoms.

[7] The adhesive-attached polarizing plate according to [5], wherein the acrylic resin (A) is a copolymer of a monomer mixture containing a monomer having at least 1 olefinic double bond and at least 1 reactive functional group (excluding a carboxyl group) in a molecule in addition to a (meth) acrylate monomer having an alkyl group with 1 to 18 carbon atoms.

[8] The adhesive-carrying polarizing plate according to any one of [1] to [7], wherein the anion having a fluoro group and a sulfonyl group is at least 1 anion selected from a bis (fluoroalkylsulfonyl) imide ion, a tris (fluoroalkylsulfonyl) methide ion and a fluoroalkylsulfonic acid ion.

[9] The adhesive-carrying polarizing plate according to any one of [1] to [8], wherein the salt having an anion having a fluoro group and a sulfonyl group is a salt composed of an anion having a fluoro group and a sulfonyl group and any cation selected from an alkali metal ion, a group 2 element ion, a transition metal ion, and an amphoteric metal ion.

[10] The adhesive-carrying polarizing plate according to any one of [1] to [9], wherein the salt having an anion having a fluoro group and a sulfonyl group is at least 1 salt selected from an alkali metal salt of a bis (fluoroalkylsulfonyl) imide, an alkali metal salt of a tris (fluoroalkylsulfonyl) methide, and an alkali metal salt of a trifluoroalkylsulfonic acid.

[11] A polarizing plate with an adhesive, wherein a first transparent protective layer is laminated on one surface of the polarizer and the adhesive layer is laminated on the other surface of the polarizer in the polarizer with an adhesive according to any one of [1] to [10 ].

[12] The polarizing plate with an adhesive according to [11], wherein the first transparent protective layer is laminated on the polarizer with an adhesive layer interposed therebetween.

[13] The polarizing plate with an adhesive according to [11] or [12], wherein a second transparent protective layer is provided between the polarizer and the adhesive layer.

[14] The adhesive-attached polarizing plate according to any one of [11] to [13], wherein an optical layer is laminated on a surface of the first transparent protective layer on a side opposite to the polarizer.

[15] The pressure-sensitive adhesive-attached polarizing plate according to any one of [1] to [10] or the pressure-sensitive adhesive-attached polarizing plate according to any one of [11] to [14], wherein a release film is bonded to a surface of the pressure-sensitive adhesive layer.

[16] An image display device, wherein the polarizing plate with an adhesive according to any one of [1] to [10] or the polarizing plate with an adhesive according to any one of [11] to [14] is bonded to an image display element with an adhesive layer interposed therebetween.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, even when an adhesive layer containing an antistatic agent is directly formed on the surface of a polarizing plate, discoloration and deterioration of the polarizing plate can be suppressed when the polarizing plate is exposed to a high-temperature or high-humidity environment. Further, by laminating an adhesive layer on the polarizing plate, the polarizing plate and the image display device to which the adhesive layer is applied can be configured to be thinner and lighter. The polarizing plate with an adhesive of the present invention exhibits good durability even in a high-temperature, high-humidity and high-heat environment, and therefore an image display device in which the polarizing plate and an image display element are combined can be thinned and has excellent durability.

Drawings

Fig. 1 is a schematic cross-sectional view showing an example of a preferable layer structure of the polarizing plate with an adhesive of the present invention.

Fig. 2 is a schematic cross-sectional view showing another example of a preferable layer structure of the polarizing plate with an adhesive of the present invention.

Fig. 3 is a schematic cross-sectional view showing an example of a preferable layer structure of the image display device of the present invention.

Detailed Description

In the adhesive-attached polarizing plate of the present invention, an adhesive layer formed of an adhesive composition containing an antistatic agent is laminated on at least one surface of the polarizing plate, the antistatic agent containing: at least 1 polyether selected from polyether ester, polyalkylene glycol monoalkyl ether and polyalkylene glycol dialkyl ether, and a salt having an anion having a fluoro group and a sulfonyl group. The polarizing plate may be obtained by laminating a first transparent protective layer on one surface and an adhesive layer on the other surface. In addition, an adhesive-equipped polarizing plate having a second transparent protective layer between the polarizer and the adhesive layer of the adhesive-equipped polarizing plate may be manufactured. The polarizing plate with an adhesive is bonded to an image display element or the like including a liquid crystal cell to obtain an image display device. Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. The following description of the constituent elements is based on representative embodiments and specific examples, but the present invention is not limited to such embodiments.

[ adhesive composition (adhesive layer) ]

In the present invention, the adhesive layer is laminated on at least one surface of the polarizing plate. The adhesive layer is formed from an adhesive composition containing an antistatic agent. The antistatic agent contains a polyether and a salt having an anion having a fluoro group and a sulfonyl group.

(antistatic agent)

The antistatic agent in the present invention comprises a polyether and a salt having an anion having a fluoro group and a sulfonyl group, and is dispersed in a state where the salt having an anion having a fluoro group and a sulfonyl group is dissolved in the polyether, for example. In the present invention, the use of such an antistatic agent can prevent discoloration of the polarizing plate even when the adhesive composition is directly attached to the polarizing plate. In the present specification, "dispersion" means a state in which a salt having an anion having a fluoro group and a sulfonyl group is dispersed or dissolved in a polyether.

Examples of such antistatic agents include "Sankonol (registered trademark) AD 2326", "Sankonol (registered trademark) AD 2600", "Sankonol (registered trademark) TGR" (trade names given above) sold by the triplex chemical industry, ltd.

When a conventional adhesive composition containing an ionic compound is directly applied to a polarizing plate, the ionic compound has poor flowability and compatibility with an acrylic resin, and a cation bleeds out or blooms (blooms) and an iodide ion (I) of the polarizing plate³-、I^5-) Pseudo-bonding is formed, causing discoloration of the polarizing plate. On the other hand, the antistatic agent used in the present invention is preferably dispersed in a state dissolved in a polyether having a high affinity with an acrylic resin, because the generation of bleeding or blooming can be further suppressed. Further, the cation constituting the antistatic agent forms a lewis acid-base type complex ion with the polyether, and thus does not chemically bond with the iodide ion of the polarizing plate.

The content of the antistatic agent is preferably 0.01 to 30% by weight, more preferably 0.1 to 10% by weight, based on 100 parts by weight of the solid content of the binder composition. When the content of the antistatic agent is within the above range, sufficient antistatic performance can be exhibited, and problems such as precipitation of the antistatic agent in a low-temperature environment can be suppressed.

In the present invention, at least 1 compound selected from polyether esters, polyalkylene glycol monoalkyl ethers and polyalkylene glycol dialkyl ethers is used as the polyether. In the present invention, only polyether ester may be used, only polyalkylene glycol (di-or mono) -alkyl ether may be used, or 2 or more kinds may be used in combination. These polyethers function as plasticizers. In the present specification, the term "polyether" simply means the specific compound contained in the antistatic agent.

(polyether ester)

The polyether ester passes through the gaps between the resins that contain a polyether structure and an ester bond and become the main component of the adhesive composition, and thus prevents the resins from being regularly oriented. Further, the polyether ester preferably maintains an amorphous state even at a glass transition point or less. When polyether ester is used as the polyether contained in the antistatic agent, it is preferable that at least 1 kind of the compound represented by the following formula (I) or (II) is contained.

[ solution 1]

[ solution 2]

In the above formula (I), m and n are each an integer, R¹And R²Represents an alkyl group. m is preferably an integer of 1 to 40, and n is preferably an integer of 1 to 20. m and n are more preferably integers of 2 or more. In particular, m is preferably an integer of 2 or more. R¹And R²The alkyl group is preferably an alkyl group having 1 to 14 carbon atoms, and examples thereof include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, n-pentyl, n-nonyl, isononyl, n-decyl, and n-lauryl.

In the formula (II), p is an integer, and R is³And R⁴Represents an alkyl group. p is preferably an integer of 1 to 40, more preferably an integer of 2 or more. R³And R⁴The alkyl group is preferably an alkyl group having 1 to 14 carbon atoms, and examples thereof include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, n-pentyl, n-nonyl, isononyl, n-decyl, and n-lauryl.

As the polyether ester, a commercially available product can be used. Examples thereof include アデカサイザ (registered trademark) manufactured by ADEKA, HA-5 manufactured by Kao, D620 manufactured by J-PLUS, D623N and D643 manufactured by DIC, and モノサイザ -W-262 (registered trademark) manufactured by ポリサイザ (registered trademark) W-230-H, DIC manufactured by DIC.

(polyalkylene glycol (di-or mono) alkyl ether)

The polyalkylene glycol (di-or mono) -alkyl ether has a property of being easily dissolved in a resin which becomes a main component of the adhesive composition. As the polyalkylene glycol (di-or mono) -alkyl ether contained in the antistatic agent, a compound represented by the following formula (III) is preferably used.

R⁵(OCH₂CH₂)_nOR⁶ (III)

In the formula (III), R⁵Represents an alkyl group having 1 to 12 carbon atoms, R⁶Represents a hydrogen atom or an alkyl group having 1 to 12 carbon atoms. n represents an integer of 3 to 6.

Examples of the polyalkylene glycol (di-or mono) -alkyl ether include triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, heptaethylene glycol dimethyl ether, hexaethylene glycol dimethyl ether, triethylene glycol monomethyl ether, tetraethylene glycol monomethyl ether, (dodecyloxy) triethylene glycol monomethyl ether, and (dodecyloxy) tetraethylene glycol monomethyl ether.

The molecular weight of the polyether is preferably 250 to 2000, more preferably 500 to 1500. The viscosity (25 ℃) is preferably 30 to 600 mPas.

The polyether described above has low viscosity, good workability, flexibility at low temperature, and a balance between flexibility and durability, and is excellent in heat aging resistance, nonvolatility, non-migration property, oil resistance, and safety (PL suitability).

(other plasticizers)

The antistatic agent may further contain a plasticizer in addition to the above polyether. Examples of such a plasticizer include a plasticizer containing an ester of a mono-or dicarboxylic acid having a saturated or unsaturated chain hydrocarbon group and an alcohol having a chain hydrocarbon group having 1 to 20 carbon atoms, or an ester in which an unsaturated group in an unsaturated chain hydrocarbon group is epoxidized. By using such an ester, the wettability of the pressure-sensitive adhesive layer to the adherend can be improved, inclusion of air bubbles during bonding can be made less likely, bleeding of the plasticizer from the pressure-sensitive adhesive layer is made less likely to occur, and contamination of the adherend can be reduced suitably.

