JP3012860B2 - Polarizer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polarizing plate.

[0002]

2. Description of the Related Art A polarizing plate is mounted on a liquid crystal display device and widely used. A protective film is laminated on both surfaces of a polarizing film, and an adhesive is provided on an upper surface of at least one of the protective films. One in which a layer is formed and a separate film is adhered through an adhesive layer is used. However, such a polarizing plate is
When the separation film is peeled off and mounted on a liquid crystal display device, static electricity is generated, and therefore, development of a countermeasure for this is strongly desired.

[0003] By adhering a separate film using a pressure-sensitive adhesive mixed with a surfactant, the surfactant transferred to the surface of the pressure-sensitive adhesive layer adsorbs moisture in the air to exhibit an antistatic function. (Japanese Patent Application Laid-Open No. 61-138901), however, has a drawback that the antistatic performance and the adhesive strength greatly depend on humidity.

[Means for Solving the Problems]

The inventors of the present invention have made intensive studies to solve such problems, and as a result, have found that such problems can be solved by using a specific pressure-sensitive adhesive, and have reached the present invention.

That is, the present invention relates to a polarizing plate having a protective film laminated on the surface of a polarizing film and an adhesive layer provided on the surface of the protective film, wherein an electrolyte salt and an organopolysiloxane represented by the following formula are used as the adhesive. 0.1 / 100 ≦ (weight of A) / (weight of B) ≦ 2.0, which is composed of the ionic conductive composition (A) composed of siloxane and the acrylic copolymer (B).
/ 100 The polarizing plate characterized by using an adhesive Wherein R ¹ is a monovalent organic group, R ^{2 to} R ⁴ are alkylene groups, R
⁵ represents hydrogen or a monovalent organic group. -M is an integer of 0-100, n is an integer of 1-100.・-(-Si (R ¹ R ¹ ) O-)-unit and-(-Si (R ¹ R
² ) The arrangement order of O-)-units is arbitrary. A and b are each an integer of 0 to 100, and are not 0 at the same time. ^{· - (- R 3 O -} ) - and ^{- (- R 4 O -)} - order of arrangement is arbitrary. It is about.

Hereinafter, the present invention will be described in detail. As the organopolysiloxane, those represented by the following general formula are used. In the formula, R ¹ is a monovalent organic group, R ^{2 to} R ⁴ are an alkylene group, R ⁵ is hydrogen or a monovalent organic group, and m is 0 to 10
An integer of 0 and n is an integer of 1 to 100. Are arbitrary, and a and b are each 0 to 1
00 and not 0 at the same time,-(-R
³ O -) - and ^{- (- R 4 O -)} - order of arrangement is arbitrary.

Examples of R ¹ include a methyl group, an ethyl group,
An alkyl group having 1 to 4 carbon atoms such as propyl group; an aryl group having 6 to 8 carbon atoms such as phenyl group and tolyl group; an aralkyl group having 7 to 9 carbon atoms such as benzyl group and phenethyl group; May have a substituent. R ² , R ³
And examples of R ⁴ include methylene group, ethylene group, and an alkylene group having 1 to 8 carbon atoms such as propylene group, also R ^2, R ³ and R ⁴ are the same, or different, One of R ³ and R ⁴ is preferably an ethylene group or a propylene group in order to increase the concentration of the electrolyte salt dissolved in the polyoxyalkylene side chain. Examples of R ⁵ include an alkyl group having 1 to 5 carbon atoms such as a methyl group, an ethyl group, and a propyl group; an acyl group having 2 to 6 carbon atoms such as an acetyl group and a propynyl group; and a substituent such as a hydroxyl group. May be provided. Such an organopolysiloxane can be obtained by, for example, grafting an organic compound having an unsaturated bond and a polyoxyalkylene group to an organopolysiloxane main chain having silicon hydride by a hydrosilylation reaction.

Examples of the electrolyte salt include electrolyte salts in which the cation is a cation of a metal belonging to Group I or Group II of the periodic table. Examples of the cation include lithium, sodium, potassium, magnesium, calcium, and the like. Cations such as barium are exemplified.

