Patent ID: 8480843

Claim:
A process for protecting a surface of a metal layer or a metal oxide layer comprising: providing a metal layer or a metal oxide layer, providing a protective film comprising a base material and a pressure-sensitive adhesive layer formed thereon, applying the protective film on the metal layer or the metal oxide layer via the pressure-sensitive adhesive layer, and removing the protective film from the metal layer or the metal oxide layer, wherein the pressure-sensitive adhesive layer comprises a (meth)acrylic polymer and a crosslinking agent, and the crosslinking agent comprises a polyfunctional epoxy compound or a polyfunctional isocyanate compound, wherein the surface of the pressure-sensitive adhesive layer has a contact angle with methylene iodide as measured just after contact, θ 1 , of 70° or smaller and a change in contact angle with methylene iodide through 30-second standing, Δθ, of 8% or less, and wherein the pressure-sensitive adhesive layer has a thickness of 20 μm or less, and wherein the (meth)acrylic polymer is a polymer obtained by the copolymerization of one or more (meth)acrylic esters having an alkyl group having 1 to 18 carbon atoms and one or more copolymerizable modifying monomers selected from the group consisting of (meth)acrylonitrile, vinyl acetate, styrene, maleic anhydride, vinylpyrrolidone, (meth)acrylic esters having a glycidyl group, a dimethylaminoethyl group, or a hydroxyl group, (meth)acrylamide, vinylamine, allylamine, and ethyleneimine.