Adhesive agent composition, adhesive agent layer, polarizing plate provided with adhesive agent layer, and image formation device

Abstract

A pressure-sensitive adhesive composition, comprising: (A) a (meth)acryl-based polymer; and (B) an ionic compound comprising an anion component and a cation component, wherein the anion component is at least one of an anion component represented by the general formula (1):
(C.sub.nF.sub.2n+1SO.sub.2).sub.2N.sup.,(1)
wherein n is an integer of 3 to 10, and an anion component represented by the general formula (2):
CF.sub.2(C.sub.mF.sub.2mSO.sub.2).sub.2N.sup.,(2)
wherein m is an integer of 2 to 10.

Claims

1. A pressure-sensitive adhesive composition, comprising: (A) a (meth)acryl-based polymer; and (B) an ionic compound comprising an anion component and a lithium cation component, wherein the anion component is at least one of an anion component represented by the general formula (1):
(C.sub.nF.sub.2n+1SO.sub.2).sub.2N.sup.,(1) wherein n is an integer of from 3 to 10, and an anion component represented by the general formula (2):
CF.sub.2(C.sub.mF.sub.2mSO.sub.2).sub.2N.sup.,(2) wherein m is an integer of from 2 to 10.

2. The pressure-sensitive adhesive composition according to claim 1, wherein the anion component of the ionic compound (B) is at least one of a bis(heptafluoropropanesulfonyl)imide anion, a bis(nonafluorobutanesulfonyl)imide anion, and a cyclo-hexafluoropropane-1,3-bis(sulfonyl)imide anion.

3. The pressure-sensitive adhesive composition according to claim 1, which contains from 0.001 to 10 parts by weight of the ionic compound (B) based on 100 parts by weight of the (meth)acryl-based polymer (A).

4. The pressure-sensitive adhesive composition according to claim 1, wherein the (meth)acryl-based polymer (A) contains monomer units derived from an alkyl (meth)acrylate and a carboxyl group-containing monomer.

5. The pressure-sensitive adhesive composition according to claim 1, further comprising (C) a crosslinking agent.

6. The pressure-sensitive adhesive composition according to claim 5, which contains from 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).

7. The pressure-sensitive adhesive composition according to claim 5, wherein the crosslinking agent (C) is at least one of an isocyanate compound and a peroxide.

8. The pressure-sensitive adhesive composition according to claim 1, further comprising from 0.001 to 5 parts by weight of (D) a silane coupling agent based on 100 parts by weight of the (meth)acryl-based polymer (A).

9. The pressure-sensitive adhesive composition according to claim 1, further comprising from 0.001 to 10 parts by weight of (E) a polyether-modified silicone based on 100 parts by weight of the (meth)acryl-based polymer (A).

10. The pressure-sensitive adhesive composition according to claim 1, wherein the (meth)acryl-based polymer (A) has a weight average molecular weight of from 500,000 to 3,000,000.

11. A pressure-sensitive adhesive layer comprising a product made from the pressure-sensitive adhesive composition according to claim 1.

12. A pressure-sensitive adhesive layer-attached polarizing plate comprising at least a polarizing plate and the pressure-sensitive adhesive layer according to claim 11.

13. The pressure-sensitive adhesive layer-attached polarizing plate according to claim 12, further comprising an adhesion-facilitating layer between the polarizing plate and the pressure-sensitive adhesive layer.

14. An image display device comprising at least one piece of the pressure-sensitive adhesive layer-attached polarizing plate according to claim 12.

Description

EXAMPLES

(1) Hereinafter, the present invention will be more specifically described with reference to examples, which, however, are not intended to limit the present invention. In each example, parts and % are all by weight unless otherwise specified.

(2) <Measurement of the Weight Average Molecular Weight of (Meth)Acryl-Based Polymer (A)>

(3) The weight average molecular weight of the (meth)acryl-based polymer (A) was determined using gel permeation chromatography (GPC).

