Pressure-sensitive adhesive layer attached polarizing film and image display

Abstract

A pressure-sensitive adhesive layer attached polarizing film of invention includes a polarizing film; and a pressure-sensitive adhesive layer provided on the polarizing film, wherein the polarizing film comprises a polarizer and a transparent protective film provided on only one side of the polarizer, the pressure-sensitive adhesive layer is provided on a side of the polarizer opposite to the side on which the transparent protective film is provided, and the pressure-sensitive adhesive layer is made from a pressure-sensitive adhesive composition including a (meth)acryl-based polymer (A), an onium-anion salt (B1), and an alkali metal salt (B2). The pressure-sensitive adhesive layer attached polarizing film has a pressure-sensitive adhesive layer possessing an antistatic function and satisfactory durability even after a humidity test under severe conditions and is less prone to degradation of optical properties even after a humidity test under severe conditions.

Claims

1. A pressure-sensitive adhesive layer attached polarizing film, comprising: a polarizing film; and a pressure-sensitive adhesive layer provided on the polarizing film, wherein the polarizing film comprises a polarizer and a transparent protective film provided on only one side of the polarizer, the pressure-sensitive adhesive layer is provided on a side of the polarizer opposite to the side on which the transparent protective film is provided, and the pressure-sensitive adhesive layer is made from a pressure-sensitive adhesive composition consisting of a (meth)acryl-based polymer (A), an onium-anion salt (B1), and more than 0.1 to 5 parts by weight of an alkali metal salt (B2) based on 100 parts by weight of the (meth)acryl-based polymer (A) and optionally at least one component selected from the group consisting of a crosslinking agent (C), a silane coupling agent (D), a polyether-modified silicone compound, a polyether compound of a polyalkylene glycol, a colorant, a pigment, a tackifier, a dye, a surfactant, a plasticizer, a surface lubricant, a leveling agent, a softening agent, a polymerization inhibitor, an inorganic or organic filler, and a redox system including a reducing agent, wherein an anion moiety of the alkali metal salt(B2) is at least one consisting of the group represented by the following general formulae (1) to (1) (CF.sub.nF.sub.2n+1SO.sub.2).sub.2N.sup., wherein n is an integer of 1 to 10;
CF.sub.2(C.sub.mF.sub.2mSO.sub.2).sub.2N.sup.,(2) wherein m is an integer of 1 to 10;
.sup.O.sub.3S(CF.sub.2).sub.lSO.sub.3.sup.,(3) wherein l is an integer of 1 to 10; and
(C.sub.pF.sub.2p+1SO.sub.2)N.sup.(C.sub.qF.sub.2q+1SO.sub.2),(4) wherein p and q are each an integer of 1 to 10.

2. The pressure-sensitive adhesive layer attached polarizing film according to claim 1, wherein the onium-anion salt (B1) is an onium-fluorine-containing imide anion salt.

3. The pressure-sensitive adhesive layer attached polarizing film according to claim 1, wherein the onium of the onium-anion salt (B1) is at least one selected from a nitrogen-containing onium, a sulfur-containing onium, and a phosphorus-containing onium.

4. The pressure-sensitive adhesive layer attached polarizing film according to claim 3, wherein the onium of the onium-anion salt (B1) is at least one selected from ammonium, pyrrolidinium, piperidinium, and sulfonium.

5. The pressure-sensitive adhesive layer attached polarizing film according to claim 4, wherein the onium of the onium-anion salt (B1) is pyrrolidinium.

6. The pressure-sensitive adhesive layer attached polarizing film according to claim 1, wherein the onium of the onium-anion salt (B1) has no unsaturated bond.

7. The pressure-sensitive adhesive layer attached polarizing film according to claim 1, wherein the onium of the onium-anion salt (B1) is an alkyl onium having an alkyl group of 1 to 4 carbon atoms.

