A peelable coating system, comprising: a first composition comprising an aqueous polymer dispersion or a solvent-based polymer, the first composition being used to form a first coating; and a second composition that is a coating composition, the second composition being used to form a second coating; wherein, said coating composition, comprising: a compound containing an isocyanate-reactive group, wherein the isocyanate-reactive group functionality of the compound containing an isocyanate-reactive group is not less than 2, the compound containing an isocyanate-reactive group comprising an amino-containing compound, the amino-containing compound is a sterically hindered aliphatic secondary diamine having a structure of formula I: wherein R is a (cyclo)alkylene group having 2 to 16 carbon atoms, and preferably a (cyclo)alkylene group with 1 to 3 carbon atoms being substituted by an etheroxy group or a tertiary amino group; and R' is an isocyanate non-reactive organic group, preferably one or more of the following: diisopropylmethyl and t-butyl; a polyisocyanate having an average isocyanate group functionality of not less than 2.8, wherein in the case polyisocyanate is a mixture of polyisocyanates, the isocyanate group functionality of the polyisocyanate is the average isocyanate group functionality of the plurality of polyisocyanates, wherein the equivalence ratio of the isocyanate group to the isocyanate-reactive group is from 0.5: 1 to 10: 1; and an organic solvent. a first composition comprising an aqueous polymer dispersion or a solvent-based polymer, the first composition being used to form a first coating; and a second composition that is a coating composition, the second composition being used to form a second coating; wherein, said coating composition, comprising: a compound containing an isocyanate-reactive group, wherein the isocyanate-reactive group functionality of the compound containing an isocyanate-reactive group is not less than 2, the compound containing an isocyanate-reactive group comprising an amino-containing compound, the amino-containing compound is a sterically hindered aliphatic secondary diamine having a structure of formula I: wherein R is a (cyclo)alkylene group having 2 to 16 carbon atoms, and preferably a (cyclo)alkylene group with 1 to 3 carbon atoms being substituted by an etheroxy group or a tertiary amino group; and R' is an isocyanate non-reactive organic group, preferably one or more of the following: diisopropylmethyl and t-butyl; a polyisocyanate having an average isocyanate group functionality of not less than 2.8, wherein in the case polyisocyanate is a mixture of polyisocyanates, the isocyanate group functionality of the polyisocyanate is the average isocyanate group functionality of the plurality of polyisocyanates, a compound containing an isocyanate-reactive group, wherein the isocyanate-reactive group functionality of the compound containing an isocyanate-reactive group is not less than 2, the compound containing an isocyanate-reactive group comprising an amino-containing compound, the amino-containing compound is a sterically hindered aliphatic secondary diamine having a structure of formula I: wherein R is a (cyclo)alkylene group having 2 to 16 carbon atoms, and preferably a (cyclo)alkylene group with 1 to 3 carbon atoms being substituted by an etheroxy group or a tertiary amino group; and R' is an isocyanate non-reactive organic group, preferably one or more of the following: diisopropylmethyl and t-butyl; a polyisocyanate having an average isocyanate group functionality of not less than 2.8, wherein in the case polyisocyanate is a mixture of polyisocyanates, the isocyanate group functionality of the polyisocyanate is the average isocyanate group functionality of the plurality of polyisocyanates, wherein the equivalence ratio of the isocyanate group to the isocyanate-reactive group is from 0.5: 1 to 10: 1; and an organic solvent.