A kind of preparation method of disposable polylactic acid high temperature resistant cup cover

Abstract

The invention discloses a preparation method of a disposable polylactic acid high temperature resistant cup cover. The cup cover comprises following components in parts by weight: 73.8 to 86.5 parts of PLLA, 5 to 10 parts of PGA, 8 to 15 parts of talcum powder, 0.1 to 0.6 part of aluminum-titanium coupling agent, and 0.4 to 0.6 part of food grade white oil. The preparation method comprises following steps: adding talcum powder with a predetermined weight into a high speed stirring machine, then adding an aluminum-titanium coupling agent; then sequentially adding prepared PLLA, PGA, and food grade white oil into the high speed stirring machine; adding the mixture into a double screw extruder with a length / diameter ratio of 48;1, carrying out extruding, stretching, cooling, and slicing to obtain PLLA modified resin particles; adding PLLA modified resin particles into a single screw extruder with a length / diameter ratio of 44:1, carrying out extruding and sheeting to obtain PLLA sheets; heating and baking obtained PLLA sheets by a positive-negative pressure plastic thermo-forming machine, and then carrying out isothermal crystallization, moulding, punching, and cutting to obtain the PLLA heatproof disposable hot-drink cup cover. PGA and PLLA are blended together, the phenomenon that other micromolecular nucleating agents are easily volatilized or precipitated out is avoided, and the application safety is largely improved.

Description

technical field [0001] The invention relates to the field of polymer materials, in particular to a method for preparing a disposable polylactic acid high-temperature resistant cup cover. Background technique [0002] Polylactic acid is a natural antibacterial biodegradable polymer material with abundant and renewable raw materials. Its excellent performance can be applied in many fields such as injection molding, blister molding, blow molding, and injection blow molding. However, the glass transition temperature of ordinary polylactic acid is between 55-60°C, and the heat distortion temperature is also very low, which cannot be concealed from the needs of daily life. In order to improve the heat-resistant temperature of polylactic acid products, domestic and foreign scholars have done a lot of work, mainly including blending, crystallization nucleation and improving the crystallinity of polylactic acid. As far as blending is concerned, it is reported in the literature that ...

AI Technical Summary

Problems solved by technology

As far as blending is concerned, it is reported in the literature that PLLA / PMMA, PLLA / PC alloys, etc. are prepared by blending PLLA with other heat-resistant non-biodegradable materials PMMA, PC, etc. This method obtains PLLA modified materials. The PMMA or PC components cannot be biodegraded, which loses the meaning of degrading the material itself

In addition, small molecule organic nucleating agents are added to PLLA, such as hydrazide compounds, amide compounds and phenylphosphonates, etc., but small molecule nucleating agents themselves do not meet the food contact conditions, and the resulting products are not Use to protect human health

[0003] The existing high-temperature-resistant polylactic acid materials are mainly made by adding a small molecule nucleating agent to the PLLA material, and then isothermally crystallizing in the injection mold to obtain high-temperature-resistant products. This method has a long molding cycle, usually 25-45 hours per cycle. seconds, the production cost is high, and the small molecule nucleating agent is easy to precipitate, which is not good for human health