Method and device for directly preparing polylactic acid foam product from polylactic acid polymer melt

Abstract

The invention provides a method and a device for directly preparing a polylactic acid foam product from a polylactic acid polymerization melt. The method and the device for directly preparing the polylactic acid foam product from the polylactic acid polymerization melt comprises the steps of polylactic acid melt preparation, material feeding and secondary extruding treatment. In the secondary extruding treatment, the outlet pressure of a first-stage double-screw extruder is 15-17 MPa, the material feeding speed of the polylactic acid polymerization melt is 250 kg / h, the foam auxiliary feedingspeed is 7.5-10 kg / h, and the foaming gas feeding speed is 2.8-7.5 L / h. The method and the device for directly preparing the polylactic acid foam product from the polylactic acid polymerization melt,provided by the invention, have the advantages that an influence on the foaming performance is avoided due to no need of processes such as water cooled pelletizing, repeated drying cooling and heating, melting and mixing; the foaming performance can be guaranteed; the quality can also be guaranteed; the energy consumption is saved by about 1 / 3 or above; the foaming multiplying power of an obtainedproduct is adjusted by 3-25 times; the degree of crystallinity is 40.3-48.5%; the tensile strength is 8.7-19.6 MPa; and the apparent density is 0.05-0.4 g / cm<3>.

Description

technical field [0001] The invention relates to a method and a device for directly preparing foamed products from a polylactic acid polymer melt, and belongs to the technical field of polymer material applications. Background technique [0002] In recent years, the explosive growth of the express delivery and takeaway industries has not only brought a lot of convenience to people's lives, but also brought about increasingly prominent packaging problems. The big data of Chinese food delivery released by the food delivery platform "Ele.me" shows that the number of users in the Chinese market has reached 600 million. In 2016, there were at least 400 million takeaways flying in the streets of China every week, and at least 400 million disposable packaging boxes were produced. With 400 million plastic bags and 400 million discarded disposable tableware, how to deal with takeaway garbage has become an urgent problem to be solved in today's society. [0003] Polylactic acid is a f...

AI Technical Summary

Problems solved by technology

To sum up, the existing patents for preparing foams from polylactic acid all use polylactic acid resin slices, which are dried, modified and granulated, dried again, cooled, dried, or directly extruded / injected / kettle pressured after modification The way of foaming, polylactic acid needs to go through multiple heating and cooling temperatures and melt mixing, the process is complicated and the cost is high

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