(4) Analyzer: HLC-8120GPC manufactured by TOSOH CORPORATION

(5) Columns: G7000H.sub.XL+GMH.sub.XL+GMH.sub.XL manufactured by TOSOH CORPORATION

(6) Column size: each 7.8 mm30 cm, 90 cm in total

(7) Column temperature: 40 C.

(8) Flow rate: 0.8 ml/minute

(9) Injection volume: 100 l

(10) Eluent: tetrahydrofuran

(11) Detector: differential refractometer (RI)

(12) Standard sample: polystyrene

(13) <Preparation of Polarizing Plate (1)>

(14) 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. Subsequently, the film was 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 20-m-thick polarizer. Saponified triacetylcellulose films each with a thickness of 40 m were bonded to both sides of the polarizer with a polyvinyl alcohol-based adhesive to form a polarizing plate. Hereinafter, this product will be referred to as TAC-based polarizing plate (1).

(15) <Preparation of Polarizing Plate (2)>

(16) A thin polarizing film was prepared as follows. First, a laminate including an amorphous PET substrate and a 9-m-thick PVA layer formed thereon was 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 dyed laminate, and the dyed 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 formed on the amorphous PET substrate, in which the PVA layer contained highly oriented PVA molecules and formed a highly-functional polarizing film in which iodine adsorbed by the dyeing formed a polyiodide ion complex oriented highly in a single direction. A 40-m-thick saponified triacetylcellulose film was bonded to the surface of the polarizing film of the optical film laminate while a polyvinyl alcohol-based adhesive was applied to the surface. Subsequently, after the amorphous PET substrate was peeled off, a 33-m-thick norbornene-based film was bonded to the other surface of the laminate also with a polyvinyl alcohol-based adhesive, so that a polarizing plate having the thin polarizing film was obtained. Hereinafter, this product will be referred to as thin polarizing plate (2).

Production Example 1

Production of Acryl-Based Polymer (A-1)

(17) A reaction vessel equipped with a condenser tube, a nitrogen introducing tube, a thermometer, and a stirrer was charged with 95 parts of butyl acrylate, 5 parts of 4-hydroxybutyl acrylate, and 1 part of AIBN as an initiator (based on 100 parts (solid basis) of the monomers) together with ethyl acetate. The mixture was allowed to react at 60 C. for 7 hours under a nitrogen gas stream. Ethyl acetate was then added to the reaction liquid to form a solution containing an acryl-based polymer (A-1) with a weight average molecular weight of 1,000,000 (solid concentration: 30% by weight).

Production Example 2

Production of Acryl-Based Polymer (A-2)

(18) A solution of an acryl-based polymer (A-2) with a weight average molecular weight of 2,000,000 was prepared as in Production Example 1, except that a monomer mixture containing 95 parts of butyl acrylate and 5 parts of acrylic acid was used instead.

Production Example 3

Production of Acryl-Based Polymer (A-3)

(19) A solution of an acryl-based polymer (A-3) with a weight average molecular weight of 1,800,000 was prepared as in Production Example 1, except that a monomer mixture containing 90 parts of butyl acrylate and 10 parts of acrylic acid was used instead.

Example 1

Preparation of Pressure-Sensitive Adhesive Composition

(20) Based on 100 parts of the solid of the acryl-based polymer (A-1) obtained in Production Example 1, 0.1 part of trimethylolpropane xylylene diisocyanate (Takenate D110N manufactured by Mitsui Chemicals, Inc.), 0.3 part of dibenzoyl peroxide, 0.1 part of -glycidoxypropylmethoxysilane (KBM-403 manufactured by Shin-Etsu Chemical Co., Ltd.), and 0.2 part of lithium cyclo-hexafluoropropane-1,3-bis(sulfonyl)imide (EF-N305 manufactured by Mitsubishi Materials Electronic Chemicals Co., Ltd.) were added to the acryl-based polymer (A-1) solution to form an acryl-based pressure-sensitive adhesive solution.

