Polylactic acid foaming composite material as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of biodegradable foaming materials, and discloses a polylactic acid foaming composite material as well as a preparation method and application thereof. The polylactic acid foaming composite material comprises the following components in parts by weight: 100 parts of polylactic acid resin, 5-15 parts of other biodegradable materials, 0.5-3 parts of a bio-based nucleating agent, 0.5-4 parts of a chain extender and 0.1-1 part of a lubricant. The preparation method comprises the steps of mixing, extruding, drawing and pelletizing the components to prepare a polylactic acid foaming master batch; and putting the polylactic acid foaming master batch into a high-pressure reaction kettle, introducing a fluid serving as a foaming agent into the high-pressure reaction kettle, controlling the temperature of the high-pressure reaction kettle to be 40-200 DEG C and the pressure of the high-pressure reaction kettle to be 8-20 MPa, keeping the temperature and the pressure for 30-120 minutes, releasing gas in the reaction kettle, reducing the pressure to normal pressure, and taking out polylactic acid foaming particles from the reaction kettle, so as to obtain the particles, namely, the polylactic acid foaming composite material.

Description

technical field [0001] The invention belongs to the technical field of biodegradable foaming materials, in particular to a polylactic acid foaming composite material and its preparation method and application. Background technique [0002] Polylactic acid (PLA), as a renewable polymer, has good physical properties and heat resistance compared with other biomaterials, and is the most likely biodegradable material to replace traditional petroleum-based polymers. However, due to the slow crystallization speed and low melt strength of polylactic acid itself, its products still cannot replace conventional polyolefin products in terms of mechanical properties and heat resistance. In addition, the density of polylactic acid is much higher than that of polyolefin, so the weight of polylactic acid products will increase by 30-40% compared with other polyolefin products, which is not conducive to energy saving and environmental protection, and the price is much higher than polyolefin....

AI Technical Summary

Problems solved by technology

[0003] Polylactic acid foam is an ideal packaging material. At present, there are three main processing technologies in the manufacture of PLA foam. Extrusion casting is the most widely used method to prepare PLA foam packaging materials. However, due to the low melt strength of PLA itself , is highly sensitive to shear, and high-shear production may easily lead to unstable melt flow and rupture, which is not suitable for high-speed production; foam injection molding has low material cost, high dimensional stability, high energy efficiency, and short time period and other advantages, but most of the products have the problem of low porosity, which cannot achieve the purpose of lightweight products; and supercritical foaming technology is a green and advanced processing technology, using supercritical CO 2 , N 2 The physical foaming method based on physical foaming agent such as physical foaming agent is superior to the chemical foaming method because of its environmental friendliness and operation controllability, and it has been paid more and more attention. It is characterized in that the polylactic acid resin particles Always maintain the particle state, no particle fusion and adhesion phenomenon, controllable foaming ratio, simple foaming process

However, the melt strength of polylactic acid resin is low, it is difficult to obtain foamed products with stable shape, and it is also difficult to obtain high expansion ratio

There are still technical difficulties in preparing polylactic acid foam materials with excellent performance through commercialized general-purpose polylactic acid resins

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