8. The pressure-sensitive adhesive layer attached polarizing film according to claim 1, which contains 0.1 to 10 parts by weight of the onium-anion salt (B1) based on 100 parts by weight of the (meth)acryl-based polymer (A).

9. The pressure-sensitive adhesive layer attached polarizing film according to claim 1, wherein the alkali metal of the alkali metal salt (B2) is lithium.

10. The pressure-sensitive adhesive layer attached polarizing film according to claim 1, wherein the polarizer has a thickness of 10 m or less.

11. The pressure-sensitive adhesive layer attached polarizing film according to claim 1, wherein the (meth)acryl-based polymer (A) comprises an alkyl (meth)acrylate monomer unit and a hydroxyl group-containing monomer unit.

12. The pressure-sensitive adhesive layer attached polarizing film according to claim 1, wherein the (meth)acryl-based polymer (A) comprises an alkyl (meth)acrylate monomer unit and a carboxyl group-containing monomer unit.

13. The pressure-sensitive adhesive layer attached polarizing film according to claim 1, wherein the pressure-sensitive adhesive composition comprises the crosslinking agent (C).

14. The pressure-sensitive adhesive layer attached polarizing film according to claim 13, which contains 0.01 to 20 parts by weight of the crosslinking agent (C) based on 100 parts by weight of the (meth)acryl-based polymer (A).

15. The pressure-sensitive adhesive layer attached polarizing film according to claim 13, wherein the crosslinking agent (C) is at least one selected from an isocyanate compound and a peroxide.

16. The pressure-sensitive adhesive layer attached polarizing film according to claim 1, comprising 0.001 to 5 parts by weight of the silane coupling agent (D) based on 100 parts by weight of the (meth)acryl-based polymer (A).

17. The pressure-sensitive adhesive layer attached polarizing film according to claim 1, comprising 0.001 to 10 parts by weight of the polyether-modified silicone compound based on 100 parts by weight of the (meth)acryl-based polymer (A).

18. The pressure-sensitive adhesive layer attached polarizing film according to claim 1, wherein the (meth)acryl-based polymer (A) has a weight average molecular weight of 500,000 to 3,000,000.

19. An image display, comprising at least one piece of the pressure-sensitive adhesive layer attached polarizing film according to claim 1.

Description

EXAMPLES

(1) The invention is more specifically described by the examples below, which are not intended to limit the scope of the invention. In each example, parts and % are all by weight. Unless otherwise stated below, the conditions of room temperature standing are 23 C. and 65% RH in all the cases.

(2) <Measurement of Weight Average Molecular Weight of (Meth)acrylic Polymer (A)>

(3) The weight average molecular weight (Mw) of the (meth)acrylic polymer (A) was measured by GPC (Gel Permeation Chromatography). Analyzer: HLC-8120GPC manufactured by TOSOH CORPORATION Columns: G7000H.sub.XL+GMH.sub.XL+GMH.sub.XL, manufactured by TOSOH CORPORATION Column size: each 7.8 mm30 cm, 90 cm in total Column temperature: 40 C. Flow rate: 0.8 ml/minute Injection volume: 100 l Eluent: tetrahydrofuran Detector: differential refractometer (RI) Standard sample: polystyrene
<Preparation of Polarizing Film (1)>

(4) A process for forming a thin polarizing layer was performed. In the process, a laminate including an amorphous PET substrate and a 9 m thick PVA layer formed thereon was first subjected to auxiliary in-air stretching at a stretching temperature of 130 C. to form a stretched laminate. Subsequently, the stretched laminate was subjected to dyeing to form a colored laminate, and the colored laminate was subjected to stretching in an aqueous boric acid solution at a stretching temperature of 65 C. to a total stretch ratio of 5.94 times, so that an optical film laminate was obtained, which had a 4 m thick PVA layer stretched together with the amorphous PET substrate. Such two-stage stretching successfully formed an optical film laminate having a 4 m thick PVA layer, which was formed on the amorphous PET substrate, contained highly oriented PVA molecules, and formed a highly-functional polarizing layer in which iodine absorbed by the dyeing formed a polyiodide ion complex oriented highly in a single direction. An 40 m thick saponified triacetylcellulose film was further attached to the surface of the polarizing layer of the optical film laminate, while a polyvinyl alcohol-based adhesive was applied to the surface, and then the amorphous PET substrate was peeled off, so that a polarizing film with a thin polarizing layer was obtained. Hereinafter, this is referred to as thin polarizing film (1).

