Intumescent coating compositions effective at low temperatures

A flexible resin system for epoxy intumescent coating compositions comprising:

• at least one epoxy resin and an polyacetatoacetate (AcAc) functional polymer combined with an amine functional curing agent to form a cured flexible resin system that cures within 24 hours at 23° C. with a shore D hardness of at least 2.5;
• wherein the AcAc functional polymer includes at least one terminal AcAc unit as follows:
• in which R2 is —CH2— and R3 is —CH3;
• wherein the cured flexible resin system:
• (i) when equilibrated to −60° C., does not crack after a manual bend test, and (ii) when immersed in water for at least 5 days, gains less than 7.5 wt. % (relative to a dry weight of the coating prior to being immersed);
• and
• wherein the amine functional curing agent includes polytetramethylene ether glycol-based polyether amines having an H eq wt between 500 and 770.