Porous adhesive film, optical member comprising same, and optical display device comprising same
The present invention provides: a porous adhesive film which is formed from an adhesive composition including (meth)acrylic copolymers having hydroxyl groups and alkylene glycol groups, and which has a modulus of less than approximately 30 kPa at 25° C. and a peel strength of approximately 700 gf/in or greater at 25° C.; an optical member comprising same; and an optical display device comprising same.
1. A porous adhesive film formed of an adhesive composition comprising a (meth)acrylic copolymer having a hydroxyl group and an alkylene glycol group,
wherein the porous adhesive film has a modulus of less than about 30 kPa at 25° C. and a modulus ratio between modulus at 25° C. and modulus at 80° C. of about 1:0.7 to about 1:1.0,
the porous adhesive film has a peel strength of about 700 gf/in or more at 25° C. and
the porous adhesive film includes bubbles distributed over the porous adhesive film and occupying a volume of 28 vol % to about 50 vol % relative to a total volume of the porous adhesive film,
wherein the (meth)acrylic copolymer comprises a copolymer of a monomer mixture comprising a hydroxyl group-containing (meth)acrylate, an alkylene glycol group-containing (meth)acrylate, and an alkyl group-containing (meth)acrylate,
wherein the alkylene glycol group-containing (meth)acrylate comprises polyethylene glycol (meth)acrylate, and
wherein the polyethylene glycol (meth)acrylate comprises at least one selected from among ethyl hexyl polyethylene glycol (meth)acrylate, and octyl polyethylene glycol (meth)acrylate.
2. The porous adhesive film according to claim 1 , wherein the porous adhesive film has a monolayer structure.
3. The porous adhesive film according to claim 1 , wherein the volume occupied by the bubbles of the porous adhesive film is 30 vol % to about 50 vol % relative to the total volume of the porous adhesive film.
4. The porous adhesive film according to claim 1 , wherein the monomer mixture comprises about 0.01 wt % to about 20 wt % of the alkylene glycol group-containing (meth)acrylate.
5. The porous adhesive film according to claim 1 , wherein the monomer mixture comprises about 5 wt % to about 40 wt % of the hydroxyl group-containing (meth)acrylate, about 0.01 wt % to about 20 wt % of the alkylene glycol group-containing (meth)acrylate, and about 50 wt % to about 80 wt % of the alkyl group-containing (meth)acrylate.
6. The porous adhesive film according to claim 1 , wherein the adhesive composition further comprises an alkylene glycol group-containing crosslinking agent.
7. The porous adhesive film according to claim 1 , wherein the porous adhesive film has a modulus of about 50 kPa or less at 80° C.
8. The porous adhesive film according to claim 1 , wherein the porous adhesive film has a thickness of about 10 μm to about 300 μm.
9. An optical member comprising: an optical film; and the porous adhesive film according to claim 1 formed on at least one surface of the optical film.
10. The optical member according to claim 9 , wherein the optical film comprises an electromagnetic wave-shielding optical film.
11. An optical display device comprising the porous adhesive film according to claim 1 .
12. The porous adhesive film according to claim 1 , wherein the peel strength is measured by laminating a corona-treated PET film on each of two opposing surfaces of the adhesive film.