As the saturated or unsaturated chain hydrocarbon group in the mono-or dicarboxylic acid component constituting the ester, an alkyl group or an alkylene group can be used, and among them, an alkyl group or an alkylene group having 1 to 20 carbon atoms is preferable, an alkyl group having 4 to 18 carbon atoms is more preferable, and an alkyl group having 4 to 14 carbon atoms is particularly preferable. When the number of carbon atoms of the chain hydrocarbon group is 3 or more, the chain hydrocarbon group may be branched or straight. The mono-or dicarboxylic acid having such a saturated or unsaturated chain hydrocarbon group has a carbon number close to the carbon number of the acrylic monomer constituting the acrylic resin used in the adhesive composition, and thus has good compatibility with the adhesive composition, can be suitably held in the adhesive composition, and can suppress bleeding.

Examples of the dicarboxylic acid having a saturated or unsaturated chain hydrocarbon group include mono-and polyesters of linear aliphatic dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, fumaric acid, maleic acid, itaconic acid, and dodecanedioic acid. Examples of the monocarboxylic acid having a saturated chain hydrocarbon group include acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, isovaleric acid, caproic acid, isocaproic acid, heptanoic acid, caprylic acid, 2-ethylhexanoic acid, pelargonic acid, capric acid, undecanoic acid, lauric acid, tridecanoic acid, myristic acid, pentadecanoic acid, palmitic acid, heptadecanoic acid, stearic acid, isostearic acid, nonadecanoic acid, and arachidic acid. Examples of the monocarboxylic acid having an unsaturated chain hydrocarbon group include unsaturated fatty acids such as crotonic acid, angelic acid, linderac acid, myristoleic acid, palmitoleic acid, oleic acid, octadecenoic acid, gadoleic acid, eicosenoic acid, erucic acid, nervonic acid, linoleic acid, eicosadienoic acid, docosadienoic acid, linolenic acid, pinolenic acid, eleostearic acid, eicosatrienoic acid, linoleic acid, arachidonic acid, eicosatetraenoic acid, adrenic acid, elaidic acid, and docosahexaenoic acid.

As the chain hydrocarbon group having 1 to 20 carbon atoms in the alcohol constituting the ester, an alkyl group or an alkylene group having 1 to 20 carbon atoms, particularly an alkyl group, is suitably used, and among them, an alkyl group having 4 to 18 carbon atoms is preferable, and an alkyl group having 4 to 14 carbon atoms is particularly preferable. The alcohol having such a saturated or unsaturated chain hydrocarbon group has a carbon number close to the carbon number of the acrylic monomer constituting the acrylic resin contained in the adhesive composition, and thus has good compatibility with the adhesive composition, can be suitably held in the adhesive composition, and can suppress bleeding. By making the carbon number of the hydrocarbon group of the alcohol component closer to the carbon number of the acrylic monomer constituting the acrylic resin used in the pressure-sensitive adhesive composition than the carboxylic acid component constituting the ester, the adherend contamination can be easily suppressed particularly.

Examples of the alcohol having such a chain hydrocarbon group include straight-chain and branched-chain alcohols such as methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutanol, 1-pentanol, 2-pentanol, 3-pentanol, isopentanol, 1-hexanol, 2-hexanol, 3-hexanol, octanol, 2-ethyl-1-hexanol, nonanol, 3, 5-trimethyl-1-hexanol, decanol, undecanol, lauryl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol, isostearyl alcohol, oleyl alcohol, and eicosanol. Among them, 1-butanol, 2-butanol, isobutanol, 1-pentanol, 2-pentanol, 3-pentanol, isopentanol, 1-hexanol, 2-hexanol, 3-hexanol, octanol, 2-ethyl-1-hexanol, nonanol, 3, 5-trimethyl-1-hexanol, and decanol, which are alcohols having 4 to 10 carbon atoms, can be particularly preferably used.

Further, it is preferable to use an ester of the above-mentioned mono-or dicarboxylic acid with an alcohol as a plasticizer. The ester may have a skeleton containing a saturated or unsaturated hydrocarbon group, but is preferably an ester having no skeleton containing an unsaturated hydrocarbon group. In addition, an epoxidized ester in which an unsaturated bond of an ester having a skeleton containing an unsaturated hydrocarbon group is epoxidized may be preferably used. Among them, adipic acid monoester, sebacic acid monoester, and epoxidized fatty acid monoester can be particularly preferably used.

The ester used as the plasticizer may be selected from monoesters and polyesters, but is preferably an ester having a weight average molecular weight of 1000 or less in terms of PS, and particularly preferably 300 to 800, because it is easy to control the solubility parameter (SP value) in an appropriate range and improve the compatibility with the adhesive composition.

As the plasticizer, a plasticizer having a solubility parameter (SP value) of 8.5 or less is preferably used. Among them, it is preferably 7.0 to 8.4. When the SP value of the plasticizer is 8.5 or less, the plasticizer is excellent in compatibility with the acrylic resin, and therefore, even when the pressure-sensitive adhesive composition is left in a state of being attached to a polarizing plate for a long time in a high-humidity and hot environment, fogging is less likely to occur on the surface of the polarizing plate when the pressure-sensitive adhesive composition is peeled from the surface of the polarizing plate. As the SP value of the plasticizer, plasticizers larger than 7 can be generally used. Further, the above SP value is based on the Small formula proposed by j.small [ p.a.j.small: calculated values of j.appl.chem., 3, 71(1953) ].

The plasticizer is preferably added in an amount of 0.5 to 30 parts by weight, more preferably 1 to 20 parts by weight, and particularly preferably 1 to 10 parts by weight, based on 100 parts by weight of the solid content of the (meth) acrylic copolymer constituting the acrylic resin. If the amount of the plasticizer added is more than 0.5 part by weight, bubbles are liable to escape during attachment. When the amount is less than 30 parts by weight, fogging is less likely to occur on the display surface even in a high-humidity environment.

(salt having an anion having a fluoro group and a sulfonyl group)

The salt having an anion having a fluoro group and a sulfonyl group is easily dissolved in the polyether, and the salt concentration in the plasticizer can be increased. By dispersing the solution in the adhesive composition, the salt having the anion having the fluoro group and the sulfonyl group can be incorporated into the adhesive composition in a large amount and uniformly.

The solution containing the salt having an anion having a fluoro group and a sulfonyl group and the polyether exhibits antistatic properties and imparts plasticization together with plasticization of the polyether in the adhesive composition. Further, since the polyether can be close to the solubility parameter (SP value) of the adhesive composition, the polyether has excellent affinity and does not bleed out. Further, a pressure-sensitive adhesive composition which is free from transfer contamination, independent of humidity, excellent in quick-acting properties, and capable of sustaining excellent antistatic properties can be obtained.

The salt having an anion having a fluoro group and a sulfonyl group exhibits antistatic properties while maintaining adhesive properties in the adhesive composition. Further, since the salt having an anion having a fluoro group and a sulfonyl group is excellent in compatibility with the constituent components of the pressure-sensitive adhesive composition, the pressure-sensitive adhesive composition can be obtained which is free from bleeding, blooming, and transfer contamination, is independent of humidity, is excellent in immediate effect, and has excellent antistatic properties.

The anion having a fluoro group and a sulfonyl group is preferably an anion selected from the group consisting of a bis (fluoroalkylsulfonyl) imide ion, a tris (fluoroalkylsulfonyl) methide ion and a fluoroalkylsulfonic acid ion.

The salt having an anion having a fluoro group and a sulfonyl group is preferably a salt containing any cation of an alkali metal, a group 2 element, a transition metal, or an amphoteric metal, and the anion having a fluoro group and a sulfonyl group. The salt having an anion having a fluoro group and a sulfonyl group is particularly preferably an alkali metal salt of a bis (fluoroalkylsulfonyl) imide ion, an alkali metal salt of a tris (fluoroalkylsulfonyl) methide ion, and an alkali metal salt of a fluoroalkylsulfonic acid ion. Lithium salts are particularly preferred.

Among the salts composed of the above anions and cations, a salt containing a bis (fluoroalkylsulfonyl) imide ion, a tris (fluoroalkylsulfonyl) methide ion, and a fluoroalkylsulfonic acid ion is preferable. Specifically, lithium bis (trifluoromethanesulfonyl) imide [ LiN (SO)₂CF₃)₂Potassium bis (trifluoromethanesulfonyl) imide [ KN (SO)₂CF₃)₂Sodium bis (trifluoromethanesulfonyl) imide [ NaN (SO)₂CF₃)₂Lithium tris (trifluoromethanesulfonyl) methide [ LiC (SO)₂CF₃)₃Potassium tris (trifluoromethanesulfonyl) methide [ KC (SO)₂CF₃)₃Sodium tris (trifluoromethanesulfonyl) methide [ NaC (SO)₂CF₃)₃Lithium trifluoromethanesulfonate [ LiSO ]₃CF₃Potassium triflate [ KSO ]₃CF₃Sodium trifluoromethanesulfonate [ NaSO ]₃CF₃And (c) a temperature sensor. Among them, lithium bis (trifluoromethanesulfonyl) imide, lithium tris (trifluoromethanesulfonyl) methide, and lithium trifluoromethanesulfonate are more preferable. In particular, lithium bis (trifluoromethanesulfonyl) imide, and lithium trifluoromethanesulfonate are preferred.

For example, lithium bis (trifluoromethanesulfonyl) imide [ LiN (SO)₂CF₃)₂As a salt, and dissolved in a polyether containing diethylene glycol and adipic acid, lithium ions are coordinated to the ether oxygen atom in polyethylene glycol. When the binder composition is used to form the binder layer, lithium ions are coordinated to ether oxygen atoms to form the binder layer in which the lithium ions are uniformly dispersed, and when an electric field is applied from the outside, lithium is present in the binder layerThe ions move (ion transport) to the corresponding poles to exhibit ion conductivity.

Lithium bis (trifluoromethanesulfonyl) imide [ LiN (SO)₂CF₃)₂Dissolved in tetraethylene glycol dimethyl ether, the ether group as a polar group is coordinated to Li⁺The state of the ion, dispersed in the composition in this state. Li⁺Ions surrounded by ether oxygen, from N (SO)₂CF₃)₂ ^-Ions are dissociated, and thus contribute greatly to antistatic properties. In particular, the mixture of lithium salt and polyether forms complex ions of the lewis acid-base type, and thus contributes particularly greatly to antistatic property. In addition, the lithium salt forms a lewis acid-base type complex ion with the polyether, and thus cannot form a chemical bond with an iodide ion of the polarizing plate. Therefore, discoloration of the polarizing plate is not caused.