Specific examples of the electrolyte salt include lithium iodide, lithium perchlorate, lithium thiocyanate, lithium borofluoride, lithium tetrafluoromethanesulfonate, sodium iodide, sodium perchlorate, and barium iodide. Salts or hydrated salts can be used, and they can be used alone or as a mixture.

In the ionic conductive composition (A), the total number of moles of the oxyalkylene group [RO], that is, R
The ratio of the number of moles of cation [M ⁺ ] to the total number of moles of ³ O and R ⁴ O ([M ⁺ ] / [RO]) is 0.00.
The range of 5 to 1.5 is preferable in terms of antistatic effect and transparency, and the range of 0.01 to 0.5 is particularly preferable.

As the acrylic copolymer (B), those commonly used can be used. For example, an alkyl ester of acrylic acid or methacrylic acid having an alkyl group having 1 to 11 carbon atoms is mainly used. As a component, there may be mentioned those obtained by copolymerizing a polar monomer which can be copolymerized with the component and further crosslinking by using a crosslinking agent. Examples of the alkyl ester of acrylic acid or methacrylic acid include ethyl methacrylate, 2-ethylhexyl methacrylate, and n-acrylic acid.
Butyl and the like and polar monomers include acrylic acid, methacrylic acid, 2-hydroxyethyl acrylate, 2-hydroxymethyl methacrylate and the like. Examples of the crosslinking agent include aliphatic di- or triisocyanate, aromatic di- or triisocyanate, and tolylene diisocyanate, hexamethylene diisocyanate, and trimethylolpropane tolylene diisocyanate. And trimethylolpropane hexamethylene diisocyanate.

The weight ratio of the ionic conductive composition (A) to the acrylic copolymer (B) is 0.1% to 2.0%. If it is less than 0.1%, the antistatic effect is not sufficient, and if it exceeds 2.0%, the balance of the performance of the polarizing plate,
For example, the balance between durability and antistatic properties is lost. The thickness of the pressure-sensitive adhesive layer provided on at least one of the protective films is, for example, about 5 to 50 μm, and preferably about 15 to 25 μm in consideration of adhesive performance.

The types of the polarizing film, the protective film and the separate film are not limited at all, and a film made of a commonly used thermoplastic resin can be used. For example, the polarizing film may be polyvinyl alcohol. A film composed of a hydrophilic polymer imparted with polarizability by adsorbing and orienting iodine and / or a dichroic dye typified by a polyester-based polarizing film, a polyene-based film having a polyene orientation, and laminated on both surfaces of a polarizing film Examples of the protective film include a film made of a transparent thermoplastic resin such as a triacetyl cellulose film, a polycarbonate film, and an acrylic film. Examples of the separate film include a polyester film, an ethylene-vinyl acetate copolymer film, and a polyethylene film. Film made of thermoplastic resin It can gel. The thickness of the film is not particularly limited, and is, for example, about 10 μm to 30 μm as a polarizing film, about 50 μm to 200 μm as a protective film, and about 5 μm to 50 μm as a separate film.

[0014]

The polarizing plate of the present invention is excellent in antistatic properties, adhesiveness and durability, does not have a problem as when a surfactant is mixed, and can be used stably.

[0015]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples. The adhesive strength, antistatic property and durability were evaluated by the following methods.

<Adhesive force> thickness 180 μm, width 500 m
m, polarizing plate with a length of 1000 mm (Structure: protective film /
Polarizing film / protective film. The protective film and the polarizing film are a triacetyl cellulose film (thickness: 80 μm) and a polyvinyl alcohol-based film (thickness: 25 μm), respectively. ) Is coated on one side with an adhesive so as to have a thickness of 25 μm after drying, and a 25 μm thick PET film is laminated as a release film on the adhesive side, and is placed at 23 ° C. × 50% RH for one week. Aged. Width 2
5 mm, a 250 mm long test piece was cut out, the PET film was peeled off, and the surface of the adhesive was adhered using a laminator to a glass plate treated by ultrasonic cleaning in water containing a neutral detergent so that air did not enter. It was left at 23 ° C. × 50% RH for 2 hours. Next, after autoclaving at 50 ° C. × 5 kg / cm ² × 20 minutes, aging was performed at 23 ° C. × 50% RH for 24 hours. Thereafter, the polarizing plate was peeled off from the glass plate using a universal tensile tester, and the 180-degree peel strength was measured (speed 300 mm / min.).

