Multi-layered elastomer-based liners

A method of making a coated substrate, the method comprising:

• applying a first liquid elastomer to a substrate at a first fluid temperature of about 100 degrees Fahrenheit to about 200 degrees Fahrenheit to form a first elastomer coating comprising a first elastomer selected from the group consisting of a polyurea, a polyurethane, a polyurea-polyurethane copolymer, and combinations thereof;
• and
• applying a second liquid elastomer to the first elastomer coating at a second fluid temperature of about 100 degrees Fahrenheit to about 200 degrees Fahrenheit during a time of about 5 seconds to about 5 minutes after forming the first elastomer coating to form a second elastomer coating disposed on the first elastomer coating, the second elastomer coating is substantially free of sulfur, wherein the second fluid temperature is the same as or different than the first fluid temperature, the first elastomer is the same as or different than the second elastomer, and the second elastomer coating comprises a polyurea-polyurethane copolymer having a hardness (shore D) of about 55 D to about 65 D according to ASTM D-2240, a tear resistance of about 400 PLI to about 800 PLI according to ASTM D-624, a tensile strength of about 2,000 PSI to about 4,000 PSI according to ASTM D-412, and an elongation of about 500% to about 750% according to ASTM D-412.