The salt having an anion having a fluoro group and a sulfonyl group is contained in an amount of preferably 0.1 to 200 parts by weight, more preferably 1 to 180 parts by weight, and still more preferably 5 to 150 parts by weight, based on 100 parts by weight of the polyether.

The salt having an anion having a fluoro group and a sulfonyl group is preferably contained in an amount of 0.01 to 30 parts by weight based on 100 parts by weight of the adhesive composition. By setting the content of the salt having an anion having a fluoro group and a sulfonyl group within the above range, sufficient antistatic performance can be exhibited.

(Polymer type antistatic agent)

The antistatic agent may further contain a polymer type antistatic agent. The polymeric antistatic agent can stabilize salts having anions. Further, it is considered that since the salt having an anion is dispersed in a state of being dissolved in the polyether, the salt is accumulated in a place where the polymer type antistatic agent having an affinity with the polyether exists, and stabilization is achieved by the affinity of both. Examples of such a polymeric antistatic agent include a polyether block polyolefin copolymer, a polyoxyalkylene copolymer, and an ethylene oxide-propylene oxide-allyl glycidyl copolymer.

The polymeric antistatic agent is preferably contained in an amount of 0.1 to 65 parts by weight based on 100 parts by weight of the adhesive composition.

(acrylic resin)

The main component of the pressure-sensitive adhesive composition of the present invention is preferably a product obtained by crosslinking an acrylic resin with a crosslinking agent. The "main component" means that the binder is contained in an amount of 50% by weight or more based on the whole binder.

In the present invention, the acrylic resin (a) contained in the adhesive composition is a copolymer of a monomer mixture containing at least a (meth) acrylate monomer having an alkyl group with 1 to 18 carbon atoms, and the weight average molecular weight thereof is preferably 40 to 250 ten thousand. Further, "(meth) acrylic" means acrylic or methacrylic. The same applies to other "(methyl)" s.

Examples of the (meth) acrylate monomer having an alkyl group having 1 to 18 carbon atoms (hereinafter referred to as a non-crosslinkable acrylic monomer) include (meth) acrylates in which a hydrogen atom of a carboxyl group of (meth) acrylic acid is substituted with a hydrocarbon group. The number of carbon atoms in the hydrocarbon group is preferably 1 to 18, more preferably 1 to 8. In addition, the hydrocarbon group may have a substituent. The substituent may not contain a crosslinkable group, and examples thereof include alkoxy groups such as methoxy group and ethoxy group. Specific examples of such (meth) acrylic esters include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, n-pentyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, n-nonyl (meth) acrylate, isononyl (meth) acrylate, n-decyl (meth) acrylate, isodecyl (meth) acrylate, n-undecyl (meth) acrylate, n-dodecyl (meth) acrylate, stearate, methoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate, cyclohexyl (meth) acrylate, and the like, Benzyl (meth) acrylate. These may be used alone in 1 kind, or may be used in combination of 2 or more kinds. Among these, n-butyl acrylate, 2-ethylhexyl acrylate and methyl acrylate are preferable from the viewpoint of adhesiveness.

The content of the structural unit derived from the non-crosslinkable acrylic monomer in the acrylic resin (A) is preferably 60 to 99.99% by weight, more preferably 65 to 99.9% by weight. When the content is not less than the lower limit, sufficient adhesive force can be exhibited, and when the content is not more than the upper limit, crosslinking can be sufficiently performed by the crosslinking agent.

The acrylic resin (a) is preferably a copolymer of a monomer mixture containing at least a monomer having 1 olefinic double bond and at least 1 reactive functional group in the molecule in addition to the non-crosslinkable acrylic monomer. The monomer having 1 olefinic double bond and at least 1 reactive functional group in the molecule (hereinafter referred to as a crosslinkable monomer) may be an acrylic monomer or a non-acrylic monomer if it is a monomer polymerizable with a non-crosslinkable acrylic monomer, but is preferably an acrylic monomer. Examples of the reactive functional group include a carboxyl group, a hydroxyl group, an amino group, an epoxy group, and a glycidyl group.

Examples of the carboxyl group-containing monomer include α, β -unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, and glutaconic acid, and anhydrides thereof.

Examples of the hydroxyl group-containing monomer include hydroxyalkyl (meth) acrylates such as 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and 2-hydroxypropyl (meth) acrylate, [ (mono-, di-, or poly-) alkylene glycol ] esters of (meth) acrylic acid such as mono (diethylene glycol) ester of (meth) acrylic acid, and (meth) acrylic acid lactones such as monocaprolactone (meth) acrylate.

Examples of the amino group-containing monomer include (meth) acrylamide, N-dimethyl (meth) acrylamide, N-butyl (meth) acrylamide, and allylamide.

Examples of the glycidyl group-containing monomer include glycidyl (meth) acrylate and the like.

These crosslinking monomers may be used alone in 1 kind, or may be used in combination in 2 or more kinds.

The content of the structural unit derived from the crosslinkable monomer in the acrylic resin (a) is preferably 0.01 to 40% by weight, more preferably 0.5 to 35% by weight. When the content is not less than the lower limit, sufficient crosslinking can be achieved, and when the content is not more than the upper limit, the adhesive strength tends to be easily controlled, and the reworkability of the resulting adhesive tends to be good.

When a carboxyl group-containing monomer as a crosslinkable monomer is copolymerized, heat resistance tends to be improved. When the carboxyl group-containing monomer is copolymerized, the content of the structural unit derived from the carboxyl group-containing monomer in the acrylic resin (a) is preferably 0.01 to 20% by weight, more preferably 0.05 to 10% by weight. When the content of the carboxyl group-containing monomer is 0.05% by weight or more, the heat resistance is improved in a high-temperature or high-humidity environment or an environment in which heating and cooling are repeated. When the content of the carboxyl group-containing monomer is not more than the upper limit, the adhesive strength can be easily controlled, and the reworkability of the glass which is peeled off and reused is also good. As the carboxyl group-containing monomer, (meth) acrylic acid is preferable.

On the other hand, when a carboxyl group-containing monomer is not used as a crosslinkable monomer, the obtained pressure-sensitive adhesive layer can be a layer substantially free of an acid component. Thus, for example, even if the adhesive composition or the adhesive layer is brought into contact with a film having corrosiveness such as a tin-doped indium oxide film, a metal film or the like, the film is not corroded. Therefore, when the pressure-sensitive adhesive composition or the pressure-sensitive adhesive layer is disposed in direct contact with a transparent conductive film such as a capacitive touch panel using such a corrosive film, the transparent conductive film is not corroded, and an increase in the electrical resistance value of the conductive film can be suppressed. From the viewpoint of such corrosion resistance, the amount of the carboxyl group-containing monomer used in the polymerization of the (meth) acrylic copolymer (a) is preferably less than 0.5% by weight, and more preferably less than 0.05% by weight.

In order to form such an adhesive layer, a hydroxyl group-containing monomer or an amino group-containing monomer is preferable as the crosslinkable monomer, and these monomers can be used in combination, from the viewpoint of good adhesiveness, crosslinkability, polymerizability, and durability, and further removability and good reworkability of recycled glass. As the hydroxyl group-containing monomer, hydroxyalkyl (meth) acrylates are preferred, and 2-hydroxyethyl (meth) acrylate and 4-hydroxybutyl (meth) acrylate are particularly preferred. As the amino group-containing monomer, (meth) acrylamide, N-dimethyl (meth) acrylamide, N-butyl (meth) acrylamide are preferable.

The acrylic resin (a) may have a structural unit derived from a monomer other than the non-crosslinkable acrylic monomer and the crosslinkable monomer. Examples of such monomers include (meth) acrylonitrile, vinyl acetate, styrene, vinyl chloride, vinyl pyrrolidone, and vinyl pyridine.

The content of the structural unit derived from another monomer in the acrylic resin (A) is preferably 0 to 20% by weight, more preferably 0.5 to 10% by weight. If the content is not less than the lower limit, the physical properties can be easily adjusted, and if the content is not more than the upper limit, yellowing and the like due to aging deterioration can be prevented.

The weight average molecular weight Mw of the acrylic resin (a) which is a copolymer of the above-described monomers is preferably 40 to 250 ten thousand, more preferably 50 to 200 ten thousand, still more preferably 100 to 200 ten thousand, and particularly preferably 150 to 200 ten thousand. When the weight average molecular weight is within the above range, a sufficient cohesive force can be exerted, and durability can be improved. In addition, an increase in viscosity of the coating liquid containing the pressure-sensitive adhesive composition can be suppressed, and the pressure-sensitive adhesive layer can be easily formed by coating. The weight average molecular weight can be measured by Gel Permeation Chromatography (GPC) and is a weight average molecular weight in terms of standard Polystyrene (PS).

(crosslinking agent)

As the crosslinking agent, a crosslinking agent capable of reacting with a monomer having a reactive functional group is preferably used. Examples thereof include isocyanate compounds, epoxy compounds, oxazoline compounds, aziridine compounds, metal chelate compounds, and butylated melamine compounds. Among these crosslinking agents, isocyanate compounds, epoxy compounds and metal chelate compounds are preferable because they can easily crosslink the acrylic resin. In particular, when only a hydroxyl group-containing monomer is used as the crosslinkable monomer, an isocyanate compound is preferably used from the viewpoint of reactivity of the hydroxyl group.

Examples of the isocyanate compound include toluene diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, and isophorone diisocyanate. Examples of the epoxy compound include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, glycerol diglycidyl ether, neopentyl glycol diglycidyl ether, 1, 6-hexanediol diglycidyl ether, tetraglycidyl xylylenediamine, 1, 3-bis (N, N-diglycidylaminomethyl) cyclohexanone, trimethylolpropane polyglycidyl ether, diglycerol polyglycidyl ether, polyglycerol polyglycidyl ether, sorbitol polyglycidyl ether, and the like. The content of the crosslinking agent is preferably selected as appropriate in accordance with the desired adhesive properties. These crosslinking agents may be used alone or in combination of 2 or more.

The content of the crosslinking agent is preferably 0.001 to 10 parts by weight, more preferably 0.01 to 5 parts by weight, based on 100 parts by weight of the solid content of the acrylic resin (A). If the value is not less than the lower limit, foaming can be suppressed, and if the value is not more than the upper limit, sufficient stress relaxation performance can be obtained.

(additives)

The pressure-sensitive adhesive composition of the present invention may contain components other than the acrylic resin (a), the crosslinking agent, and the antistatic agent. For example, in addition to the acrylic resin (a), a polyester resin, an amino resin, an epoxy resin, or a urethane resin may be used in combination.