<Durability> 23 prepared in the above adhesive strength test
A test piece having a width of 80 mm and a length of 150 mm was cut out from the polarizing plate that had been aged at a temperature of 50 ° C. × 50% for one week, attached to a glass plate in the same manner as in the adhesion test, and subjected to autoclaving. About 0% humidity and 80 ° C in advance
And an oven adjusted to a humidity of 90% RH and a temperature of 60 ° C., and after one day, 14
The state of the polarizing plate after one day was visually judged. A: No foaming, peeling, discoloration, etc. B: There is no peeling or discoloration, but slight foaming is observed. C: There is no peeling or discoloration, but considerable foaming is observed. D: No discoloration, but many foaming and peeling are observed.

<Antistatic Property> 23 prepared by adhesion test
A test piece having a width of 150 mm and a length of 200 mm was cut out from the polarizing plate after aging at a temperature of 50 ° C. × 50% RH for one week. PE
With the corners of the T film, diagonally move the PET film to the center, ie, halve the PET film
It peeled off for 2 seconds, immediately brought the pressure-sensitive adhesive layer surface closer to the dried tobacco ash (distance: about 1 cm), and observed the degree of adhesion of the ash with the naked eye. A: No ash adhesion. B: Ash adheres very slightly. C: Ash adheres to the entire surface.

<Production Example 1: Ion conductive composition> 100 parts of compound (1) and 650 parts of compound (2) are dissolved in 3000 parts of tetrahydrofuran, and reacted at 50 ° C for 16 hours using chloroplatinic acid as a catalyst. (3) was obtained. 10 parts of lithium perchlorate was mixed and dispersed in 90 parts of the obtained compound (3) to obtain an ion conductive composition ([M ⁺ ] / [RO] = 0.07).

<Production Example 2: Ion-conductive composition> 100 parts of compound (4) and 132 parts of compound (5) were dissolved in 928 parts of tetrahydrofuran, and chloroplatinic acid was used as a catalyst.
The reaction was carried out at 50 ° C. for 8 hours to obtain a compound (6). 10 parts of lithium perchlorate was mixed and dispersed in 90 parts of the obtained compound (6) to obtain an ion conductive composition ([M ⁺ ] / [RO] = 0.10).

<Production Example 3: Ion conductive composition> 100 parts of compound (4) and compound (7) 2 used in Production Example 2
60 parts was dissolved in 1440 parts of tetrahydrofuran, and reacted at 50 ° C. for 16 hours using chloroplatinic acid as a catalyst to obtain a compound (8). 10 parts of lithium perchlorate was mixed and dispersed in 90 parts of the obtained compound (8) to obtain an ion conductive composition ([M ⁺ ] / [RO] = 0.08).

<Production Example 4: Ion conductive composition> 20 parts of lithium perchlorate was mixed and dispersed in 80 parts of the compound (6) obtained in Production Example 2 to obtain an ionic conductive composition ( [M ⁺ ] / [RO] = 0.22).

<Production Example 5: Ion conductive composition> 40 parts of lithium perchlorate was mixed and dispersed in 60 parts of the compound (8) obtained in Production Example 3 to obtain an ion conductive composition ( [M ⁺ ] / [RO] = 0.49).

<Synthesis of Acrylic Copolymer (B)> The following components were charged into a polymerization reactor equipped with a stirrer, a cooler, a thermometer, and a nitrogen introduction device, and oxygen in the polymerization reactor was supplied with a nitrogen stream. , And the temperature was raised to 55 ° C. Butyl acrylate 870 g Ethyl acrylate 100 g 2-hydroxyethyl methacrylate 10 g Acrylic acid 20 g Azoisobutyronitrile 0.4 g Ethyl acetate 1000 g After reacting for 4 hours while maintaining at 55 ° C., 500 g of ethyl acetate
Was added, and after 3 hours, 500 g of ethyl acetate was added. After 3 hours, 1000 g of ethyl acetate and 3 g of azoisobutyronitrile were added, and the temperature was raised to 70 ° C. to carry out a polymerization reaction for 4 hours. The polymerization solution was filtered through a glass filter to obtain an ethyl acetate solution containing 25% of the acrylic copolymer (B).