(21) (Production of Pressure-Sensitive Adhesive Layer-Attached Optical Film)

(22) The acryl-based pressure-sensitive adhesive solution was uniformly applied to the surface of a silicone release agent-treated polyethylene terephthalate film (backing) with a fountain coater and then dried in an air circulation-type thermostatic oven at 155 C. for 2 minutes, so that a 20-m-thick pressure-sensitive adhesive layer was formed on the surface of the backing. Subsequently, the pressure-sensitive adhesive layer-attached separator was bonded to TAC-based polarizing plate (1) to form a pressure-sensitive adhesive layer-attached polarizing plate.

Examples 2 to 18 and Comparative Examples 1 to 6

(23) Pressure-sensitive adhesive layer-attached polarizing plates were prepared as in Example 1, except that the amount of each component used was changed as shown in Table 1 when each pressure-sensitive adhesive composition was prepared, and the type of polarizing plate was changed as shown in Table 1 when each pressure-sensitive adhesive layer-attached polarizing plate was produced.

(24) The pressure-sensitive adhesive layer-attached polarizing plates obtained in the examples and the comparative examples were evaluated as described below. Table 1 shows the evaluation results.

(25) <Surface Resistance (Initial Resistance)>

(26) After the separator film was peeled off from the pressure-sensitive adhesive layer-attached polarizing plate, the surface resistance (/square) of the pressure-sensitive adhesive surface was measured with MCP-HT450 manufactured by Mitsubishi Chemical Analytech Co., Ltd.

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

(28) The prepared pressure-sensitive adhesive layer-attached polarizing plate was cut into a piece with a size of 100 mm100 mm, which was then bonded to a liquid crystal panel. The panel was then 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 generated by an electrostatic generator ESD (ESD-8012A manufactured by Sanki Electronic Industries Co., Ltd.). The time (seconds) required for recovery from the orientation failure-induced display failure was measured with an instantaneous multichannel photodetector system (MCPD-3000 manufactured by Otsuka Electronics Co., Ltd) and evaluated according to the criteria below.

(29) : Display failure disappeared in a time of less than one second.

(30) : Display failure disappeared in a time of one second to less than 10 seconds.

(31) X: Display failure disappeared in a time of 10 seconds or more.

(32) <Surface Resistance (Resistance after Humidity Test)>

(33) The pressure-sensitive adhesive layer-attached polarizing plate obtained in each of the examples and the comparative examples was placed in a thermo-hygrostat at 60 C. and 95% RH. After 48 hours, the pressure-sensitive adhesive layer-attached polarizing plate was taken out and then dried at 60 C. for 2 hours. Subsequently, the separator film was peeled off from the pressure-sensitive adhesive layer-attached polarizing plate, and the surface resistance of the pressure-sensitive adhesive surface was measured with MCP-HT450 manufactured by Mitsubishi Chemical Analytech Co., Ltd.

(34) <Durability>

(35) The separator film was peeled off from the pressure-sensitive adhesive layer-attached polarizing plate obtained in each of the examples and the comparative examples. The polarizing plate was then bonded to a non-alkali glass plate. The resulting laminate was autoclaved at 50 C. and 5 atm for 15 minutes and then stored in a heating oven at 80 C. and stored in a thermo-hygrostat at 60 C. and 90% RH. After 500 hours, the presence or absence of peeling polarizing plate was observed. The case where no peeling was detected at all was rated as , the case where peeling occurred at an invisible level was rated as , the case where visible small peeling occurred was rated as , and the case where significant peeling was observed was rated as X.

(36) <Optical Reliability>

(37) The separator film was peeled off from the pressure-sensitive adhesive layer-attached polarizing plate. The polarizing plate was then bonded to a 0.7-mm-thick non-alkali glass sheet (1737 manufactured by Corning Incorporated) using a laminator. The resulting laminate was then autoclaved at 50 C. and 0.5 MPa for 15 minutes so that the pressure-sensitive adhesive layer-attached polarizing plate was completely bonded to the non-alkali glass sheet. The resulting sample was then stored in a thermo-hygrostat at 60 C. and 95% RH for 500 hours. Before and after the storage, the degree of polarization of the polarizing plate was measured using V7100 manufactured by JASCO Corporation, and the amount (P) of change in the degree of polarization was calculated from the formula: P=(the degree of polarization before the storage)(the degree of polarization after the storage).