The pressure-sensitive adhesive composition of the present invention may contain additives such as antioxidants, metal corrosion inhibitors, tackifiers, silane coupling agents, ultraviolet absorbers, light stabilizers such as hindered amine compounds, and fillers, as necessary. Examples of the antioxidant include a phenol-based antioxidant, an amine-based antioxidant, a lactone-based antioxidant, a phosphorus-based antioxidant, and a sulfur-based antioxidant. These antioxidants may be used alone in 1 kind, or may be used in combination in 2 or more kinds. As the metal corrosion inhibitor, a benzotriazole-based resin is preferable from the viewpoint of high compatibility with the binder and high effect. Examples of the tackifier include rosin-based resins, terpene-phenol-based resins, coumarone-indene-based resins, styrene-based resins, xylene-based resins, phenol-based resins, petroleum resins, and the like. Examples of the silane coupling agent include mercaptoalkoxysilane compounds (e.g., mercapto-substituted alkoxy oligomers), and the like. Examples of the ultraviolet absorber include benzotriazole compounds, benzophenone compounds, and triazine compounds.

The content of these additives is usually preferably 0.01 to 10 parts by weight, more preferably 0.05 to 5 parts by weight, and particularly preferably 0.1 to 3 parts by weight, based on 100 parts by weight of the solid content of the adhesive composition.

(method for producing adhesive composition)

The pressure-sensitive adhesive composition can be produced by dispersing a salt having an anion having a fluoro group and a sulfonyl group in a composition containing a pressure-sensitive adhesive resin such as an acrylic resin (a). The manufacturing method comprises: preparing a salt solution containing a polyether and a salt having an anion having a fluoro group and a sulfonyl group; a step of kneading a salt solution (component 1) and an adhesive resin (component 2) to form a composition; and a step of further kneading or blending the composition with an adhesive resin (component 2). By kneading the components 1 and 2, the salt solution is dispersed or dissolved in the composition in the form of fine droplets. Then, the adhesive resin (component 2) is further kneaded or blended in a state where the salt is dissolved in the composition, and thus the salt is further dispersed in the adhesive resin (component 2) in a uniformly compatible state.

(adhesive layer)

The thickness of the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition may be 100 μm or less, and preferably about 5 to 50 μm. When the pressure-sensitive adhesive layer is applied to a polarizing plate, or the like, it is desirable that the pressure-sensitive adhesive layer be formed to be thin within a range that does not impair the properties such as processability and durability, and for example, a thickness of 3 to 25 μm is suitable for obtaining good durability while maintaining good processability.

The adhesive composition may be formed into a sheet to obtain an adhesive sheet. The adhesive sheet can be produced by, for example, dissolving an adhesive in a solvent, applying the solution, and then removing the solvent. As the coating method, a blade coating method, a micro-bar coating method, an air knife coating method, a reverse roll coating method, a reverse gravure coating method, a variable gravure coating method, a die coating method, a curtain coating method, or the like can be suitably selected. When the pressure-sensitive adhesive sheet is used, the application and drying steps of the pressure-sensitive adhesive in the bonding step are not required, and the pressure-sensitive adhesive sheet can be laminated between the objects to be bonded and then pressed to bond the objects to be bonded, which is simple.

The adhesive sheet is preferably a sheet having a structure in which a release film (also referred to as a spacer) having a release agent provided on a base material is provided on one surface or both surfaces of the adhesive sheet. For example, a double-sided adhesive sheet with a release sheet in which release films are provided on both sides of an adhesive layer can be obtained by: after a release layer surface of a1 st release film provided with a release agent layer on a polymer film is coated with an adhesive coating liquid and dried, a release layer surface of a 2 nd release film including a release agent layer having a release force different from that of the 1 st release film is bonded and pressure bonded to the adhesive layer. When the peeling forces of the 1 st and 2 nd release films are close to each other, a stringiness separation (corresponding to れ) phenomenon in which the adhesive floats from the release film on the heavy peeling force side occurs when the release film on the light peeling force side is peeled. Therefore, the peeling force of the peeling film on the heavy peeling force side is preferably 0.05 to 0.15N, and the peeling force of the peeling film on the light peeling force side is preferably 0.01 to 0.04N.

In this case, when the difference in the peeling force between the two release films is maintained, the adhesive coating liquid may be applied to the 2 nd release film, and then the 1 st release film may be bonded and pressure-bonded. The adhesive sheet may be in the form of a sheet or may be wound into a roll.

[ polarizing plate ]

The polarizing plate is a film having a function of extracting linearly polarized light from incident natural light, and a film in which a dichroic dye is adsorbed and aligned on a polyvinyl alcohol resin film can be used. Examples of the raw material for producing the polarizing plate include a polyvinyl alcohol resin film and a film in which a dichroic dye is adsorbed and oriented on a polyvinyl alcohol resin described in jp 2012-159778 a. The polyvinyl alcohol resin constituting the polarizing plate can be obtained by saponifying a polyvinyl acetate resin. Examples of the polyvinyl acetate resin include polyvinyl acetate which is a homopolymer of vinyl acetate, and a copolymer of vinyl acetate and another monomer copolymerizable therewith. Examples of the other monomer copolymerizable with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and acrylamides having an ammonium group. The saponification degree of the polyvinyl alcohol resin is usually 85 mol% or more, preferably 98 mol% or more. The polyvinyl alcohol resin may be further modified, and for example, polyvinyl formal, polyvinyl acetal, or the like modified with aldehydes may be used. The polymerization degree of the polyvinyl alcohol resin is usually about 1,000 to 10,000, preferably about 1,500 to 5,000.

In the present invention, as the polyvinyl alcohol resin, a suitable commercially available product can be used. Examples of suitable commercial products are: "PVA 124", "PVA 117", "PVA 624" and "PVA 617" available from Coli, and "N-300" and "NH-18", "AH-22" and "AH-26" available from synthetic chemical industry, and "JC-33", "JF-17L", "JF-20", "JM-26", "JM-33" and "JP-45" available from VAM & POVAL, respectively.

A film formed from such a polyvinyl alcohol resin can be used as a raw material film for a polarizing plate. The polyvinyl alcohol resin can be formed into a film by a known method. The thickness of the raw material film containing the polyvinyl alcohol resin is, for example, about 1 to 150 μm. Also considering the elongation, the film thickness is preferably 3 μm or more.

The polarizing plate was finally dried by the following steps: a step of uniaxially stretching the polyvinyl alcohol resin film and the polyvinyl alcohol resin described in Japanese unexamined patent application publication No. 2012-159778; a step of dyeing a polyvinyl alcohol resin or film with a dichroic dye to allow the dichroic dye to adsorb; treating the polyvinyl alcohol resin or film having the dichroic dye adsorbed thereon with an aqueous boric acid solution; and a step of washing with water after the treatment with the aqueous boric acid solution.

In addition, the polarizing plate can be manufactured by the following method: a method in which a solution of a polyvinyl alcohol resin is applied to a substrate or the like and dried, and then the substrate is stretched together with the substrate to remove the substrate. Examples of the substrate include a polyethylene terephthalate film, a polycarbonate film, a triacetyl cellulose film, a norbornene film, a polyester film, and a polystyrene film. The method can easily produce a polarizer layer with a thickness of 7 μm or less.

The transmittance Ty of the polarizer or polarizing plate is preferably 40% to 44%, more preferably 42% to 44%, and still more preferably 42.5% to 44%.

The polarization degree Py of the polarizer or polarizing plate is 99% or more, preferably 99.9% or more.

In the present invention, the thickness of the polarizer layer is preferably 1 to 50 μm, and more preferably 2 to 30 μm, from the viewpoint of thinning.

In the present invention, a pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition is laminated on at least one surface of a polarizing plate comprising the polyvinyl alcohol resin described above. By using such an adhesive composition, in the present invention, the polarizing plate and the adhesive layer are flexibly adhered to each other, and discoloration and deterioration of the polarizing plate can be suppressed under a high-temperature, high-humidity environment.

The formation of the adhesive layer on the polarizing plate can be performed, for example, by the following method: a method of applying an adhesive composition to a polarizing plate and drying the same, and a method of producing the above-mentioned double-sided adhesive sheet with a release sheet, and peeling off a release film on one side and bonding the same to a polarizing plate with an exposed adhesive layer interposed therebetween. In the pressure-sensitive adhesive layer, a release film is preferably laminated on the surface opposite to the polarizing film.

[ polarizing plate with adhesive ]

The adhesive-equipped polarizer of the present invention can be obtained by laminating the adhesive layer on one surface of the polarizer and laminating the first transparent protective layer on the other surface.

(transparent protective layer)

The first transparent protective layer laminated on one surface of the polarizing plate may be formed of a suitable transparent resin film or a cured product of an active energy ray-curable resin composition. As the transparent resin film, a film formed of a resin excellent in transparency, uniformity of optical characteristics, mechanical strength, thermal stability, and the like is preferably used. Examples thereof include cellulose resin films such as triacetyl cellulose and diacetyl cellulose; polyester resin films such as polyethylene terephthalate, polyethylene isophthalate, and polybutylene terephthalate; acrylic resin films such as polymethyl (meth) acrylate and polyethyl (meth) acrylate; polycarbonate resin films, polyether sulfone resin films, polysulfone resin films, polyimide resin films, polyolefin resin films, and cyclic olefin resin films containing cyclic olefins such as norbornene as monomers. Among them, cellulose-based resin films, acrylic resin films, and cycloolefin-based resin films are preferable.

When a cellulose-based resin film is used as the transparent protective layer, a cellulose acetate-based resin in which at least a part of cellulose is esterified with acetic acid is suitable. For example, triacetyl cellulose, diacetyl cellulose, cellulose acetate propionate and the like can be given. Suitable commercially available products can be used for the cellulose acetate resin film. For example, "FujiTAC (registered trademark) TD 80", "FujiTAC (registered trademark) TD80 UF", and "FujiTAC (registered trademark) TD80 UZ" sold by FujiTAC (registered trademark) strain, and "KC 8UX 2M" and "KC 8 UY" sold by konica minolta optical strain, and the like (both trade names) are suitable.

The acrylic resin film is a film formed of an acrylic resin obtained by mixing and melt-kneading a methacrylic resin and additives and the like added as needed. The methacrylic resin is a polymer mainly composed of methacrylic acid ester. The methacrylic resin may be a homopolymer of 1 kind of methacrylic acid ester, or a copolymer of methacrylic acid ester with other methacrylic acid ester, acrylic acid ester, or the like. Examples of the methacrylic acid ester include alkyl methacrylates such as methyl methacrylate, ethyl methacrylate and butyl methacrylate, and the number of carbon atoms in the alkyl group is usually about 1 to 4. The acrylic ester copolymerizable with the methacrylic acid ester is preferably an alkyl acrylate, and examples thereof include methyl acrylate, ethyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate, and the carbon number of the alkyl group is usually about 1 to 8. In addition, the copolymer may contain an aromatic vinyl compound such as styrene having at least 1 polymerizable carbon-carbon double bond in the molecule, a vinyl cyanide compound such as acrylonitrile, and the like.

