Adhesive composition for optical member, optical member comprising same, and optical display device comprising same

1. An adhesive composition for optical members, comprising:

a (meth)acrylic copolymer comprising both an acetoacetoxy group and a hydroxyl group;

a metal chelate curing agent; and

a tri- or higher functional isocyanate curing agent,

wherein the (meth)acrylic copolymer has an acid value of 0 mg KOH/g, and

the tri- or higher functional isocyanate curing agent is greater than or equal to the metal chelate curing agent in amount.

2. The adhesive composition for optical members according to claim 1 , wherein the (meth)acrylic copolymer containing the acetoacetoxy group is a copolymer of a monomer mixture comprising about 1 wt % or more of an acetoacetoxy group-containing monomer in the monomer mixture.

3. The adhesive composition for optical members according to claim 2 , wherein the acetoacetoxy group-containing monomer is present in an amount of about 1 wt % to about 10 wt % in the monomer mixture.

4. The adhesive composition for optical members according to claim 2 , wherein the monomer mixture comprises the acetoacetoxy group-containing monomer, an alkyl group-containing (meth)acrylic monomer, and a hydroxyl group-containing (meth)acrylic monomer.

5. The adhesive composition for optical members according to claim 1 , wherein the metal chelate curing agent comprises an acetylacetonate group.

6. The adhesive composition for optical members according to claim 1 , wherein the metal chelate curing agent is present in an amount of about 0.01 parts by weight to about 1 part by weight relative to 100 parts by weight of the (meth)acrylic copolymer.

7. The adhesive composition for optical members according to claim 1 , wherein the tri- or higher functional isocyanate curing agent comprises at least one of a trifunctional trimethylolpropane-modified toluene diisocyanate adduct, a trifunctional toluene diisocyanate trimer, a trimethylolpropane-modified xylene diisocyanate adduct, a hexafunctional trimethylolpropane-modified toluene diisocyanate, and a hexafunctional isocyanurate-modified toluene diisocyanate.

8. The adhesive composition for optical members according to claim 1 , wherein the tri- or higher functional isocyanate curing agent comprises a trifunctional isocyanate curing agent having an isocyanurate group.

9. The adhesive composition for optical members according to claim 1 , wherein the tri- or higher functional isocyanate curing agent is present in an amount of about 0.01 parts by weight to about 5 parts by weight relative to 100 parts by weight of the (meth)acrylic copolymer.

10. The adhesive composition for optical members according to claim 1 , further comprising: a silane coupling agent.

11. An adhesive composition for optical members, comprising:

a (meth)acrylic copolymer comprising both an acetoacetoxy group and a hydroxyl group;

a metal chelate curing agent; and

a tri- or higher functional isocyanate curing agent,

wherein a gel fraction difference is about 5% or less, as calculated by the following Equation 1, and the (meth)acrylic copolymer has an acid value of 0 mg KOH/g:

Gel fraction difference=GF7−GF1,  <Equation 1>

where GF7 is a gel fraction after aging for 7 days as calculated by the following Equation 2, and GF1 is a gel fraction after aging for 1 day as calculated by the following Equation 2:

Gel fraction=(( WC−WA )/( WB−WA ))×100,  <Equation 2>

where WA is a weight of a wire mesh,

WB is a total weight of the wire mesh and a specimen of an adhesive film placed on the wire mesh, in which the specimen is obtained by depositing 1.0 g of the adhesive composition to a thickness of 20 μm on a release film, followed by aging at 35° C. and 45% RH (relative humidity) for 1 day or for 7 days, respectively, and

WC is a total weight of the wire mesh and the adhesive film, which have been placed in a sample bottle, left for 1 day after adding 50 cc of ethyl acetate thereto, and then dried at 100° C. for 12 hours.

12. The adhesive composition for optical members according to claim 11 , wherein the adhesive film formed of the adhesive composition has an index of adhesion of about 3 to about 15, as calculated by Equation 3:

Index of adhesion=substrate adhesive strength/peel strength,  <Equation 3>

where substrate adhesive strength is 180° peel strength between the adhesive film and a polarizing plate in accordance with ASTM D3330, and peel strength is 180° peel strength between the adhesive film and a glass plate in accordance with ASTM D3330.

13. The adhesive composition for optical members according to claim 11 , wherein the (meth)acrylic copolymer is a copolymer of a monomer mixture comprising about 1 wt % to about 10 wt % of an acetoacetoxy group-containing monomer in the monomer mixture.

14. The adhesive composition for optical members according to claim 11 , wherein the (meth)acrylic copolymer comprises a copolymer of a monomer mixture comprising an acetoacetoxy group-containing monomer, an alkyl group-containing (meth)acrylic monomer, and a hydroxyl group-containing (meth)acrylic monomer.

15. The adhesive composition for optical members according to claim 11 , wherein the tri- or higher functional isocyanate curing agent comprises at least one of a trifunctional trimethylolpropane-modified toluene diisocyanate adduct, a trifunctional toluene diisocyanate trimer, a trimethylolpropane-modified xylene diisocyanate adduct, a hexafunctional trimethylolpropane-modified toluene diisocyanate, and a hexafunctional isocyanurate-modified toluene diisocyanate.

16. An optical member comprising an adhesive film formed of the adhesive composition for optical members according to claim 1 .

17. The optical member according to claim 16 , wherein the optical member comprises a polarizing plate.

18. An optical display device comprising the optical member according to claim 16 .