(5) (Preparation of Polarizing Film (2))

(6) An 80 m-thick polyvinyl alcohol film was stretched to 3 times between rolls different in velocity ratio, while it was dyed in a 0.3% iodine solution at 30 C. for 1 minute. The film was then stretched to a total stretch ratio of 6 times, while it was immersed in an aqueous solution containing 4% of boric acid and 10% of potassium iodide at 60 C. for 0.5 minutes. The film was then washed by immersion in an aqueous solution containing 1.5% of potassium iodide at 30 C. for 10 seconds and then dried at 50 C. for 4 minutes to give a polarizer with a thickness of 20 m. Saponified triacetylcellulose films each with a thickness of 40 m was bonded to one side of the polarizer with a polyvinyl alcohol adhesive to form a polarizing film. Hereinafter, this is referred to as ordinary polarizing film (2).

Production Example 1

(7) <Preparation of Acryl-Based Polymer (A-1)>

(8) To a four-neck flask equipped with a stirring blade, a thermometer, a nitrogen gas introducing tube, and a condenser were added a monomer mixture containing 99 parts of butyl acrylate and 1 part of 4-hydroxybutyl acrylate. Based on 100 parts (solid basis) of the monomer mixture, 0.1 parts of 2,2-azobisisobutyronitrile as a polymerization initiator was further added together with ethyl acetate. Nitrogen gas was introduced to replace the air, while the mixture was gently stirred, and then a polymerization reaction was performed for 7 hours, while the temperature of the liquid in the flask was kept at about 60 C. Subsequently, ethyl acetate was added to the resulting reaction liquid to adjust the solids content to 30%, so that a solution of an acryl-based polymer (A-1) with a weight average molecular weight of 1,400,000 was obtained.

Production Example 2

(9) <Preparation of Acryl-Based Polymer (A-2)>

(10) To a four-neck flask equipped with a stirring blade, a thermometer, a nitrogen gas introducing tube, and a condenser were added a monomer mixture containing 99 parts of butyl acrylate, 0.5 parts of 2-hydroxyethyl acrylate and 0.5 parts of acrylic acid. Based on 100 parts (solid basis) of the monomer mixture, 0.1 parts of 2,2-azobisisobutyronitrile as a polymerization initiator was further added together with ethyl acetate. Nitrogen gas was introduced to replace the air, while the mixture was gently stirred, and then a polymerization reaction was performed for 7 hours, while the temperature of the liquid in the flask was kept at about 60 C. Subsequently, ethyl acetate was added to the resulting reaction liquid to adjust the solids content to 30%, so that a solution of an acryl-based polymer (A-2) with a weight average molecular weight of 1,400,000 was obtained.

Example 1

(11) (Preparation of Pressure-Sensitive Adhesive Composition)

(12) Based on 100 parts of the solids of the acryl-based polymer (A-1) solution obtained in Production Example 1, 0.2 parts of ethylmethylpyrrolidinium bis(trifluoromethanesulfonyl)imide (manufactured by Tokyo Chemical Industry Co., Ltd.), 0.2 parts of lithium bis(trifluoromethanesulfonyl)imide (manufactured by Mitsubishi Materials Electronic Chemicals Co., Ltd), 0.1 parts of trimethylolpropane xylylene diisocyanate (Takenate D110N, manufactured by Mitsui Chemicals, Inc.), 0.3 parts of dibenzoyl peroxide, and 0.075 parts of -glycidoxypropylmethoxysilane (KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.) were added to the acryl-based polymer (A-1) solution, so that an acryl-based pressure-sensitive adhesive solution was obtained.