(38) TABLE-US-00001 TABLE 1 Pressure-sensitive adhesive composition (Meth)acryl- Ionic Polyether Crosslinking agent (C) Silane based compound compound Isocyanate coupling polymer (B) (E) compound Peroxide agent Type Parts Type Parts Type Parts Type Parts Type Parts Type Parts Example 1 A-1 100 B-1 0.2 C-1 0.1 C-3 0.3 D-1 0.1 Example 2 A-1 100 B-1 1 C-1 0.1 C-3 0.3 D-1 0.1 Example 3 A-1 100 B-2 0.3 C-1 0.1 C-3 0.3 D-1 0.1 Example 4 A-1 100 B-2 2 C-1 0.1 C-3 0.3 D-1 0.1 Example 5 A-1 100 B-3 0.002 C-1 0.1 C-3 0.3 D-1 0.1 Example 6 A-1 100 B-3 0.02 C-1 0.1 C-3 0.3 D-1 0.1 Example 7 A-1 100 B-3 0.4 C-1 0.1 C-3 0.3 D-1 0.1 Example 8 A-1 100 B-3 2 C-1 0.1 C-3 0.3 D-1 0.1 Example 9 A-1 100 B-3 4 C-1 0.1 C-3 0.3 D-1 0.1 Example 10 A-1 100 B-3 10 C-1 0.1 C-3 0.3 D-1 0.1 Example 11 A-1 100 B-3 2 E-1 0.5 C-1 0.1 C-3 0.3 D-1 0.1 Example 12 A-1 100 B-3 2 E-2 0.5 C-1 0.1 C-3 0.3 D-1 0.1 Example 13 A-1 100 B-3 2 C-1 0.2 D-1 0.1 Example 14 A-1 100 B-3 2 C-1 0.1 C-3 0.3 D-1 0.1 Example 15 A-2 100 B-3 2 C-2 0.4 C-3 0.3 D-1 0.1 Example 16 A-3 100 B-3 2 C-2 0.4 C-3 0.3 D-1 0.1 Example 17 A-1 100 B-4 2 C-1 0.1 C-3 0.3 D-1 0.1 Example 18 A-1 100 B-4 2 C-1 0.1 C-3 0.3 D-1 0.1 Comparative Example 1 A-1 100 0 C-1 0.1 C-3 0.3 D-1 0.1 Comparative Example 2 A-1 100 B-5 0.7 C-1 0.1 C-3 0.3 D-1 0.1 Comparative Example 3 A-1 100 B-5 3.5 C-1 0.1 C-3 0.3 D-1 0.1 Comparative Example 4 A-1 100 B-5 3.5 E-1 0.5 C-1 0.1 C-3 0.3 D-1 0.1 Comparative Example 5 A-1 100 B-6 3.5 C-1 0.1 C-3 0.3 D-1 0.1 Comparative Example 6 A-1 100 B-7 3.5 C-1 0.1 C-3 0.3 D-1 0.1 Evaluations Surface resistance after Initial surface humidification resistance (60 C./95% RH for 50 h) Static Static electricity- electricity- Optical induced induced Durability reliability Polarizing plate type / unevenness / unevenness Heating Humidification Example 1 TAC-based polarizing plate (1) 1.60E+12 2.50E+12 0.1 Example 2 TAC-based polarizing plate (1) 1.34E+11 3.48E+12 0.1 Example 3 TAC-based polarizing plate (1) 4.70E+11 1.06E+12 0.2 Example 4 TAC-based polarizing plate (1) 6.77E+10 2.77E+11 0.1 Example 5 TAC-based polarizing plate (1) 8.10E+12 8.51E+12 0.2 Example 6 TAC-based polarizing plate (1) 3.20E+12 4.80E+12 0.1 Example 7 TAC-based polarizing plate (1) 5.22E+11 8.19E+11 0.2 Example 8 TAC-based polarizing plate (1) 9.89E+10 2.22E+11 0.1 Example 9 TAC-based polarizing plate (1) 5.00E+10 9.52E+10 0.1 Example 10 TAC-based polarizing plate (1) 2.30E+10 3.40E+10 0.1 Example 11 TAC-based polarizing plate (1) 1.10E+11 2.52E+11 0.2 Example 12 TAC-based polarizing plate (1) 9.01E+10 9.52E+10 0.1 Example 13 TAC-based polarizing plate (1) 1.01E+11 2.22E+11 0.1 Example 14 Thin polarizing plate (2) 9.90E+10 2.22E+11 0.2 Example 15 TAC-based polarizing plate (1) 2.0E+12 3.10E+12 0.1 Example 16 TAC-based polarizing plate (1) 5.10E+12 7.70E+12 0.2 Example 17 TAC-based polarizing plate (1) 1.27E+11 7.71E+11 0.1 Example 18 Thin polarizing plate (2) 1.20E+11 7.52E+11 1.2 Comparative TAC-based polarizing plate (1) 10.sup.13 or more X 10.sup.13 or more X 0.1 Example 1 Comparative TAC-based polarizing plate (1) 4.36E+11 10.sup.13 or more X 0.1 Example 2 Comparative TAC-based polarizing plate (1) 7.06E+10 10.sup.13 or more X 0.1 Example 3 Comparative TAC-based polarizing plate (1) 6.89E+10 10.sup.13 or more X 0.2 Example 4 Comparative TAC-based polarizing plate (1) 5.85E+10 10.sup.13 or more X 0.2 Example 5 Comparative TAC-based polarizing plate (1) 6.65E+10 10.sup.13 or more X 0.2 Example 6

