Laminated hard coating film
Disclosed herein is a laminated hard coating film, which exhibits high hardness and excellent properties without a supporting substrate. The laminated hard coating film can find useful applications in various fields thanks to its excellent hardness, scratch resistance, transparency, durability, light resistance, light transmittance, and the like.
1. A laminated hard coating film, comprising:
a single hard coating layer including a photocurable crosslinking copolymer and inorganic particles dispersed in the photocurable crosslinking copolymer; and
a substrate laminated on at least one side of the hard coating layer,
wherein the photocurable crosslinking copolymer includes 5 to 20 weight parts of a photocurable elastic polymer and 80 to 95 weight parts of a tri- to hexa-functional acrylate monomer based on 100 weight parts thereof,
wherein the laminated hard coating film exhibits a pencil hardness of 7H or more at a load of 1 kg, and
wherein when the laminated hard coating film is disposed on a plane after exposure to a temperature of 50° C. or more at a humidity of 80% or more for 70 hours or more, each edge or side of the laminated hard coating film is spaced apart from the plane by 1.0 mm or less, maximally.
2. The laminated hard coating film of claim 1 , wherein the photocurable elastic polymer has an elongation of 15 to 200%, as measured according to ASTM D638.
3. The laminated hard coating film of claim 1 , wherein the photocurable elastic polymer comprises at least one selected from the group consisting of a polycaprolactone, a urethane acrylate polymer and a polyrotaxane.
4. The laminated hard coating film of claim 3 , wherein the polyrotaxane comprises a cyclic moiety (macrocycle) in which lactone compounds with a (meth)acrylate moiety conjugated to the end thereof are bonded each other; a thread moiety held within the macrocycle; and stoppers provided at both ends of the thread moiety so as to prevent dissociation of the macrocycle.
5. The laminated hard coating film of claim 1 , wherein the hard coating layer includes 40 to 90 weight parts of the photocurable crosslinking copolymer and 10 to 60 weight parts of the inorganic particles, based on 100 weight parts thereof.
6. The laminated hard coating film of claim 1 , wherein the inorganic particles have a particle diameter of 100 nm or less.
7. The laminated hard coating film of claim 1 , wherein the inorganic particles include at least one selected from the group consisting of silica nanoparticles, aluminum oxide nanoparticles, titanium oxide nanoparticles and zinc oxide nanoparticles.
8. The laminated hard coating film of claim 1 , wherein the tri- to hexa-functional acrylate monomer includes at least one selected from the group consisting of trimethylolpropane triacrylate (TMPTA), trimethylolpropane ethoxytriacrylate (TMPEOTA), glycerin propoxylated triacrylate (GPTA), pentaerythritol tetraacrylate (PETA), and dipentaerythritol hexaacrylate (DPHA).
9. The laminated hard coating film of claim 1 , wherein the substrate includes at least one selected from the group consisting of a plastic resin film, an adhesive film, an releasable film, an electrically conductive film, an electrically conductive layer, a curable resin layer, a non-conductive film, a metal mesh layer, and a patterned metal layer.
10. The laminated hard coating film of claim 9 , wherein the plastic resin film includes of at least one selected from polyethyleneterephtalate (PET), ethylene vinyl acetate (EVA), cyclic olefin polymer (COP), cyclic olefin copolymer (COC), polyacrylate (PAC), polycarbonate (PC), polyethylene (PE), polymethylmethacrylate (PMMA), polyetheretherketon (PEEK), polyethylenenaphthalate (PEN), polyetherimide (PEI), polyimide (PI), triacetylcellulose (TAC), MMA (methyl methacrylate) and a fluoro-polymer.
11. The laminated hard coating film of claim 1 , wherein the laminated hard coating film does not crack when a 22g steel ball is freely dropped 10 times thereon from a height of 50 cm.
12. The laminated hard coating film of claim 1 , wherein the laminated hard coating film allows two or less scratches to appear thereon after it is doubly rubbed 400 times with a steel wool #0000 under a load of 500 g.
13. The laminated hard coating film of claim 1 , having a light transmittance of 91% or more, a haze of 0.4 or less and a color b* value of 1.0 or less.
14. The laminated hard coating film of claim 1 , wherein the laminated hard coating film has a color b* value after exposure to UV B for 72 hrs which differs from a pre-exposed, color b* value by 0.5 or less.
15. The laminated hard coating film of claim 1 , wherein the hard coating layer has a thickness of 50 to 500 μm.
16. The laminated hard coat film of claim 1 , wherein the single hard coating layer is formed by photocuring on a releasable film, and the releasable film is detached after photocuring.