The acrylic resin may have a ring structure in the main chain of the polymer because the durability of the film can be improved. The ring structure is preferably a heterocyclic structure such as a cyclic acid anhydride structure, a cyclic imide structure, or a lactone ring structure. Specifically, a cyclic acid anhydride structure such as a glutaric anhydride structure and a succinic anhydride structure, a cyclic imide structure such as a glutarimide structure and a succinimide structure, and a lactone ring structure such as butyrolactone and valerolactone may be mentioned.

The acrylic resin film preferably contains acrylic rubber particles from the viewpoint of impact resistance and film formability of the film. The amount of the acrylic rubber particles that the acrylic resin may contain is preferably 5% by weight or more, and more preferably 10% by weight or more, relative to 100% by weight of the acrylic resin. Although the upper limit of the amount of the acrylic rubber particles is not critical, if the amount of the acrylic rubber particles is too large, the surface hardness of the film is lowered, and when the film is subjected to surface treatment, the solvent resistance to the organic solvent in the surface treatment agent is lowered. Therefore, the amount of the acrylic rubber particles that the acrylic resin may contain is preferably 80 wt% or less, and more preferably 60 wt% or less.

The cycloolefin resin is, for example, a thermoplastic resin having monomer units of a cycloolefin typified by norbornene, tetracyclodecene (also called dimethanonaphthalene) or a derivative thereof, and may be a hydrogenated product of a ring-opened polymer of the cycloolefin or a ring-opened copolymer using 2 or more kinds of the cycloolefins, or an addition polymer of a cycloolefin and an aromatic compound having a chain olefin or a vinyl group. In addition, a polar group may be introduced.

Examples of commercially available cycloolefin resins include ARTON (registered trademark) sold by JSR (strain), ZEONEX (registered trademark) and ZEONOR (registered trademark) sold by nippon (strain), produced by TOPAS ADVANCED POLYMERS GmbH of germany, "TOPAS (registered trademark)" sold by polyplatices (strain) in japan, and Apelle (registered trademark) sold by mitsui chemical corporation (all trade names).

When a film is obtained by forming such a cycloolefin resin into a film, a known film forming method such as a solvent casting method or a melt extrusion method is suitably used for film formation. A cycloolefin resin film formed into a film and a cycloolefin resin film further stretched to impart a retardation are also commercially available. For example, there are "ARTON membrane" sold by JSR (strain) (the "ARTON" is a registered trademark of the company), a "ZEONOR membrane" (a registered trademark) sold by nippon (strain), an "Escena" (a registered trademark) and "SCA 40" (both trade names) sold by ponding chemical industry (strain), and the like, which can be suitably used.

The transparent resin film can be laminated on the polarizing plate by using a suitable adhesive or bonding agent. Examples of the adhesive include an active energy ray-curable adhesive and an aqueous adhesive. The active energy ray-curable adhesive may be an adhesive whose curing component is cationically polymerizable, an adhesive whose curing component is radically polymerizable, or both. In addition, examples of the water-based adhesive include adhesive compositions using a polyvinyl alcohol resin or a urethane resin as a main component.

When the transparent protective layer is a cured product of an active energy ray-curable resin composition, the active energy ray-curable component contained in the composition may be a cationically polymerizable component, a radically polymerizable component, or both of them. Examples of the active energy ray include ultraviolet rays, visible light, electron beams, and X-rays.

In addition, the polarizing plate with an adhesive of the present invention may be: a first transparent protective layer is laminated on one surface of a polarizing plate, and a second transparent protective layer and an adhesive layer are sequentially provided on the other surface of the polarizing plate. As the second transparent protective layer, the layers mentioned as the first transparent protective layer can be used.

(other optical layers)

The polarizing plate with an adhesive of the present invention may be formed by laminating another optical layer having an optical function on the first transparent protective layer as necessary. For example, when the polarizing plate with an adhesive is disposed on the display surface (viewing side) of the image display element, a surface treatment layer such as a hard coat layer, an antireflection layer, or an antiglare layer may be provided on the transparent protective layer. These optical layers correspond to the optical layer 13 shown in fig. 3.

The hard coat layer is formed to prevent scratches on the surface of the polarizing plate, and is formed on the surface of the transparent protective layer by appropriately selecting a substance having excellent adhesion to the transparent protective layer and hardness from ultraviolet-curable resins such as acrylic resins and silicone resins.

The antireflection layer is a layer formed for the purpose of preventing reflection of external light on the surface of the polarizing plate, and can be formed by a known method. The antiglare layer is a layer formed to prevent the visibility from being hindered by reflection of external light on the surface of the polarizing plate, and is generally formed by forming a concave-convex structure on the surface of the transparent protective layer, for example, in such a manner that: a surface roughening method such as a sandblasting method or a printing method, and a method of applying and curing a coating liquid in which transparent fine particles are mixed with an ultraviolet curable resin.

On the other hand, when the polarizing plate is disposed on the opposite side (back side) of the liquid crystal cell from the display surface, a reflective layer, a semi-transmissive reflective layer, a light diffusion layer, a light-collecting plate, a brightness enhancement film, and the like may be stacked on the transparent protective layer. These optical layers correspond to the optical layer 15 shown in fig. 3.

A reflective polarizing plate is used for a liquid crystal display device of a type that reflects external light incident from an observation side to perform display, and since a light source such as a backlight can be omitted, the liquid crystal display device is easily thinned. Further, transflective polarizing plates are used in liquid crystal display devices of a type that performs display in a bright place by reflection and in a dark place by transmission using a light source such as a backlight. The reflective layer for obtaining the reflective polarizing plate can be formed, for example, as follows: a foil or a vapor deposition film containing a metal such as aluminum is attached to the protective layer on the polarizing plate. In addition, the transflective layer for obtaining the transflective polarizing plate may be formed by: a method of making the reflective layer a half mirror, a method of bonding a reflective plate containing pearl pigment and exhibiting light transmittance to a polarizing plate, and the like.

The diffusion-type polarizing plate also has a function of diffusing incident light. The light diffusion layer used for this purpose can be formed by various methods such as a method of applying a matting treatment to the transparent protective layer on the polarizing plate, a method of applying a resin containing fine particles, and a method of adhering a film containing fine particles.

In the polarizing plate for both reflection and diffusion, for example, a diffusion reflection layer may be provided by a method of providing a reflection layer reflecting the uneven structure on the fine uneven structure surface of the diffusion type polarizing plate. The reflective layer having a fine uneven structure has advantages such as diffusing incident light by diffuse reflection, preventing directivity and glare, and suppressing unevenness in brightness and darkness. The resin layer or film containing fine particles has advantages such as diffusing incident light and reflected light thereof when transmitted through the fine particle-containing layer, and further suppressing unevenness in brightness. The reflective layer reflecting the surface fine uneven structure can be formed by directly applying a metal to the surface of the fine uneven structure by a method such as vapor deposition such as vacuum vapor deposition, ion plating, or sputtering, or plating. The fine particles to be blended for forming the fine uneven surface structure may be, for example, inorganic fine particles having an average particle diameter of 0.1 to 30 μm and containing silica, alumina, titania, zirconia, tin oxide, indium oxide, cadmium oxide, antimony oxide, or the like, or organic fine particles containing a crosslinked or non-crosslinked polymer or the like.

The condensing plate is used for controlling an optical path and the like, and may be a prism array sheet, a lens array sheet, a spot attaching sheet, or the like.

The brightness enhancement film is a film having the following functions: the luminance improving film is used for improving the luminance of a liquid crystal display device, and has a function of transmitting a part of incident natural light as linearly polarized light or circularly polarized light and reflecting the rest of the incident natural light for reuse. Examples thereof include: a reflective linear polarization separation sheet in which a plurality of thin films having different refractive index anisotropy are stacked so as to have anisotropic reflectance, a reflective circular polarization separation sheet in which an alignment film of a cholesteric liquid crystal polymer or an alignment liquid crystal layer thereof is supported on a film substrate, or the like.

The above-mentioned various optical layers can be integrated with the transparent protective layer by using a binder or adhesive, and the binder or adhesive used therefor is not particularly limited, and an appropriate one can be selected and used. From the viewpoint of ease of the gluing operation, prevention of occurrence of optical strain, and the like, an adhesive is preferably used. Examples of the pressure-sensitive adhesive include those similar to the pressure-sensitive adhesive layer described above. When the formed pressure-sensitive adhesive layer is exposed on the surface, a release film may be disposed to prevent contamination or the like. As the release film, the same film as described above can be used.

Hereinafter, the polarizing plate with an adhesive according to the present invention will be described with reference to the drawings. Fig. 1 is a schematic cross-sectional view showing an example of a preferable layer structure of the polarizing plate with an adhesive of the present invention. Referring to fig. 1, in a polarizing plate 10 with an adhesive, a first transparent protective layer 3 is stacked on one surface of a polarizer 1, and an adhesive layer 5 is provided on the other surface of the polarizer 1. Further, the adhesive layer 5 is a composition containing a polyether and a salt having an anion containing a fluoro group and a sulfonyl group as an antistatic agent. The general example is as follows: a release film 7 is disposed on the exposed surface of the pressure-sensitive adhesive layer 5, and the surface thereof is temporarily attached and protected until it is bonded to another member.

Fig. 2 is a schematic cross-sectional view showing another example of a preferable layer structure of the polarizing plate with an adhesive according to the present invention. Referring to fig. 2, in the adhesive-attached polarizing plate 10, a first transparent protective layer 3 is stacked on one surface of a polarizer 1, and a second transparent protective layer 4 and an adhesive layer 5 are sequentially disposed on the other surface of the polarizer 1.

For example, as shown in fig. 1, the adhesive-equipped polarizer of the present invention has the following structure to achieve a thin polarizer: a transparent protective layer is laminated on one surface of the polarizing plate, and an adhesive layer is laminated on the other surface. In addition, even in the polarizing plate having the transparent protective layer only on one side as described above, by providing the adhesive layer, the polarizing plate has excellent heat resistance in a high-temperature or high-humidity environment or an environment in which heating and cooling are repeated, and discoloration of the polarizing plate due to transfer of the adhesive component (mainly, an antistatic component) can be suppressed.

