Threaded rod for polymer microcellular foaming injection molding

Abstract

The invention discloses a threaded rod for polymer microcellular foaming injection molding. A threaded rod feeding section, a threaded rod compression section and a threaded rod metering section are arranged in front of the polish rod part of the threaded rod in sequence, and the length of the threaded rod metering section is 1-2 D; a middle non-return valve is arranged in front of the threaded rod metering section, the manner of two semirings disconnected in a ladder shape is adopted, and the two semirings are arranged on the ladder shaft of the threaded rod in a sleeving mode after being aligned; a shearing section and a mixing section are arranged in front of the middle non-return valve in sequence, and the shearing section and the mixing section adopt multiple threads; a reversed multi-thread screw groove is formed in the mixing section; a front non-return valve and a threaded rod head are arranged in front of the mixing section, the front non-return valve is arranged on the ladder shaft of the threaded rod head in a sleeving mode, and the threaded rod head is connected to the front end of the threaded rod through threads. The middle non-return valve is additionally arranged on the threaded rod disclosed by the invention, and the semirings disconnected in the ladder shape are arranged on the integrally designed and processed ladder shaft of the threaded rod in the sleeving mode, so that an injected supercritical fluid foaming agent is prevented from escaping backwards.

Description

technical field [0001] The invention relates to an injection molding screw, in particular to a screw for polymer microcellular foaming injection molding, which is used in injection molding machine systems with special requirements on the screw, such as polymer supercritical fluid microcellular foaming injection molding. Background technique [0002] In the 1980s, scholars at the Massachusetts Institute of Technology (MIT) first proposed and successfully developed microcellular foamed plastic materials. The microcellular foamed plastic material can reduce the weight of the product on the basis of keeping the mechanical properties of the product basically unchanged. At the same time, there is almost no residual stress inside the product, and the warping and deformation of the product can be well suppressed. Compared with unfoamed plastic materials, the density of microcellular foamed plastic materials can be reduced by 5% to 95%, the notched impact strength can be increased by...

AI Technical Summary

Problems solved by technology

For microcellular foam injection molding, it is necessary to inject supercritical fluid into the polymer melt during the plasticization stage, and quickly dissolve and uniformly diffuse in a short time to form a gas-polymer homogeneous solution, while preventing injection The reverse escape of the supercritical fluid, which puts forward new and stricter requirements on the mixing and homogenizing ability of the screw and the intermediate anti-return ability. cannot meet this requirement

[0006] Both Chinese patent documents CN102126274A and CN102205609A realize "improving the mixing effect of the screw and preventing the backflow of the melt from blocking the intake channel" by adding "the front mixing section, the rear mixing section and the rear check ring", but this The technology adopts segmented screw design, using screw connection to increase the mixing section and check ring, which reduces the strength of the screw and increases the processing difficulty and precision. The length range of the mixing section is small, which affects the mixing ability and versatility of the screw

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