Full-continuous polylactic acid production equipment and technological process

Abstract

The invention relates to full-continuous polylactic acid production equipment and a technological process. The full-continuous polylactic acid production equipment comprises a first polymerization kettle, a condenser, a second polymerization kettle, a third polymerization tower, a fourth polymerization tower, a monomer removal kettle, a vacuum unit, an underwater granulator and a vacuum packagingmachine. A reflux condenser is arranged at the top of the first polymerization kettle; the first polymerization kettle is connected with an inlet of a first three-way valve through a melt gear pump; an outlet of the first three-way valve is respectively connected with inlets of the second polymerization kettle and a first four-way valve; the second polymerization kettle adopts a special stirring heat tracing form and is connected with an inlet of the first four-way valve through a gear pump; an outlet of the first four-way valve is respectively connected with inlets of the third polymerizationtower and a second four-way valve; the third polymerization tower is connected with an inlet of the second four-way valve through a gear pump; an outlet of the second four-way valve is respectively connected with the fourth polymerization tower and a second three-way valve; the fourth polymerization tower is connected with an inlet of the second three-way valve through a gear pump; an outlet of the second three-way valve is connected with the monomer removal kettle; the top of the monomer removal kettle is connected with the vacuum unit, and the bottom of the monomer removal kettle is sequentially connected with the underwater granulator and the vacuum packaging machine. The full-continuous polylactic acid production equipment is high in automation degree, the reaction temperature of eachkettle can be independently operated, the process adjustment range is large, and the production of differential polylactic acid can be realized.

Description

technical field [0001] The invention belongs to the field of fully biodegradable materials in the polymer industry, and in particular relates to a production equipment and process flow of fully continuous polylactic acid. Background technique [0002] The synthesis of poly-L-lactic acid (PLLA) has two processes: ring-opening polymerization (ROP) and direct polycondensation (DPc). The process of synthesizing polylactic acid by DPc method is relatively simple, but it is difficult to remove the generated water in the late stage of polymerization reaction by DPc method, so it cannot synthesize ultra-high molecular weight PLLA. The ROP process requires the use of high-purity lactide monomers, and the presence of trace impurities will affect the reproducibility of the polymerization reaction. However, this process can synthesize PLLA from low molecular weight to ultra-high molecular weight, and the yield is high. If it can be achieved from low molecular weight Controlled synthesi...

AI Technical Summary

Problems solved by technology

The poor fluidity and easy degradation of high molecular weight polylactic acid melts are also important reasons for limiting the synthesis of high molecular weight polylactic acid.

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