As shown in fig. 2, for example, the adhesive-attached polarizing plate of the present invention has the following structure: transparent protective layers are laminated on both surfaces of the polarizing plate, and an adhesive layer is laminated on one of the transparent protective layers. In the polarizing plate having the transparent protective layers on both surfaces in this manner, the adhesive layer is provided, whereby the polarizing plate is excellent in heat resistance under a high-temperature or high-humidity environment or an environment in which heating and cooling are repeated, and discoloration of the polarizing plate due to transfer of the adhesive component can be further suppressed.

The polarizing plate with an adhesive of the present invention can be applied to an image display element such as a liquid crystal cell or a touch panel. Therefore, it is preferable that a release film subjected to a release treatment is laminated on the pressure-sensitive adhesive layer until use.

[ image display element ]

The polarizing plate with an adhesive of the present invention can be disposed in various image display elements to obtain an image display device. Fig. 3 is a schematic cross-sectional view showing an example of a preferable layer structure of the image display device of the present invention.

Referring to fig. 3, polarizing plate with adhesive 10 is bonded to both surfaces of image display element (liquid crystal cell) 20 with adhesive layer 5 exposed through release film 7 (see fig. 1) interposed therebetween. Fig. 3 shows an example in which the polarizing plate with adhesive of the present invention is bonded to both sides of a liquid crystal cell, and the polarizing plates 17 and 19 with adhesive bonded to both sides of the liquid crystal cell may be the same or different.

The polarizing plate with an adhesive of the present invention can be disposed on one surface or both surfaces of a liquid crystal cell to obtain a liquid crystal display device. The liquid crystal cells used may be any of active matrix liquid crystal cells represented by va (vertical alignment), IPS (In-plane Switching), ecb (electric Controlled birefringence), ocb (optical Compensated birefringence), etc., simple matrix liquid crystal cells represented by stn (super-Controlled birefringence), etc., or static drive liquid crystal cells represented by tn (Twisted nematic) mode, etc., and various liquid crystal panels can be used to form a liquid crystal display device represented by these liquid crystal cells. When the polarizing plates with adhesive of the present invention are provided on both sides of the liquid crystal cell, they may be the same or different.

The polarizing plate with an adhesive of the present invention can be effectively used in a circular polarization mode or an elliptical polarization mode having an antireflection function in an image display device other than a liquid crystal display device, for example, a flat panel display such as an organic EL display device. When the image display element is an organic EL display element, it is understood by those skilled in the art that the polarizing plate of the present invention may be bonded to one surface, that is, the viewing-side display surface. Needless to say, the image display device to which the polarizing plate with an adhesive of the present invention is applied is not limited to the polarizing plate exemplified herein.

Examples

The features of the present invention will be described in more detail below with reference to examples and comparative examples. The materials, the amounts used, the ratios, the contents of the treatments, the procedures of the treatments and the like shown in the following examples can be appropriately modified without departing from the gist of the present invention. Therefore, the scope of the present invention is not to be interpreted in a limiting manner by the specific examples shown below. In the examples, "part(s)" and "%" may be "part(s) by weight" and "% by weight", respectively, unless otherwise specified.

Production example 1: preparation of acrylic resin A

In a reaction vessel equipped with a condenser, a nitrogen inlet, a stirrer and a thermometer, 80 parts of ethyl acetate were added, 65 parts of butyl acrylate, 30 parts of 2-ethylhexyl acrylate and 5 parts of 2-hydroxyethyl acrylate as monomer components were added, and the internal temperature was raised to 55 ℃ while introducing nitrogen so as to exclude oxygen. Then, 0.06 parts of azobisisobutyronitrile (polymerization initiator) was dissolved in 10 parts of ethyl acetate, and the entire amount of the resulting solution was added. Then, after stirring for 12 hours while maintaining the temperature, the polymerization reaction was stopped by cooling, thereby producing an acrylic resin a. The weight average molecular weight Mw of the acrylic resin a in terms of polystyrene based on GPC was 150 ten thousand.

Production example 2: preparation of acrylic resin B

In a reaction vessel equipped with a condenser, a nitrogen inlet, a stirrer and a thermometer, 80 parts of ethyl acetate were added, and 71 parts of butyl acrylate, 24 parts of methyl acrylate, 4 parts of 2-hydroxyethyl acrylate and 1 part of acrylic acid as monomer components were added, and nitrogen gas was filled so as to exclude oxygen, and the internal temperature was raised to 55 ℃. Then, 0.06 parts of azobisisobutyronitrile (polymerization initiator) was dissolved in 10 parts of ethyl acetate, and the entire amount of the resulting solution was added. Then, after stirring for 12 hours while maintaining the temperature, the polymerization reaction was stopped by cooling, thereby producing an acrylic resin B. The weight average molecular weight Mw of the acrylic resin B in terms of polystyrene based on GPC was 151 ten thousand.

Production example 3: preparation of acrylic resin C

In a reaction vessel equipped with a condenser, a nitrogen inlet, a stirrer and a thermometer, 80 parts of ethyl acetate were added, 71 parts of butyl acrylate, 24 parts of methyl acrylate and 5 parts of 2-hydroxyethyl acrylate as monomer components were added, and the internal temperature was raised to 55 ℃ while introducing nitrogen so as to exclude oxygen. Then, 0.06 parts of azobisisobutyronitrile (polymerization initiator) was dissolved in 10 parts of ethyl acetate, and the entire amount of the resulting solution was added. Then, after stirring for 12 hours while maintaining the temperature, the polymerization reaction was stopped by cooling, thereby producing an acrylic resin C. The weight average molecular weight Mw of the acrylic resin C in terms of polystyrene based on GPC was 151 ten thousand.

Production example 4: preparation of acrylic resin D

In a reaction vessel equipped with a condenser, a nitrogen inlet, a stirrer and a thermometer, 80 parts of ethyl acetate were added, and 71 parts of butyl acrylate, 24 parts of methyl acrylate, 4.93 parts of 2-hydroxyethyl acrylate and 0.07 part of acrylic acid as monomer components were added, and while nitrogen was sealed so as to exclude oxygen, the internal temperature was raised to 55 ℃. Then, 0.06 parts of azobisisobutyronitrile (polymerization initiator) was dissolved in 10 parts of ethyl acetate, and the entire amount of the resulting solution was added. Then, after stirring for 12 hours while maintaining the temperature, the polymerization reaction was stopped by cooling, thereby producing an acrylic resin D. The weight average molecular weight Mw of the acrylic resin D in terms of polystyrene based on GPC was 150 ten thousand.

Production example 5: preparation of acrylic resin E

In a reaction vessel equipped with a condenser, a nitrogen inlet, a stirrer and a thermometer, 80 parts of ethyl acetate were added, and 71 parts of butyl acrylate, 24 parts of methyl acrylate, 4.85 parts of 2-hydroxyethyl acrylate and 0.15 part of acrylic acid as monomer components were added, and while nitrogen was sealed so as to exclude oxygen, the internal temperature was raised to 55 ℃. Then, 0.06 parts of azobisisobutyronitrile (polymerization initiator) was dissolved in 10 parts of ethyl acetate, and the entire amount of the resulting solution was added. Then, after stirring for 12 hours while maintaining the temperature, the polymerization reaction was stopped by cooling to prepare an acrylic resin system E. The polymerization average molecular weight Mw of the acrylic resin E in terms of polystyrene based on GPC was 150 ten thousand.

Regarding the weight average molecular weights Mw of the acrylic resins prepared above, samples dissolved in THF (tetrahydrofuran) were measured by GPC (gel permeation chromatography).

Production example 6: production of polarizing plate 1

A polyvinyl alcohol film having a thickness of 75 μm (trade name "Kruaray vinyl on VF-PS # 7500" available from Coli, Ltd.) was uniaxially stretched to about 5 times by dry stretching, and then immersed in pure water at 60 ℃ for 1 minute while maintaining the tension, and then immersed in an aqueous solution having a weight ratio of iodine/potassium iodide/water of 0.05/5/100 at 28 ℃ for 60 seconds. Then, the plate was immersed in an aqueous solution having a weight ratio of potassium iodide/boric acid/water of 8.5/8.5/100 at 72 ℃ for 300 seconds. Then, the substrate was washed with pure water at 26 ℃ for 20 seconds and dried at 65 ℃ to obtain a polarizing plate having a thickness of 28 μm and an iodine-oriented layer adsorbed on the polyvinyl alcohol film. When the degree of polarization Py and the transmittance Ty of the polarizing plate were measured using a spectrophotometer (product name "V-7100" of japan spectro corporation), Py was 99.995% and Ty was 42.6%. Then, an epoxy adhesive a was applied to one surface of the polarizer, and a triacetyl cellulose film (TAC) (trade name "KC 4 UY" obtained from konica minolta optical corporation) having a thickness of 40 μm was laminated as a transparent protective layer to prepare a polarizing plate 1. The epoxy adhesive A is obtained by the following steps: to 100 parts of water was dissolved 3 parts of carboxyl-modified polyvinyl alcohol (trade name "KL-318" available from Coli, Ltd.), and 1.5 parts of a polyamide epoxy additive (trade name "sumirez resin (registered trademark) 650 (30)" available from Takago chemical industry Co., Ltd., aqueous solution having a solid content of 30%) was added as a water-soluble epoxy resin to the obtained aqueous solution.

Production example 7: production of polarizing plate 2

A polyvinyl alcohol aqueous solution was applied to a base film (a polypropylene film having a melting point of 163 ℃ C. and a thickness of 110 μm) and dried to prepare a laminated film as a material for producing a polarizing plate. Then, acetoacetyl-modified polyvinyl alcohol powder having an average polymerization degree of 1,100 and a saponification degree of 99.5 mol% (trade name "ゴ - セフアイマ -a (registered trademark) Z-200" available from Nippon synthetic chemical industry Co., Ltd.) was dissolved in hot water at 95 ℃ to prepare a 3% aqueous solution.

To this aqueous solution, a water-soluble polyamide epoxy resin (an aqueous solution having a solid content concentration of 30%, which is available under the trade name "sumirez resin (registered trademark) 650" from takawa chemical industry, ltd.) as a crosslinking agent was mixed at a ratio of 5 parts per 6 parts of the solid content of polyvinyl alcohol to obtain a coating liquid for a primer. Then, the coated surface of the base film containing polypropylene was subjected to corona treatment, and a coating liquid for a primer was applied to the corona-treated surface by a micro-gravure coater, followed by drying at 80 ℃ for 10 minutes to form a primer layer having a thickness of 0.2 μm. Then, a polyvinyl alcohol powder having an average polymerization degree of 2,400 and a saponification degree of 98.0 to 99.0 mol% (trade name "PVA 124" available from Coli, Ltd.) was dissolved in hot water at 95 ℃ to prepare an aqueous polyvinyl alcohol solution having a concentration of 8%. The obtained aqueous solution was applied to the primer layer of the substrate film at room temperature using a die lip coater, and dried at 80 ℃ for 20 minutes to produce a laminated film including the substrate film/primer layer/polyvinyl alcohol layer. This laminated film was uniaxially stretched in the free-end longitudinal direction at a temperature of 160 ℃ by 5.8 times to obtain a laminated stretched film. The overall thickness of the laminated stretched film was 28.5 μm, and the thickness of the polyvinyl alcohol layer was 4.2 μm.

