| 摘要 |
<p>PROBLEM TO BE SOLVED: To recover a starting monomer industrially in good efficiency, short time and a high yield by dispersing a thermoplastic polyester resin in a melting state in liquid of a specified temperature or in water of high temperature and high pressure in a supercritical state to perform a hydrolysis reaction. SOLUTION: A depolymerization method uses liquid at 250-450 deg.C or water of high temperature and high pressure in a supercritical state. For a thermoplastic polyester resin, polyethylene terephthalate is specifically preferable. A weight ratio of water of high temperature and high pressure provided into a reactor to the resin is usually 2-10. The using reactor may be either a batch or continuous system. As for a procedure which disperses the thermoplastic polyester resin in a melting state in water of high temperature and high pressure, a static dispersing or a forced dispersing means can be used independently or plurally or in combination with them. An average particle size of the resin dispersed into water of a high temperature and high pressure in a melting state is preferably not more than 5 mm. The residence time in the reactor is controlled usually from not more than 20 min to not less than 1 sec.</p> |