(13) (Preparation of Pressure-Sensitive Adhesive Layer-Attached Polarizing Film

(14) Subsequently, the acryl-based pressure-sensitive adhesive solution was uniformly applied to the surface of a silicone release agent-treated polyethylene terephthalate film (separator film) with a fountain coater, and dried for 2 minutes in an air circulation-type thermostatic oven at 155 C., so that a 20 m thick pressure-sensitive adhesive layer was formed on the surface of the separator film. Subsequently, the pressure-sensitive adhesive layer was transferred from the separator film to the polarizing layer side that is a polarizer of the thin polarizing film (1) prepared as described above, so that a pressure-sensitive adhesive layer-attached polarizing film was obtained.

Examples 2 to 23 and Comparative Examples 1 to 5

(15) Pressure-sensitive adhesive layer-attached polarizing films were prepared as in Example 1, except that in the preparation of the pressure-sensitive adhesive composition, the amount or type of each component were changed as shown in Table 1 and 2 and that in the preparation of the pressure-sensitive adhesive layer-attached polarizing film, the type of the polarizing film was changed as shown in Table 1.

(16) The pressure-sensitive adhesive layer-attached polarizing film obtained in each of the examples and the comparative examples was evaluated as described below. The results of the evaluation are shown in Table 1 and 2.

(17) <Surface Resistance>

(18) After the separator film was peeled off from the pressure-sensitive adhesive layer attached polarizing film, the surface resistance (/square) (initial) of the pressure-sensitive adhesive surface was measured with MCP-HT450 manufactured by Mitsubishi Chemical Analytech Co., Ltd. The pressure-sensitive adhesive layer attached polarizing film was then stored for 48 hours in a thermo-hygrostat under the conditions of 60 C. and 95% RH. After the storage, the surface resistance (after intense humidification) of the pressure-sensitive adhesive surface was also measured in the same way. The surface resistance is preferably 5.010.sup.12 /square or less, more preferably 1.010.sup.12 /square or less.

(19) <Evaluation of Static Electricity-Induced Unevenness>

(20) The prepared pressure-sensitive adhesive layer-attached polarizing film was cut into a piece with a size of 100 mm100 mm, which was bonded to a liquid crystal panel. The panel was placed on a backlight with a brightness of 10,000 cd, and the orientation of the liquid crystal was disturbed using 5 kV static electricity produced by an electrostatic generator, ESD, (ESD-8012A, manufactured by Sanki Electronic Industries Co., Ltd.). The time required for recovery from the orientation failure-induced display failure was measured using an instantaneous multichannel photodetector system (MCPD-3000, manufactured by Otsuka Electronics Co., Ltd.), and evaluated (initial) according to the criteria below.

(21) The pressure-sensitive adhesive layer attached polarizing film was then stored for 48 hours in a thermo-hygrostat under the conditions of 60 C. and 95% RH. After the storage, the pressure-sensitive adhesive layer attached polarizing film was also evaluated (intense humidification) in the same way. : Display failure was eliminated in a time of less than one second. : Display failure was eliminated in a time of one second to less than 10 seconds. x: Display failure was eliminated in a time of 10 seconds or more.
<Durability>

(22) The separator film was peeled off from the pressure-sensitive adhesive layer-attached polarizing film, and the polarizing film was bonded to a 0.7 mm thick non-alkali glass plate (1737, manufactured by Corning Incorporated) using a laminator. Subsequently, the laminate was autoclaved at 50 C. and 5 atm for 15 minutes, so that the pressure-sensitive adhesive layer-attached polarizing film was completely bonded to the non-alkali glass plate. Subsequently, the laminate was stored in a heating oven at 85 C. (heating) and stored in a thermo-hygrostat under the conditions of 60 C./95% RH (intense humidification), respectively, and after 500 hours, the presence or absence of peeling of the polarizing film was evaluated according to the criteria below. : No peeling was detected at all. : Peeling was detected at an invisible level. : Visible small peeling was detected. x: Significant peeling was detected.
<Measurement of Degree of Polarization>

