System and method for manufacturing polyamic acid, and system and method for manufacturing polyimide

A polyamic acid solution manufacturing method for manufacturing a polyamic acid solution using, as raw materials, a first solution in which a polyaddition-type first polymerizable compound is dissolved and a second solution in which a polyaddition-type second polymerizable compound that reacts with the first polymerizable compound through polyaddition is dissolved, the polyamic acid solution manufacturing method comprising:

• a first supply step of supplying the first solution;
• a second supply step of supplying the second solution;
• a first combining step of producing a first combined solution by combining the first solution and the second solution in a hermetically sealed tube without contacting with a gas phase;
• and
• a first reaction step of mixing, in a hermetically sealed tube, the first combined solution not in contact with gas to cause a polymerization reaction between the first polymerizable compound and the second polymerizable compound, thereby producing a first polymerization solution in which a polyamic acid is dissolved,
• wherein in the first combining step, the first combined solution is produced by combining the first solution and the second solution in a connecting part connecting a tubular liquid transfer line through which the first solution passes, a tubular liquid transfer line through which the second solution passes, and a tubular liquid transfer line through which the first combined solution passes, and
• wherein in the first reaction step, the first combined solution is mixed by passing through a static-type mixer, and thereby the first polymerization solution is produced, wherein a first viscosity information of the first polymerization solution;
• and controlling the supplying the first solution and/or the supplying the second solution with the first viscosity information.