Cure-on-demand liquid sealant composition, process for the preparation thereof and uses thereof

A process for preparing a liquid sealant composition in which the composition comprises

• (a) a polysulphide with an —SH end group,
• (b) a crosslinking agent chosen from ethylenically unsaturated or acetylenically unsaturated compounds, said unsaturated ethylenic or unsaturated acetylenic functions of the crosslinking agent being chemically blocked with a blocking agent, wherein said blocking agent is a diene corresponding to the formula:
• in which:
• the R1 radical and optionally the R4 radical are identical C1-C12 alkyl chains functionalized with at least one ester, ether, ketone or amide function,
• the R2 radical, the R3 radical and, optionally, the R4 radical, if R4 is not a functionalized C1-C12 alkyl chain, are hydrogen atoms,
• X═CH2, O, S, or N—Rx in which Rx is chosen from linear or branched C1-C30 alkyl chains,
• (c) optionally, a catalyst, wherein the process comprises at least the following steps:
• i) synthesizing of a crosslinking agent chosen from ethylenically unsaturated or acetylenically unsaturated compounds, said unsaturated ethylenic or unsaturated acetylenic functions of the crosslinking agent being chemically blocked by Diels-Alder reaction with a blocking agent, optionally in the presence of a catalyst, then
• ii) mixing of the chemically blocked crosslinking agent obtained at the end of step i) with a liquid polysulphide polymer comprising an —SH end group, optionally in the presence of a catalyst, the mixing temperature having to be controlled so as not to exceed the crosslinking agent deblocking temperature.