(23) The separator film was peeled off from the pressure-sensitive adhesive layer-attached polarizing film, and the polarizing film was bonded to a 0.7 mm thick non-alkali glass plate (1737, manufactured by Corning Incorporated) using a laminator. Subsequently, the laminate was autoclaved at 50 C. and 0.5 MPa for 15 minutes, so that the pressure-sensitive adhesive layer-attached polarizing film was completely bonded to the non-alkali glass plate. Subsequently, the laminate was stored in a thermo-hygrostat under the conditions of 60 C./90% RH (humidification), and stored in a thermo-hygrostat under the conditions of 60 C./95% RH (intense humidification), respectively, for 500 hours. Before and after the storage, the degree of polarization of the polarizing film was measured with V-7100 manufactured by JASCO Corporation, and then the change P in the degree of polarization=(the degree of polarization before the storage)(the degree of polarization after the storage) was calculated. After any of the humidification and the intense humidification, the change P should preferably be less than 0.15, more preferably 0.05 or less.

(24) TABLE-US-00001 TABLE 1 Evaluations Polarizing film Static Po- Pressure-sensitive adhesive composition electricity- Polarization lar- (Meth) Onium- Alkali Crosslinking Silane Surface resistance induced degree izer acryl- anion metal agent (C) coupling Additional (/square) unevenness Durability reduction P thick- based salt salt Isocyanate agent compound Intense Intense Intense Intense ness polymer (A) (B1) (B2) compound Peroxide (D) (E) humidi- humidi- humidi- Humidi- humidi- Type (m) Type Parts Type Parts Type Parts Type Parts Type Parts Type Parts Type Parts Initial fication Initial fication Heating fication fication fication Example 1 Thin polarizing 4 A-1 100 B1-1 0.2 B2-1 0.2 C-1 0.1 C-2 0.3 D-1 0.075 2.0E+12 2.2E+12 0.01 0.02 film (1) Example 2 Thin polarizing 4 A-1 100 B1-1 0.5 B2-1 0.2 C-1 0.1 C-2 0.3 D-1 0.075 7.9E+11 8.7E+11 0.01 0.02 film (1) Example 3 Thin polarizing 4 A-1 100 B1-1 1 B2-1 0.2 C-1 0.1 C-2 0.3 D-1 0.075 2.0E+11 2.2E+11 0.01 0.02 film (1) Example 4 Thin polarizing 4 A-1 100 B1-1 4 B2-1 0.2 C-1 0.1 C-2 0.3 D-1 0.075 5.8E+09 6.3E+09 0.01 0.02 film (1) Example 5 Thin polarizing 4 A-1 100 B1-1 7 B2-1 0.2 C-1 0.1 C-2 0.3 D-1 0.075 3.1E+09 