The stretched laminated film was immersed in an aqueous solution having a weight ratio of water/iodine/potassium iodide of 100/0.35/10 at 26 ℃ for 90 seconds to be dyed, and then washed with pure water at 10 ℃. Then, the laminated film was immersed in an aqueous solution having a weight ratio of water/boric acid/potassium iodide of 100/9.5/5 at 76 ℃ for 300 seconds to crosslink polyvinyl alcohol. Then, the plate was washed with pure water at 10 ℃ for 10 seconds, and finally dried at 80 ℃ for 200 seconds. In the above-described manner, a polarizing laminate film in which a polarizing plate including a polyvinyl alcohol layer having iodine adsorbed and oriented was formed on a polypropylene base film was produced. The same epoxy adhesive a as used in production example 6 was applied to the surface (polarizing plate surface) of the polarizing laminate film opposite to the base film, and a triacetyl cellulose film (TAC) (trade name "KC 4 UY" obtained from konica minolta optical corporation) having a thickness of 40 μm as a transparent protective layer was laminated thereto, and then only the base film was peeled off to produce a polarizing plate 2 including a TAC/polyvinyl alcohol polarizer. The polarization degree Py and the transmittance Ty of the polarizing plate 2 were measured using a spectrophotometer (product name "V-7100" of japan spectro corporation), and Py was 99.995% and Ty was 41.9%.

Polarizing plates with adhesives were produced using these polarizing plates. In the following examples and comparative examples, the following antistatic agents were used as the antistatic agents to be added to the pressure-sensitive adhesive compositions for forming the pressure-sensitive adhesive layers.

< antistatic agent >

Antistatic agent 1: a composition was prepared by mixing 100 parts of the polyether ester obtained by mixing 100 parts of DIC (trade name: モノサイザ -W-262) having the structure of formula (II) and ポリサイザ -W-230-H having the structure of formula (I) at a ratio of 1: 1, and dissolving 20 parts of lithium bis (trifluoromethanesulfonyl) imide. The following table 1 shows "antistatic agent 1".

Antistatic agent 2: 50 parts of lithium bis (trifluoromethanesulfonyl) imide was dissolved in 50 parts of polyalkylene glycol (di/mono) alkyl ether. The following table 2 shows "antistatic agent 2".

Ionic compound 1: n-hexyl-4-methylpyridinium hexafluorophosphate, solid (25 ℃). The following tables 1 and 2 are referred to as "ionic compound 1".

Ionic compound 2: glycidyl trimethyl ammonium triflate, liquid (25 ℃). The following tables 1 and 2 are referred to as "ionic compound 2".

Ionic compound 3: 1-decyl-3-methylimidazolium hexafluorophosphate, solid (25 ℃). The following tables 1 and 2 are referred to as "ionic compound 3".

[ example 1]

(preparation of acrylic adhesive solution)

An acrylic pressure-sensitive adhesive solution was prepared by adding 0.1 part of xylylene diisocyanate (product name "Takenate (registered trademark) 500" available from mitsui chemical corporation) and 0.1 part of 3-glycidoxypropylmethoxysilane (product name "KBM-403" available from shin-Etsu chemical corporation) as crosslinking agents to 100 parts of the solid content of the acrylic resin a prepared in preparation example 1, adding 2.5 parts of an antistatic agent 1 as an antistatic agent, and diluting the mixture with ethyl acetate so that the solid content concentration became 15%.

(preparation of adhesive sheet)

The acrylic pressure-sensitive adhesive solution was applied to the surface of a release agent layer having a thickness of 38 μm and a release agent layer treated with a silicone release agent, the release agent layer having a dried coating amount of 20 μm/m²The coating was uniformly applied by a coater, and the resultant was dried in an air circulation type constant temperature oven at 100 ℃ for 3 minutes to form an adhesive layer on the surface of the spacer film. Then, a spacer film having a thickness of 38 μm [ obtained from prince f-tex (Ltd.) ] was bonded to the surface of the pressure-sensitive adhesive layerProduct name "38 RL-07 (L)", an adhesive sheet having a separator film/adhesive layer/separator film configuration was obtained in which the adhesive layer was held by 1 pair of separator films having a poor peeling force. The adhesive sheet was cured at a temperature of 23 ℃ and a relative humidity of 50% for 7 days.

(preparation of polarizing plate with adhesive)

The spacer film having the release agent layer with a low release force was peeled from the cured adhesive sheet, and the exposed adhesive layer was directly transferred (attached) to the polarizing plate side of the polarizing plate 1 obtained in production example 6, thereby producing an adhesive-attached polarizing plate.

[ example 2]

An acrylic binder solution was prepared in the same manner as in example 1, except that an acrylic resin B was used instead of the acrylic resin a used in example 1. Then, an adhesive sheet and an adhesive-attached polarizing plate were produced in the same manner as in example 1 using the acrylic adhesive solution.

[ example 3]

An acrylic binder solution was prepared in the same manner as in example 1, except that an acrylic resin C was used instead of the acrylic resin a used in example 1. Then, an adhesive sheet and an adhesive-attached polarizing plate were produced in the same manner as in example 1 using the acrylic adhesive solution.

[ example 4]

An acrylic binder solution was prepared in the same manner as in example 1, except that an acrylic resin D was used instead of the acrylic resin a used in example 1. Then, an adhesive sheet and an adhesive-attached polarizing plate were produced in the same manner as in example 1 using the acrylic adhesive solution.

[ example 5]

An acrylic adhesive solution was prepared and an adhesive sheet was produced in the same manner as in example 1. A polarizing plate with an adhesive was produced in the same manner as in example 1, except that the polarizing plate 2 obtained in production example 7 was used.

[ example 6]

An acrylic pressure-sensitive adhesive solution was prepared in the same manner as in example 1, except that the antistatic agent 2 was used.

Then, an adhesive sheet and an adhesive-attached polarizing plate were produced in the same manner as in example 1 using the acrylic adhesive solution.

[ example 7]

An acrylic binder solution was prepared in the same manner as in example 6, except that an acrylic resin B was used instead of the acrylic resin a used in example 6. Then, an adhesive sheet and an adhesive-attached polarizing plate were produced in the same manner as in example 6 using the acrylic adhesive solution.

[ example 8]

An acrylic binder solution was prepared in the same manner as in example 6, except that an acrylic resin C was used instead of the acrylic resin a used in example 6. Then, an adhesive sheet and an adhesive-attached polarizing plate were produced in the same manner as in example 6 using the acrylic adhesive solution.

[ example 9]

An acrylic binder solution was prepared in the same manner as in example 6, except that an acrylic resin D was used instead of the acrylic resin a used in example 6. Then, an adhesive sheet and an adhesive-attached polarizing plate were produced in the same manner as in example 6 using the acrylic adhesive solution.

Comparative example 1

An acrylic pressure-sensitive adhesive solution was obtained in the same manner as in example 1, except that the ionic compound 1 as an antistatic agent was used. Then, an adhesive sheet and an adhesive-attached polarizing plate were produced in the same manner as in example 1 using the acrylic adhesive solution.

Comparative example 2

An acrylic pressure-sensitive adhesive solution was obtained in the same manner as in example 1, except that the ionic compound 2 as an antistatic agent was used. Then, an adhesive sheet and an adhesive-attached polarizing plate were produced in the same manner as in example 1 using the acrylic adhesive solution.

Comparative example 3

An acrylic pressure-sensitive adhesive solution was obtained in the same manner as in example 2, except that the ionic compound 3 as an antistatic agent was used. Then, an adhesive sheet and an adhesive-attached polarizing plate were produced in the same manner as in example 1 using the acrylic adhesive solution.

Comparative example 4

An acrylic pressure-sensitive adhesive solution was obtained in the same manner as in example 3, except that the ionic compound 3 as an antistatic agent was used. Then, an adhesive sheet and an adhesive-attached polarizing plate were produced in the same manner as in example 1 using the acrylic adhesive solution.

Comparative example 5

An acrylic pressure-sensitive adhesive solution was obtained in the same manner as in example 4, except that the ionic compound 3 as an antistatic agent was used. Then, an adhesive sheet and an adhesive-attached polarizing plate were produced in the same manner as in example 1 using the acrylic adhesive solution.

Comparative example 6

An acrylic pressure-sensitive adhesive solution was prepared and a pressure-sensitive adhesive sheet was produced in the same manner as in example 1, except that the ionic compound 1 as an antistatic agent was used. A polarizing plate with an adhesive was produced in the same manner as in example 5 using the polarizing plate 2 obtained in production example 7.

Comparative example 7

An acrylic pressure-sensitive adhesive solution was prepared in the same manner as in example 6, except that the ionic compound 1 as an antistatic agent was used. Then, an adhesive sheet and an adhesive-attached polarizing plate were produced in the same manner as in example 6 using the acrylic adhesive solution.

Comparative example 8

An acrylic pressure-sensitive adhesive solution was prepared in the same manner as in example 6, except that the ionic compound 2 as an antistatic agent was used. Then, an adhesive sheet and an adhesive-attached polarizing plate were produced in the same manner as in example 6 using the acrylic adhesive solution.

Comparative example 9

An acrylic pressure-sensitive adhesive solution was obtained in the same manner as in example 8, except that the ionic compound 3 as an antistatic agent was used. Then, an adhesive sheet and an adhesive-attached polarizing plate were produced in the same manner as in example 6 using the acrylic adhesive solution.

Comparative example 10

An acrylic pressure-sensitive adhesive solution was obtained in the same manner as in example 9, except that the ionic compound 3 as an antistatic agent was used. Then, an adhesive sheet and an adhesive-attached polarizing plate were produced in the same manner as in example 1 using the acrylic adhesive solution.

[ reference example 1]

An acrylic pressure-sensitive adhesive solution was obtained in the same manner as in example 1, except that the antistatic agent 1 used in example 1 was not added. Using the acrylic adhesive solution, an adhesive sheet and an adhesive-attached polarizing plate were produced in the same manner as in example 1.

