Micro-foaming injection-molded screw

Abstract

The invention discloses a micro-foaming injection-molded screw, which mainly comprises a rear screw, a rear positioning ring, a rear non-return ring, a rear mixing section, a front mixing section, a front screw, a front positioning ring, a front non-return ring, and a screw head; the rear mixing section and the front mixing section has skewed slot barriers; a left and a right ends of the mixing sections are provided alternately with four charging troughs and discharging troughs; ribs between the charging and discharging skewed slots have a length less than the diameter of the mixing sections;the rear mixing section adopts a positive skewed slot with the same rotation direction as the screw, and the front mixing section adopts a reverse skewed slot. The screw has greatly improved mixing homogenization effect, and allows supercritical gas to distribute rapidly and uniformly in polymer melt so as to form a stable polymer melt / supercritical gas homogeneous system; meanwhile, a non-return ring is used at the air-inlet position, which can effectively prevent the obstruction of the air-inlet channel due to melt reflux; the novel micro-foamed injection-molded screw is widely applicableto various micro-foaming injection machines.

Description

technical field [0001] The invention relates to an injection molding screw, in particular to a screw suitable for microfoaming injection molding. Background technique [0002] Micro-foaming injection molding technology is a new green injection molding technology developed in the 1980s. By introducing a supercritical gas foaming agent into the melt, the fatigue life of the microcellular foamed plastic obtained can be extended by 5 times, and the fracture toughness It can be increased by nearly 4 times, and the impact strength can be increased by 6 to 7 times. This new type of processing technology has greatly improved the performance of the product, and is a very promising green plastic molding processing technology. [0003] During the molding process, the main function of the screw is to melt and plasticize the solid raw material and transport the melt forward stably. In micro-foaming injection molding, the melt is filled with a supercritical gas foaming agent. The superc...

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Problems solved by technology

[0004] The purpose of the present invention is to propose a micro-foaming injection molding screw, which can overcome the shortcoming of insufficient mixing and homogenizing ability of the traditional screw, greatly improve the mixing and homogenizing effect of the screw, and make the supercritical gas quickly and evenly distributed in the polymer melt In the process, a stable polymer / supercritical gas homogeneous system is formed; at the same time, due to the addition of a non-return structure at the inlet position of the screw, it can effectively prevent the melt backflow from blocking the inlet channel and ensure the continuous stability of the micro-foaming injection process; this This microfoaming injection screw can be widely used in various types of microfoaming injection machines

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