A thermal insulation layer of the present disclosure includes a binder resin. The binder resin contains a plurality of aggregates. The aggregate has a plurality of primary inorganic nanoparticles with hydrophobic functional groups on their surfaces and at least one pore formed by being surrounded by these primary inorganic nanoparticles. A coating liquid for forming the thermal insulation layer of the present disclosure includes the plurality of aggregates and a plurality of binder resin particles in solvent. The solvent contains water and alcohol. A ratio of the alcohol to the entire solvent is less than 46% by volume. In a method of manufacturing the thermal insulation layer of the present disclosure, the coating liquid is coated in a layered manner on a substrate, and then, the coated layer is dried to form the thermal insulation layer.

This disclosure provides a method of applying a first coating composition and a second coating composition to a substrate. The method includes providing the substrate defining a first target area and a second target area which define a gap there between of from greater than 0 and up to less than about 2 mm; applying the first coating composition via a first high transfer efficiency applicator to the first target area at a wet film thickness of from about 5 to about 150 microns; and applying the second coating composition via a second high transfer efficiency applicator to the second target area at a wet film thickness of from about 5 to about 150 microns to form a continuous layer of a combination of the first and second coating compositions that extends across the gap and also extends across at least an additional portion of the substrate.