<Examples and Comparative Examples> Using the ionic conductive compositions (A) obtained in Production Examples 1 to 5, a surfactant (C) and an acrylic copolymer (B) shown below, The adhesive strength, durability and antistatic properties were evaluated using the compositions shown in Tables 1 to 3. At this time, a small amount of trimethylol tolylene diisocyanate was added to the acrylic copolymer (B). Symbol Type of surfactant a: lauryl dimethyl ammonium ethosulfate (cationic) b: sodium dodecylbenzenesulfonate (anionic) c: glycerin monostearate (nonionic) d: stearyldiethanolamine (nonionic) Table 1 3 are shown.

<Table 1> Example No. of Composition A Durable Antistatic Property A / B adhesive strength DRY WET 1 0.1 1000 A / A A / AB 2 2.0 850 A / B A / A A 3 0.5 1050 A / A A / A B 4 1.0 900 A / B A / A A 5 0.5 950 A / A A / A B 6 2.0 860 A / B A / A A 70.5 980 A / A A / A A 8 1.0 930 A / B A A / A 90.5 900 A / A A / A A 101.0870 A / B A / A A where: A / B: when the weight of the acrylic copolymer (B) is 100, Shows the weight of component A.・ Adhesive strength: unit g / 25mm ・ Durability: “DRY” is 80 ° C. × about 0% RH, “WE
“T” indicates 60 ° C. × 90% RH. A / B indicates that the state after one day was A and the state after 14 days was B. (The same applies to Tables 2 and 3.)

[0027] No. of <Table 2> Comparative Composition A durable antistatic property Example A / B adhesive strength DRY WET 1 -1250 A / A A / AC 2 0.05 1200 A / A A / AC 3 2.5 600 C / DC / DA 40.05 1180 A / A A / A C 52.5 550 C / D C / D A 6 0.05 1200 A / A A / A C 72.5 540 C / D C / D A 82.5 570 C / D C / D A 9 0.05 1150 A / A A / A C 10 2.5 570 C / D C / D A

<Table 3> Comparative Activator C No. of Durability Antistatic Example 1. C / B adhesive strength DRY WET 11a 0.05 1200 A / A A / AC 12a 2.5 600 C / DC C / DA 13b 0.05 1180 A / A A / A C 14 b 5 550 C / DC / DA 15c 0.05 1160 A / AA / AC 16c 2.5 540 C / DC / DA 17d 0.05 1150 A / AA / AC 18d 2.5 570 C / D C / DA

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Akira Matsumoto 17-23 Sugai Kitano-do, Seika-cho, Soraku-gun, Kyoto (72) Inventor Hisao Shimanoe 1-2-703, Harayamadai, Sakai-shi, Osaka ( 56) References JP-A-61-138901 (JP, A) JP-A-2-193998 (JP, A) JP-A-5-78543 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , (DB name) G02B 5/30

Claims (2)

(57) [Claims] 1. A polarizing plate having a protective film laminated on a surface of a polarizing film and an adhesive layer provided on the surface of the protective film, wherein the adhesive comprises an electrolyte salt and an ion comprising an organopolysiloxane represented by the following formula. Consisting of a conductive composition (A) and an acrylic copolymer (B), 0.1 / 100 ≦ (weight of A) / (weight of B) ≦ 2.0
A polarizing plate, characterized by using a pressure-sensitive adhesive of (/ 100). Wherein R ¹ is a monovalent organic group, R ^{2 to} R ⁴ are alkylene groups, R
⁵ represents hydrogen or a monovalent organic group. -M is an integer of 0-100, n is an integer of 1-100.・-(-Si (R ¹ R ¹ ) O-)-unit and-(-Si (R ¹ R
² ) The arrangement order of O-)-units is arbitrary. A and b are each an integer of 0 to 100, and are not 0 at the same time. ^{· - (- R 3 O -} ) - and ^{- (- R 4 O -)} - order of arrangement is arbitrary. 2. The ratio of the number of moles of metal cations in the electrolyte salt [M ⁺ ] to the number of moles of oxyalkylene groups [RO] in the ion conductive composition (A) ([M ⁺ ] / [RO] ) Is 0.005 to 1.5.