Thermal insulating structures

In combination with a substrate for use subsea, a thermal insulating structure applied to the substrate and for use subsea, the thermal insulating structure including comprising:

• a flexible inner tie coat which is bonded to the substrate, the tie coat consisting of the reaction product of a first material and a second material, the first material consisting of respective amounts of a cold curing phenolic resin and an anti cissing agent, and respective amounts of materials selected from the group consisting of a plasticizer, a silane coupling agent, fumed silica, cenospheres, water, and a dispersion aid, and the second material consisting of a partial phosphate ester and respective amounts of materials selected from the group consisting of a cure accelerator and water;
• a foam insulating layer which is the reaction product of a first material including a cold cure phenolic syntactic resin and a second material including a partial phosphate ester and which insulating layer includes between 15 and 30% by weight cenospheres and a nitrile butadiene rubber flexibilizer up to a maximum of 20% by weight;
• and an outer protective layer which is the reaction product of a first material including a cold cure phenolic resin and a second material including a partial phosphate ester, the outer protective layer having a greater thickness than the inner tie coat layer.