Adhesive film for polarizing plate, polarizing plate comprising the same and optical display apparatus comprising the same

Patent metadata

Field	Value
Publication number	US-2022049136-A1
Application number	US-202117376881-A
Country	US
Kind code	A1
Filing date	Jul 15, 2021
Priority date	Aug 11, 2020
Publication date	Feb 17, 2022
Grant date	—

Abstract

An adhesive film for polarizing plates, a polarizing plate including the same, and an optical display apparatus including the same are provided. An adhesive film for polarizing plates is formed of an adhesive composition including a (meth)acrylic copolymer, an isocyanate curing agent, a metal chelate curing agent, and an antistatic agent, and has a surface resistance difference ΔSR of 1.0 (log(Ω/□)) or less, as calculated by Equation 1 and, in Equation 1, SR1 is 10 (log(Ω/□)) or less.

First claim

What is claimed is:

1 . An adhesive film for polarizing plates formed of an adhesive composition comprising a (meth)acrylic copolymer, an isocyanate curing agent, a metal chelate curing agent, and an antistatic agent,
the adhesive film having a surface resistance difference ΔSR of about 1.0 (log(Ω/□)) or less, as calculated by the following Equation 1:
Δ SR=SR 2− SR 1,

where SR1 is a log value (unit: log(Ω/□)) of initial surface resistance of the adhesive film, and SR2 is a log value (unit: log(Ω/□)) of surface resistance of the adhesive film as measured after the adhesive film is left at 85° C. and 85% RH for 250 hours, and in Equation 1, SR1 is about 10(log(Ω/□)) or less.

2 . The adhesive film for polarizing plates according to claim 1 , wherein the adhesive film has a surface resistance of about 1×10 8 Ω/□ to about 1×10 11 Ω/□, as measured after the adhesive film is left at 85° C. and 85% RH for 250 hours.

3 . The adhesive film for polarizing plates according to claim 1 , wherein the adhesive film has a peel strength difference of about 2.0 N/25 mm or less between initial peel strength at 25° C. and peel strength at 85° C. after the adhesive film is left at 85° C. for 5 min.

4 . The adhesive film for polarizing plates according to claim 1 , wherein the adhesive film has a peel strength difference of about 1.0 N/25 mm or more between initial peel strength at 25° C. and peel strength at 85° C. after the adhesive film is left at 85° C. for 5 min.

5 . The adhesive film for polarizing plates according to claim 1 , wherein the adhesive film has a modulus of about 40 kPa or more at 85° C.

6 . The adhesive film for polarizing plates according to claim 1 , wherein the adhesive composition has a gel fraction difference of about 5% or less between a gel fraction after aging for 4 days and a gel fraction after aging for 7 days, as calculated by the following Equation 2:
Gel fraction=( WC−WA )/( WB−WA )×100,
where WA is the weight of a wire mesh, WB is the total weight of the wire mesh and a specimen wrapped by the wire mesh so as not to leak therefrom, in which the specimen having the adhesive film stacked on a release film is obtained by coating 1.0 g of the adhesive composition to a thickness of 15 μm on the release film, followed by aging the adhesive composition on the release film at 35° C. and 45% RH for 4 days or 7 days, and WC is the total weight of the wire mesh and the adhesive film, in which the adhesive film wrapped by the wire mesh is completely dipped in a sample bottle containing 50 cc ethyl acetate, left for 1 day, and dried at 100° C. for 12 hours.

7 . The adhesive film for polarizing plates according to claim 1 , wherein the (meth)acrylic copolymer is free from a carboxylic acid group.

8 . The adhesive film for polarizing plates according to claim 1 , wherein the (meth)acrylic copolymer comprises a (meth)acrylic copolymer of a monomer mixture comprising a (meth)acrylic monomer having a glass transition temperature (Tg) of about 0° C. or more in a homopolymer phase, an alkyl group-containing (meth)acrylic monomer, and a crosslinking functional group-containing (meth)acrylic monomer.

9 . The adhesive film for polarizing plates according to claim 8 , wherein the (meth)acrylic monomer having the glass transition temperature (Tg) of about 0° C. or more in the homopolymer phase comprises at least one selected from among methyl acrylate, methyl methacrylate, t-butyl acrylate, t-butyl methacrylate, isobornyl acrylate, isobornyl methacrylate, and acryloyl morpholine.

10 . The adhesive film for polarizing plates according to claim 8 , wherein the monomer mixture comprises about 1 wt % to about 40 wt % of the (meth)acrylic monomer having the glass transition temperature (Tg) of about 0° C. or more in the homopolymer phase, about 40 wt % to about 95 wt % of the alkyl group-containing (meth)acrylic monomer, and about 0.01 wt % to about 20 wt % of the crosslinking functional group-containing (meth)acrylic monomer.

11 . The adhesive film for polarizing plates according to claim 8 , wherein the monomer mixture comprises an aromatic group-containing (meth)acrylic monomer.

12 . The adhesive film for polarizing plates according to claim 11 , wherein the aromatic group-containing (meth)acrylic monomer has a glass transition temperature of less than about 5° C. in a homopolymer phase and is present in an amount of about 1 wt % to about 35 wt % in the monomer mixture.

13 . The adhesive film for polarizing plates according to claim 1 , wherein the isocyanate curing agent has an isocyanurate group.

14 . The adhesive film for polarizing plates according to claim 1 , wherein the antistatic agent is present in an amount of about 5 parts by weight to about 30 parts by weight relative to 100 parts by weight of the (meth)acrylic copolymer.

15 . The adhesive film for polarizing plates according to claim 1 , wherein the antistatic agent comprises at least one selected from among a surfactant, an ionic liquid, an alkali metal salt, a metal oxide, fine metal particles, a conductive polymer, carbon, and carbon nanotubes.

16 . The adhesive film for polarizing plates according to claim 1 , wherein the adhesive film comprises about 0.01 parts by weight to about 5 parts by weight of the isocyanate curing agent, about 0.01 parts by weight to about 5 parts by weight of the metal chelate curing agent, and about 5 parts by weight to about 30 parts by weight of the antistatic agent relative to 100 parts by weight of the (meth)acrylic copolymer.

17 . A polarizing plate comprising: a polarizer and the adhesive film for polarizing plates according to claim 1 stacked on a surface of the polarizer.

18 . An optical display apparatus comprising the polarizing plate according to claim 17 .

Assignees

• Samsung Sdi Co Ltd

Inventors

• Lee Seung Jun
• Kim Dae Yun
• Kim Il Jin
• Yu Mi Yeon
• Jeong Woo Jin
• Cho Ha Yun

Classifications

• C09J133/10 Primary

  Homopolymers or copolymers of methacrylic acid esters · CPC title

• C09J133/08 Primary

  Homopolymers or copolymers of acrylic acid esters · CPC title

• G02B5/3025

  Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state (G02B5/3008, G02B5/3016 take precedence) · CPC title

• G02B5/3016

  involving passive liquid crystal elements (optical properties of liquid crystals G02F1/0063; polarising elements associated with active liquid crystal devices G02F1/133528) · CPC title

• C09J7/10

  without carriers · CPC title