3.4E+09 0.01 0.02 film (1) Example 6 Thin polarizing 4 A-1 100 B1-1 1 B2-1 0.02 C-1 0.1 C-2 0.3 D-1 0.075 2.0E+11 2.2E+11 0.02 0.07 film (1) Example 7 Thin polarizing 4 A-1 100 B1-1 1 B2-1 0.05 C-1 0.1 C-2 0.3 D-1 0.075 2.0E+11 2.2E+11 0.02 0.05 film (1) Example 8 Thin polarizing 4 A-1 100 B1-1 1 B2-1 0.1 C-1 0.1 C-2 0.3 D-1 0.075 2.0E+11 2.2E+11 0.01 0.02 film (1) Example 9 Thin polarizing 4 A-1 100 B1-1 1 B2-1 0.5 C-1 0.1 C-2 0.3 D-1 0.075 2.0E+11 2.2E+11 0.01 0.02 film (1) Example Thin polarizing 4 A-1 100 B1-1 1 B2-1 1 C-1 0.1 C-2 0.3 D-1 0.075 8.1E+10 8.9E+10 0.01 0.02 10 film (1) Example Thin polarizing 4 A-1 100 B1-1 1 B2-1 4 C-1 0.1 C-2 0.3 D-1 0.075 2.1E+10 2.3E+10 0.01 0.02 11 film (1) Example Thin polarizing 4 A-2 100 B1-1 1 B2-1 0.2 C-1 0.1 C-2 0.3 D-1 0.075 2.0E+11 3.4E+11 0.06 0.07 12 film (1) Example Thin polarizing 4 A-1 100 B1-1 1 B2-1 0.2 C-1 0.1 C-2 0.3 D-1 0.075 E-1 0.5 2.1E+11 2.3E+11 0.01 0.02 13 film (1) Example Normal polarizing 20 A-1 100 B1-1 1 B2-1 0.2 C-1 0.1 C-2 0.3 D-1 0.075 2.1E+11 2.3E+11 0.01 0.02 14 film (2) Example Thin polarizing 4 A-1 100 B1-1 1 B2-1 0.2 C-1 0.2 D-1 0.075 2.0E+11 2.1E+11 0.01 0.02 15 film (1) Example Thin polarizing 4 A-1 100 B1-1 1 B2-1 0.2 C-1 0.1 C-2 0.3 2.0E+11 2.2E+11 0.01 0.02 16 film (1) Example Thin polarizing 4 A-1 100 B1-1 1 B2-1 1 C-1 0.1 C-2 0.3 D-1 0.075 E-2 0.5 2.1E+11 2.3E+11 0.02 0.05 17 film (1) Compar- Thin polarizing 4 A-1 100 C-1 0.1 C-2 0.3 D-1 0.075 >10.sup.13 >10.sup.13 X X 0.01 0.02 ative film (1) Example 1 Compar- Thin polarizing 4 A-1 100 B1-1 1 C-1 0.1 C-2 0.3 D-1 0.075 2.0E+11 2.2E+11 0.02 0.08 ative film (1) Example 2 Compar- Thin polarizing 4 A-1 100 B2-1 0.2 C-1 0.1 C-2 0.3 D-1 0.075 3.3E+12 8.7E+12 X 0.01 0.02 ative film (1) Example 3 Compar- Thin polarizing 4 A-1 100 B2-1 1 C-1 0.1 C-2 0.3 D-1 0.075 2.3E+11 5.3E+13 X 0.01 0.02 ative film (1) Example 4 B1-1 Ethylmethylpyrrolidinium bis(trifluoromethanesulfonyl)imide manufactured by Tokyo Chemical Industry Co., Ltd. B2-1 Lithium bis(trifluoromethanesulfonyl)imide manufactured by Mitsubishi Materials Electronic Chemicals Co., Ltd. E-1 SILYL SAT10 (4,000 in number average molecular weight) manufactured by Kaneka Corporation E-2 Polypropylene glycol (5,000 in number average molecular weight) manufactured by Wako Pure Chemical Industries, Ltd.

