Injection molding device and injection molding method of online mixing and preparing high-performance microcellular foaming plastic

Abstract

The invention discloses an injection molding device and an injection molding method of online mixing and preparing high-performance microcellular foaming plastic. The device comprises an extrusion foaming unit, a supercritical fluid transportation unit and an injection foaming unit. A constant temperature box and a granulator are arranged at the output end of the extrusion foaming unit. A discharge port of the granulator is connected with the injection foaming unit. The supercritical fluid transportation unit is respectively connected with the extrusion foaming unit and the injection foaming unit through pipelines. The outlet end of the injection foaming unit is connected with a mold cavity. The method is that materials and supercritical fluid are plasticized, fused, mixed and extruded inside the extrusion foaming unit, strip-shaped stuff is formed after initial foaming, cooled and set, and then granulation is carried out by the granulator to form polymer foaming granules with high entrapped air. The polymer foaming granules are sent into the injection foaming unit and plasticized, fused and mixed with the supercritical fluid, then injected into the mold cavity to carry out second foaming, and the high-performance foaming product is formed.

Description

technical field [0001] The invention relates to a molding technology of microcellular foamed plastics, in particular to an injection molding device and method for preparing high-performance microcellular foamed plastics by on-line compounding. Background technique [0002] Microcellular plastic refers to the cell diameter of 0.1~10μm, cell density of 10 9 ~10 15 piece / cm 3 The new type of foam plastic has the characteristics of light weight and high specific strength, and at the same time has the advantages of good ability to absorb impact loads, heat insulation, sound insulation, buffering, insulation, and anti-corrosion. [0003] The principle of microcellular foam injection molding is to melt and plasticize the resin under a predetermined back pressure, quantitatively inject supercritical nitrogen or carbon dioxide into the molten resin, form a homogeneous solution after further mixing and diffusion, and keep it before entering the mold cavity In this state, the inject...

AI Technical Summary

Problems solved by technology

[0004] However, in the key step of forming a single homogeneous system between the supercritical fluid and the polymer melt, the existing short-time microcellular foaming injection molding cycle, its mixing effect is not ideal

If supercritical nitrogen or carbon dioxide cannot be well dispersed in the polymer melt, it is difficult to obtain foamed parts with ideal structure and performance

Due to the inherent complexity of the injection molding process, the parts obtained by microcellular foaming injection molding often have different pore sizes and unstable cell densities, so that the properties of the foamed samples cannot meet the consistency, stability and quality of industrial production. reliability requirements

In addition, in practical applications, it is often difficult for a single material to meet the requirements of various indicators of comprehensive performance, so filling modification and blending modification technologies are often used

The resulting dispersion of inorganic filler particles and phase separation in multiphase systems are also challenging problems in the application of microcellular injection foam molding

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