Protective film

A protective film having a pressure-sensitive adhesive layer, wherein the pressure-sensitive adhesive layer comprises a pressure-sensitive adhesive base resin, a multifunctional cross-linking agent, a curing retardant, a polyorganosiloxane satisfying Formula 1 below and a metal salt:

• wherein, n is any one number in a range of 0 to 1500, R1 to R8 are the same or different from each other and each independently hydrogen, an alkyl group, an alkoxy group, an alkynyl group or an alkylene oxide, at least one of R1, R2, R3, R6, R7, or R8 is hydrogen, or an alkynyl group, and at least one of R1 to R8 is an alkylene oxide,
• wherein the polyorganosiloxane has a weight average molecular weight of 10,000 to 100,000,
• wherein the pressure-sensitive adhesive base resin comprises a (meth) acrylic acid ester monomer as a polymerized unit,
• wherein the pressure-sensitive adhesive layer contains the polyorganosiloxane in an amount of 0.01 to 0.9 parts by weight relative to 100 parts by weight of the pressure-sensitive adhesive base resin,
• wherein the multifunctional cross-linking agent comprises a mixture of an aliphatic linear polyvalent NCO and an aliphatic cyclic polyvalent NCO in a weight ratio of 6:4 to 9:1, and the mixture comprises 8 to 20% by weight of NCO,
• wherein the curing retardant is β-diketone,
• wherein the metal salt forms a chelate with the polyorganosiloxane, and
• wherein the metal salt comprises an alkaline earth metal.