(39) Concerning the ionic compound (B) shown in Table 1, B-1 represents lithium cyclo-hexafluoropropane-1,3-bis(sulfonyl)imide (EF-N305 (trade name) manufactured by Mitsubishi Materials Electronic Chemicals Co., Ltd.), B-2 lithium bis(heptafluoropropanesulfonyl)imide (manufactured by Wako Pure Chemical Industries, Ltd.), B-3 lithium bis(nonafluorobutanesulfonyl)imide (EF-N445 (trade name) manufactured by Mitsubishi Materials Electronic Chemicals Co., Ltd.), B-4 1-butyl-3-methylpyridium bis(nonafluorobutanesulfonyl)imide (BuMePy.N441 (trade name) manufactured by Mitsubishi Materials Electronic Chemicals Co., Ltd.), B-5 lithium bis(trifluoromethanesulfonyl)imide (manufactured by Wako Pure Chemical Industries, Ltd.), B-6 1-butyl-3-methylpyridium bis(trifluoromethanesulfonyl)imide (CIL-312 (trade name) manufactured by Japan Carlit Co., Ltd.), and B-7 lithium bis(pentafluoroethanesulfonyl)imide (manufactured by Wako Pure Chemical Industries, Ltd.).

(40) Concerning the crosslinking agent (C), C-1 represents an isocyanate crosslinking agent manufactured by Mitsui Chemicals, Inc. (Takenate D110N (trade name), trimethylolpropane xylylene diisocyanate), C-2 CORONATE L (trade name) manufactured by Nippon Polyurethane Industry Co., Ltd, and C-3 benzoyl peroxide (NYPERBMT) manufactured by NOF CORPORATION.

(41) Concerning the silane coupling agent (D), D-1 represents KBM-403 manufactured by Shin-Etsu Chemical Co., Ltd.

(42) Concerning the polyether compound (E), E-1 represents SILYL SAT10 (trade name) manufactured by Kaneka Corporation, and E-2 SIB1824.82 (trade name) manufactured by Gelest, Inc.