Copolymer rubber composition, rubber foamed product, and automotive sealant

A method for producing a copolymer rubber composition comprising:

• a copolymer rubber (1);
• and
• a copolymer rubber (2), as a rubber component,
• wherein the content of the copolymer rubber (1) is 60% by weight or more and 75% by weight or less, and the content of the copolymer rubber (2) is 40% by weight or less and 25% by weight or more, based on 100% by weight of the total of the copolymer rubber (1) and the copolymer rubber (2);
• and [iodine value of the copolymer rubber (1)−iodine value of the copolymer rubber (2)] is 5 or more and 30 or less, and
• wherein,
• the copolymer rubber (1) is an ethylene-a-olefin-nonconjugated polyene copolymer rubber wherein the content of a monomer unit based on ethylene is 50 mol % or more and 70 mol % or less;
• the content of a monomer unit based on α-olefin is 50 mol % or less and 30 mol % or more (provided that the total of the monomer unit based on ethylene and the monomer unit based on α-olefin is 100 mol %);
• and the iodine value is 15 or more and 45 or less, and
• the copolymer rubber (2) is an ethylene-α-olefin-nonconjugated polyene copolymer rubber wherein the content of a monomer unit based on ethylene is more than 70 mol % and 95 mol % or less;
• the content of a monomer unit based on α-olefin is less than 30 mol % and 5 mol % or more (provided that the total of the monomer unit based on ethylene and the monomer unit based on α-olefin is 100 mol %);
• and the iodine value is 10 or more and 30 or less,
• the method comprising
• manufacturing one of the copolymer rubber (1) and the copolymer rubber (2) in a first reaction tank, feeding the one copolymer rubber manufactured in the first reaction tank to a second reaction tank, and
• manufacturing the other copolymer rubber in the second reaction tank,
• wherein the two tanks are coupled in series.