Micropore foaming agent for polypropylene, microcellular foamed polypropylene composite material and methods for preparing micropore foaming agent for polypropylene and microcellular foamed polypropylene composite material

Abstract

The invention discloses a micropore foaming agent for polypropylene, a microcellular foamed polypropylene composite material and methods for preparing the micropore foaming agent for polypropylene and the microcellular foamed polypropylene composite material. The micropore foaming agent for polypropylene consists of the following components in parts by weight: 9-15 parts of sodium bicarbonate, 21-35 parts of citric acid and 50-70 parts of high polymer material. The microcellular foamed polypropylene composite material consists of the following components in parts by weight: 69-80 parts of polypropylene, 5-10 parts of high density polyethylene, 3-5 parts of nucleating agent, 10-15 parts of inorganic filler, 0.1-1.0 part of heat stabilizer, 0.2-1.5 parts of antioxidant and 0.2-0.8 part of the micropore foaming agent for polypropylene. The preparation methods are simple and low in cost. An economic and environment-friendly foaming system is utilized, the foaming material is an injection molding grade foaming material, so that the limitation of foaming material plates or pipes are broken through; and various physical and mechanical performances of the produced microcellular foamed polypropylene composite material are excellent, and moreover, the density of the material is reduced by 30%.

Description

technical field [0001] The invention relates to a foaming agent, a foamed plastic and a preparation method thereof, in particular to a microcellular foaming agent for polypropylene, a microcellular foamed polypropylene composite material and a preparation method thereof. Background technique [0002] In recent years, polypropylene (referred to as PP) foam material has attracted more attention due to its unique advantages; it is especially popular in the automotive field with the trend of "light weight, energy saving and environmental protection", but PP is a crystalline polymer thing. The foaming temperature range is narrow and the melt strength is low; the low melt strength cannot guarantee the effect of the tensile stress on the cell wall during the growth of the bubbles, resulting in the collapse and rupture of the bubbles; therefore, the obtained cell shape Irregularity, large cell diameter and uneven distribution, when the cells are stressed, they often become the birt...

AI Technical Summary

Problems solved by technology

The currently commonly used chemical foaming methods are mainly divided into three series: one is the AC foaming series, patents CN1944032A, CN1944035A, and CN201110302594.8 all use AC foaming agents to prepare foaming materials, although AC foaming agents have a high foaming rate , the foaming temperature is high, but the controllability of foamed polypropylene is poor, and the cells are uneven. In addition, the AC foaming agent is an azo compound, which has certain toxicity. After the degradation of the AC foaming agent, some substances that pollute the environment will be produced. International has been disabled, so AC blowing agents are not suitable for future development

The second is OBSH-based foaming agents. Although the foaming agent has better performance, it is expensive. At present, the common foaming agent NaHCO3 is 7 yuan / kg, and OBSH is 100 yuan / kg, which is not suitable for competition. The increasingly fierce field of automotive materials

The third is the NaHCO3 system, which is the most economical and environmentally friendly foaming agent, but its foaming temperature is low and its compatibility is poor, so it is difficult to produce closed cells, uniform cell distribution, Micro-foamed polypropylene material with excellent physical and mechanical properties

Patents CN200810196062.9 and CN200810196063.3 are prepared by adding NaHCO3 foaming agent and adjusting the screw and temperature to make non-woven foamed sheets. Although the process is simple, there are few types of products, only Pipes or plates are far from satisfying the automotive field that requires high automotive interior styles; patent CN101792554A discloses the preparation of foamed polypropylene by blending polypropylene materials and foam masterbatches, but in the preparation method, polypropylene and foamed The mixing extrusion temperature of masterbatch is 140-160℃, and the extrusion temperature of general polypropylene material is above 200℃, so this technology is not practical

[0006] In the above-mentioned existing disclosed technology, although physical foaming is simple, it has very high requirements on equipment and technology. In addition, the pore size and closed Pores are difficult to control. The foaming controllability of the AC foaming system in the chemical foaming method is poor, and it has environmental impact; OBSH is expensive and not suitable for large-scale application; NaHCO3 system, it is a It is the most economical and environmentally friendly foaming agent, but its foaming temperature is low and its compatibility is poor. It is difficult to produce micro-foamed polypropylene materials with closed cells, uniform cell distribution, and excellent physical and mechanical properties.

Currently only extruded or molded microfoam pipes or sheets are available