Method for making a dual curable ethylene propylene diene polymer rubber coating using a photoinitiator and a peroxide

A method for making a durable ambient light curable waterproof liquid rubber formulation with a volatile organic compound content of less than 450 grams per liter, comprising:

• a. blending in a closed vessel forming a solution, a first portion of ethylene propylene diene terpolymer (EPDM) with a first portion of solvent, wherein the ethylene propylene diene terpolymer (EPDM) is 50 weight percent to 99 weight percent of a total amount of ethylene propylene diene terpolymer used in a resulting durable ambient light curable waterproof liquid rubber formulation and the first portion of solvents is 33 weight percent to 67 weight percent of a total amount of solvent used in the resulting durable ambient light curable waterproof liquid rubber formulation;
• b. mixing the solution in a high shear mixer for at least 10 to 240 minutes at a temperature from 20 degrees Celsius to 50 degrees Celsius forming a high viscosity solution;
• c. adding a second portion of ethylene propylene diene terpolymer (EPDM) to the high viscosity solution, wherein the second portion of ethylene propylene diene terpolymer (EPDM) is 0.1 weight percent to 50 weight percent of the total amount of ethylene propylene diene terpolymer (EPDM) used in the resulting durable ambient light curable waterproof liquid rubber formulation;
• d. adding a second portion of solvent to the high viscosity solution wherein the second portion of solvent is 33 weight percent to 80 weight percent of a total amount of solvent used in the resulting durable ambient light curable waterproof liquid rubber formulation;
• e. blending the high viscosity solution for 10 minutes to 120 minutes at a temperature from 20 degrees Celsius to 50 degrees Celsius to form a low viscosity liquid intermediate rubber formulation with a saturated backbone of propylene, a saturated backbone of ethylene, and an unsaturated diene with ultra violet activated sites capable of crosslinking with or reacting with a free radical or a free radical on another terpolymer;
• f. adding 0.1 weight percent to 10 weight percent of a photoinitiator devoid of thermally activated accelerators to the low viscosity liquid intermediate rubber formulation based on the total weight of the resulting dual curable waterproof liquid rubber formulation to generate free radicals that react with the active sites of the unsaturated diene, forming a low viscosity liquid intermediate rubber formulation with photoinitiator;
• g. adding 0.1 to 15 weight percent of a peroxide to the a low viscosity liquid intermediate rubber formulation with photoinitiator, wherein the peroxide comprises at least one of:
• a peroxyketal, a peroxyester, a dialkyl peroxide, a peroxy carbonate, or an azo initiator forming a dual cure liquid;
• and
• h. blending the dual cure liquid at a low shear for 10 minutes to 120 minutes at a temperature from 20 degrees Celsius to 50 degrees Celsius in the absence of light forming the dual curable waterproof liquid rubber formulation, wherein the dual curable waterproof liquid rubber formulation is adapted to form a waterproof seal on a substrate in the presence of ultraviolet light and heat.