Photocurable composition for optical bonding agent, image display device applying same, and method for manufacturing image display device

1. A photocurable composition for an optical bonding agent, comprising:

an acrylic photocurable compound; and

a plasticizer,

wherein the acrylic photocurable compound comprises a monofunctional acrylic photocurable monomer and a (meth)acrylate-based photocurable polymer having a weight average molecular weight of 50,000 g/mol or less, and

the monofunctional acrylic photocurable monomer is comprised in an amount of 5 wt % to 15 wt %-in the photocurable composition for the optical bonding agent,

wherein the (meth)acrylate-based photocurable polymer is one selected from the group consisting of urethane (meth)acrylate, polyester (meth)acrylate, epoxy (meth)acrylate, polyether (meth)acrylate, polybutadiene (meth)acrylate, and a combination thereof, and

wherein the (meth)acrylate-based photocurable polymer comprises both a monofunctional (meth)acrylate-based photocurable polymer and a difunctional (meth)acrylate-based photocurable polymer,

wherein the monofunctional acrylic photocurable monomer is lauryl (meth)acrylate, and

wherein the curing shrinkage is less than or equal to 1.2%.

2. The photocurable composition of claim 1 , wherein the monofunctional acrylic photocurable monomer has a glass transition temperature (Tg) of −60° C. to 100° C.

3. The photocurable composition of claim 1 , wherein the plasticizer comprises one selected from the group consisting of an epoxy-based plasticizer, a fatty acid ester-based plasticizer, a polyester-based plasticizer, a polybutadiene-based plasticizer, and a combination thereof.

4. The photocurable composition of claim 1 , wherein a weight ratio of the monofunctional acrylic photocurable monomer to the plasticizer is 1:3 to 1:20.

5. The photocurable composition of claim 1 , further comprising:

a photoinitiator.

6. The photocurable composition of claim 5 , wherein the photoinitiator is one selected from the group consisting of a hydroxyketone-based compound, a phenylglyoxylate-based compound, a benzyldimethylketal-based compound, an α-aminoketone-based compound, a monoacylphosphine-based compound, a bisacylphosphene-based compound, a phosphine oxide-based compound, a metallocene-based compound, an iodonium salt, and a combination thereof.

7. The photocurable composition of claim 1 , further comprising:

one additive selected from the group consisting of a lubricant, a leveling agent, a softener, an antioxidant, an anti-aging agent, a light stabilizer, an ultraviolet absorber, a polymerization inhibitor, and a combination thereof.

8. The photocurable composition of claim 1 , wherein the photocurable composition for the optical bonding agent has a viscosity of 2,000 cps to 40,000 cps at 25° C.

9. The photocurable composition of claim 1 , wherein the photocurable composition for the optical bonding agent is a liquid solvent-free type.

10. An image display device comprising:

an image display part;

a bonding layer comprising a photo-cured product of the photocurable composition for the optical bonding agent according to claim 1 ; and

a protective part.

11. The image display device of claim 10 , wherein the bonding layer has a thickness of 50 μm to 300 μm.

12. The image display device of claim 10 , wherein the image display part is a liquid crystal display (LCD).

13. The image display device of claim 10 , wherein the protective part is a glass substrate or a transparent plastic substrate.

14. A method for manufacturing an image display device, the method comprising:

applying the liquid photocurable composition for the optical bonding agent according to claim 8 onto an image display part, and subsequently, closely adhering a protective part onto the applied photocurable composition for the optical bonding agent; and

forming a bonding layer by photo-curing the liquid photocurable composition for the optical bonding agent.