(25) TABLE-US-00002 TABLE 2 Pressure-sensitive adhesive composition Polarizing (Meth) Onium- Alkali Crosslinking Silane film acryl- anion metal agent (C) coupling Additional Polarizer based salt salt Isocyanate agent compound thickness polymer (A) (B1) (B2) compound Peroxide (D) (E) Type (m) Type Parts Type Parts Type Parts Type Parts Type Parts Type Parts Type Parts Example 18 Thin polarizing 4 A-1 100 B1-2 1 B2-1 0.2 C-1 0.1 C-2 0.3 D-1 0.075 film (1) Example 19 Thin polarizing 4 A-1 100 B1-3 1 B2-1 0.2 C-1 0.1 C-2 0.3 D-1 0.075 film (1) Example 20 Thin polarizing 4 A-1 100 B1-4 1 B2-1 0.2 C-1 0.1 C-2 0.3 D-1 0.075 film (1) Example 21 Thin polarizing 4 A-1 100 B1-5 1 B2-1 0.2 C-1 0.1 C-2 0.3 D-1 0.075 film (1) Example 22 Thin polarizing 4 A-1 100 B1-6 1 B2-1 0.2 C-1 0.1 C-2 0.3 D-1 0.075 film (1) Example 23 Thin polarizing 4 A-1 100 B1-1 1 B2-2 0.2 C-1 0.1 C-2 0.3 D-1 0.075 film (1) Comparative Thin polarizing 4 A-1 100 B1-6 1 C-1 0.1 C-2 0.3 D-1 0.075 Example 5 film (1) Evaluations Surface resistance Static electricity- Polarization (/square) induced unevenness degree Intense Intense Durability reduction P Initial humidification Initial humidification Heating Intense humidification Humidification Intense humidification Example 18 2.1E+11 2.3E+11 0.01 0.03 Example 19 2.4E+11 2.7E+11 0.01 0.05 Example 20 2.3E+11 2.6E+11 0.01 0.05 Example 21 2.1E+11 2.3E+11 0.06 0.08 Example 22 2.1E+11 2.3E+11 0.10 0.13 Example 23 2.0E+11 2.2E+11 0.05 0.07 Comparative 2.1E+11 2.3E+11 0.12 0.15 Example 5 B1-1 Ethylmethylpyrrolidinium bis(trifluoromethanesulfonyl)imide manufactured by Tokyo Chemical Industry Co., Ltd. B1-2 Methylpropylpyrrolidinium bis(trifluoromethanesulfonyl)imide manufactured by Tokyo Chemical Industry Co., Ltd. B1-3 Trimethylpropylammonium bis(trifluoromethanesulfonyl)imide manufactured by Tokyo Chemical Industry Co., Ltd. B1-4 Triethylsulfonium bis(trifluoromethanesulfonyl)imide manufactured by Tokyo Chemical Industry Co., Ltd. B1-5 Trioctylpropylammonium bis(trifluoromethanesulfonyl)imide manufactured by Tokyo Chemical Industry Co., Ltd. B1-6 1-butyl-3-methylpyridinium bis(trifluoromethanesulfonyl)imide manufactured by Tokyo Chemical Industry Co., Ltd. B2-1 Lithium bis(trifluoromethanesulfonyl)imide manufactured by Mitsubishi Materials Electronic Chemicals Co., Ltd. B2-2 Potassium bis(trifluoromethanesulfonyl)imide manufactured by Mitsubishi Materials Electronic Chemicals Co., Ltd.

(26) In Tables 1 and 2, C-1 represents trimethylolpropane xylylene diisocyanate (Takenate D110N manufactured by Mitsui Chemicals, Inc.), C-2 dibenzoyl peroxide, and D-1 -glycidoxypropylmethoxysilane (KBM-403 manufactured by Shin-Etsu Chemical Co., Ltd.).

(27) The results of the examples and Comparative Examples 2 and 5 show that when the onium-anion salt (B1) was used as an ionic compound, good antistatic performance and good durability can be obtained, and the reduction P in polarization degree can be suppressed under humid conditions. Comparisons between Examples 1 to 17 and Comparative Example 2 and between Example 22 and Comparative Example 5 show that when the onium-anion salt (B1) and the alkali metal salt (B2) were used as ionic compounds, as used in the examples, the reduction P in polarization degree can also be suppressed under highly humid conditions. In Comparative Examples 3 and 4 using only the alkali metal salt (B2) as an ionic compound, however, the antistatic performance under highly humid conditions is not sufficient, and the problem of static electricity-induced unevenness is not overcome, although the reduction P in polarization degree is suppressed under highly humid conditions.