Method for manufacturing seal body, and seal body

A method for manufacturing a seal body whose main raw material is a compound containing a halogen group-containing monomer as a constitutional unit, the method comprising:

• a mixing step of forming a mixture of the halogen group-containing monomer and a cross-linking agent;
• a mill kneading step of using a mill kneader to knead the mixture using a rotor blade;
• a roll kneading step of using a roll kneader to knead a mill kneaded material obtained by the mill kneading step between a plurality of rolls;
• a pressurizing step of pressurizing a roll kneaded material obtained by the roll kneading step using a press machine, wherein the pressurizing conditions of the pressurizing step include a pressurizing pressure of the press machine in a range of 95 to 105 kgl/cm2, a pressing temperature of 150° C., a pressing time of 1 hour, and a thickness of a pressurized body after pressurizing is adjusted to a thickness of 2 mm;
• a belt-like body forming step of forming a belt-like body from the pressurized body by cutting the pressurized body to form the belt-like body, and
• a press-fixing step of press-fixing one end and the other end of the belt-like body obtained by the belt-like body forming step to form an endless seal body.