Nylon copolymers containing dimeric acid comonomers

1. Field of the Invention A method for preparing a nylon 6 copolymer containing dimeric acid comonomers. The method includes reacting 80.0˜99.9 mol % of caprolactam, 0.1˜3.0 mol % of dimeric acid and 0.1˜3.0 mol % of 2-methyl-1,5-pentadiamine in a polymerization reaction. Moreover, the invention provides a method for preparing a nylon 66 copolymer containing dimeric acid comonomers, which comprising reacting 60.0˜90 mol % of hexadiacid and hexadiamine, 0.1˜3.0 mol % of dimeric acid and 0.1-3.0 mol % of 2-methyl-1,5-pentadiamine in a polymerization reaction. The reaction temperature for both of the methods are at 200˜280° C.