[ reference example 2]

An acrylic pressure-sensitive adhesive solution was obtained in the same manner as in example 1, except that the acrylic resin E was used instead of the acrylic resin a used in example 1, and the antistatic agent 1 used in example 1 was not added. Using the acrylic adhesive solution, an adhesive sheet and an adhesive-attached polarizing plate were produced in the same manner as in example 1.

[ reference example 3]

An acrylic pressure-sensitive adhesive solution was obtained in the same manner as in example 6, except that the antistatic agent 2 used in example 6 was not added. An adhesive sheet and an adhesive-attached polarizing plate were produced in the same manner as in example 6 using the acrylic adhesive solution.

[ reference example 4]

An acrylic pressure-sensitive adhesive solution was obtained in the same manner as in example 6, except that the acrylic resin E was used instead of the acrylic resin a used in example 6, and the antistatic agent 2 used in example 6 was not added. An adhesive sheet and an adhesive-attached polarizing plate were produced in the same manner as in example 6 using the acrylic adhesive solution.

The polarizing plates with adhesives prepared above were used to perform the following evaluations. The results of examples 1 to 5, comparative examples 1 to 6, and reference examples 1 and 2 are shown in Table 1, and the results of examples 6 to 9, comparative examples 7 to 10, and reference examples 3 and 4 are shown in Table 2.

[ evaluation ]

< measurement of surface resistance value >

After the separator film of the adhesive-attached polarizing plate cut to 100mm × 100mm was peeled off, the sheet was measured using a resistance value measuring instrument (trade name "Hiresta-UP" (Hiresta is a registered trademark) model number: MCP-HT 450' ], the surface resistance value (omega/□) of the adhesive surface was measured.

< evaluation of durability of polarizing plate >

After the spacer film of the polarizing plate with the adhesive was peeled off, one surface of alkali-free glass (trade name "EAGLEXG (registered trademark)", manufactured by corning corporation) having a thickness of 0.7mm was bonded to the adhesive surface to prepare an optical laminate. Then, the polarizing plate with the adhesive was completely adhered to glass by a high-pressure autoclave treatment at 50 ℃ and 0.5MPa for 20 minutes, thereby producing an optical laminate. The optical laminate prepared in the above was treated in a constant temperature and humidity chamber at 85 ℃ (heat resistance test) for 500 hours, and the optical laminate after the test was visually observed.

(evaluation criteria)

O: no changes in appearance such as floating, peeling, and foaming were observed.

And (delta): slight changes in appearance such as floating, peeling, foaming, etc. were noted.

X: the appearance changes such as floating, peeling, foaming and the like are obviously seen.

< evaluation of optical durability (transmitted color tone) >

After the spacer film of the polarizing plate with an adhesive was peeled off, an optical laminate was produced by bonding the adhesive surface to one surface of alkali-free glass (trade name "EAGLEXG (registered trademark)", manufactured by corning corporation) having a thickness of 0.7 mm. Then, the resulting mixture was subjected to a high-pressure autoclave treatment at 50 ℃ under 0.5MPa for 20 minutes to completely bond the polarizing plate with an adhesive to glass, thereby preparing an optical laminate, and the transmission color b was measured^*The value is obtained. Then, the optical laminate was placed in a constant temperature and humidity chamber at a temperature of 60 ℃ and a relative humidity of 9After 0% (wet heat resistance test) for 100 hours, the transmitted color tone b was measured^*The value is obtained. Here, b^*Is L^*a^*b^*The color values represented by the color system. The measurement was carried out using a spectrocolorimeter [ product name "SE 6000" of Nippon Denshoku industries Co., Ltd.). Using the measured value, the change amount Δ b of the transmitted color tone before and after the test was calculated^*The value is obtained.

Δb^*Post-test assay-pre-test assay

< determination of degree of polarization >

After the spacer film of the polarizing plate with an adhesive was peeled off, an optical laminate was produced by bonding the adhesive surface to one surface of alkali-free glass (trade name "EAGLEXG (registered trademark)", manufactured by corning corporation) having a thickness of 0.7 mm. Then, the polarizing plate with the adhesive was completely adhered to glass by a high-pressure autoclave treatment at 50 ℃ and 0.5MPa for 20 minutes, thereby producing an optical laminate. The optical laminate prepared as described above was treated at 60 ℃ and 90% relative humidity (wet heat resistance test) for 100 hours, and the polarization degree Py of the polarizing plate before and after the treatment for 100 hours was measured using a spectrophotometer [ product name "V-7100" of japan spectro (ltd.) ], and the change amount Δ Py was calculated.

Δ Py ═ value (measured after treatment) - (initial value)

< confirmation of color change based on visual observation >)

After the spacer film of the polarizing plate with an adhesive was peeled off, an optical laminate was produced by bonding the adhesive surface to one surface of alkali-free glass (trade name "EAGLEXG (registered trademark)", manufactured by corning corporation) having a thickness of 0.7 mm. Then, the polarizing plate with the adhesive was completely adhered to glass by a high-pressure autoclave treatment at 50 ℃ and 0.5MPa for 20 minutes, thereby producing an optical laminate. The optical laminate prepared in the above was treated in a constant temperature and humidity chamber at 60 ℃ and 90% relative humidity (wet heat resistance test) for 500 hours, and the presence or absence of color change was visually confirmed.

[ Table 1]

[ Table 2]

As is clear from the results shown in tables 1 and 2, in examples 1 to 9 satisfying the specification of the present invention, the surface resistance value of the pressure-sensitive adhesive layer was sufficiently small, and the optical durability was excellent in addition to the polarizer durability.

That is, in any of the examples, even when left under a high-humidity and high-heat environment for a long time, the change in color tone (deterioration of the polarizing plate) was sufficiently suppressed, and the amount of change in the degree of polarization was small, and a high degree of polarization was maintained. On the other hand, it is clear that comparative examples 1 to 10, which deviate from the definition of the present invention, are all low in optical durability. In particular, in comparative examples 1 and 2, the polarizing plate had low durability and had poor function as a polarizing plate. Further, as is clear from comparison between the reference examples and the examples, the antistatic agent defined in the present invention can sufficiently reduce the surface resistance value.

Industrial applicability of the invention

The polarizing plate with an adhesive of the present invention is excellent in durability even under a high-humidity and high-heat environment. In particular, the present invention is useful for various image display devices for portable use in which the module itself is thin and lightweight and durability is improved.

Description of the symbols

A polarizing plate,

The first transparent protective layer,

A second transparent protective layer,

An adhesive layer (with antistatic properties),

A release film (spacer film),

Polarizing plate with adhesive,

The optical layer (viewing side) has,

The optical layer (back side),

A polarizing plate having an adhesive on an observation side,

A polarizing plate having an adhesive on the back surface side,

An image display element (liquid crystal cell).

Claims

1. A polarizing plate with an adhesive, wherein an adhesive layer formed of an adhesive composition containing an antistatic agent is laminated on one surface of a polarizing plate having a thickness of 1 to 28 [ mu ] m,

the polarizing plate is a polarizing plate in which a dichroic dye is adsorbed and oriented on a polyvinyl alcohol resin,

the polarizing plate is in close contact with the adhesive layer,

the antistatic agent contains:

a salt having an anion having a fluoro group and a sulfonyl group, and

at least 1 polyether selected from the group consisting of polyether esters, polyalkylene glycol monoalkyl ethers and polyalkylene glycol dialkyl ethers,

the polyether is a compound shown as the following formula (III),

R⁵(OCH₂CH₂)_nOR⁶(III)

in the formula, R⁵Represents an alkyl group having 1 to 12 carbon atoms, R⁶Represents a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, n represents an integer of 3 to 6,

the anion having a fluoro group and a sulfonyl group is at least 1 anion selected from a bis (fluoroalkylsulfonyl) imide ion, a tris (fluoroalkylsulfonyl) methide ion and a fluoroalkylsulfonic acid ion.

2. The adhesive-attached polarizing plate according to claim 1,

the adhesive composition comprises 100 parts by weight of an acrylic resin (A) and 0.001 to 10 parts by weight of a crosslinking agent (B),

the acrylic resin (A) is a copolymer of a monomer mixture containing at least a (meth) acrylate monomer having an alkyl group with 1 to 18 carbon atoms, and has a weight average molecular weight of 40 to 250 ten thousand.

3. The adhesive-carrying polarizing plate according to claim 2,

the acrylic resin (A) is a copolymer of a monomer mixture containing at least a carboxyl group-containing monomer in addition to a (meth) acrylate monomer having an alkyl group with 1 to 18 carbon atoms.

4. The adhesive-carrying polarizing plate according to claim 2,

the acrylic resin (A) is a copolymer of a monomer mixture containing at least a monomer having 1 olefinic double bond and at least 1 reactive functional group in the molecule in addition to a (meth) acrylate monomer having an alkyl group with 1 to 18 carbon atoms, and the at least 1 reactive functional group does not include a carboxyl group.

5. The adhesive-attached polarizing plate according to any one of claims 1 to 4,

the salt having an anion having a fluoro group and a sulfonyl group is a salt composed of an anion having a fluoro group and a sulfonyl group and any cation selected from the group consisting of an alkali metal ion, a group 2 element ion, a transition metal ion and a amphoteric metal ion.

6. The adhesive-attached polarizing plate according to any one of claims 1 to 4,

the salt having an anion having a fluoro group and a sulfonyl group is at least 1 salt selected from the group consisting of an alkali metal salt of bis (fluoroalkylsulfonyl) imide, an alkali metal salt of tris (fluoroalkylsulfonyl) methide, and an alkali metal salt of trifluoroalkylsulfonic acid.

7. A polarizing plate with an adhesive, wherein,

the adhesive-attached polarizing plate according to any one of claims 1 to 6, wherein a first transparent protective layer is laminated on one surface of the polarizing plate, and the adhesive layer is laminated on the other surface of the polarizing plate.

8. The polarizing plate with adhesive of claim 7,

the first transparent protective layer is laminated on the polarizing plate with an adhesive layer interposed therebetween.

9. The polarizing plate with adhesive of claim 7 or 8,

an optical layer is laminated on a surface of the first transparent protective layer on the side opposite to the polarizing plate.

10. The adhesive-carrying polarizing plate according to any one of claims 1 to 4 or the adhesive-carrying polarizing plate according to claim 7 or 8,

a release film is bonded to the surface of the pressure-sensitive adhesive layer.

11. An image display device, wherein,

the adhesive-attached polarizing plate according to any one of claims 1 to 6 or the adhesive-attached polarizing plate according to any one of claims 7 to 9 is bonded to an image display element with an adhesive layer interposed therebetween.