Apparatus and method for extrusion moulding of supercutical-fluid micropore plastic

Abstract

The invention discloses an apparatus and a method for extrusion moulding of supercritical-fluid micropore plastic. The apparatus comprises an electric cabinet, a vibration exciter, a power unit, a plasticizing mixing unit, a supercritical fluid conveying unit and a moulding unit; the vibration exciter, the power unit, the plasticizing mixing unit and the moulding unit are in successive connection; the supercritical fluid conveying unit is arranged on the plasticizing mixing unit; and the vibration exciter, the power unit and the plasticizing mixing unit are all independently connected with the electric cabinet. The method comprises that the power unit drives a screw to rotate, the vibration exciter drives the screw to make periodic vibration at the axial direction; a material is plasticized and fused under the dual effects of shear force field and vibration force field of the screw; at the same time, the supercritical fluid conveying unit injects a supercritical fluid into a material barrel, and thus the supercritical fluid and the fused material rapidly form a single system of the supercritical fluid and a polymer melt under the dual force fields; and the single system finally enters the moulding unit for foaming fixing. The plasticizing mixing speed is fast, and the mixing effect of the supercritical fluid and the polymer melt is good.

Description

technical field [0001] The invention relates to the technical field of continuous extrusion molding of microporous plastics, in particular to a supercritical fluid microporous plastic extrusion molding device and method. Background technique [0002] Microcellular plastic generally refers to a new type of foam plastic with a cell diameter of 0.1-10um and a cell density of 109-1015 cells / cm3, and the material density can be reduced by 5%-95% compared with that before foaming. In recent years, some supercritical fluids have become substitutes for traditional chemical fluids due to their unique advantages such as good solubility for most organic substances, low viscosity, large diffusion coefficient, non-toxic, non-flammable, no solvent residue, cheap and easy to obtain, safe to use, and no pollution to the environment. Ideal physical blowing agent for blowing agents. [0003] The basic process of supercritical fluid microporous plastic extrusion molding is: polymer pellets or...

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Problems solved by technology

In addition, most of the gas storage cylinders in most supercritical fluid gas injection devices are directly connected to the high-pressure plunger pump through the gas pipeline. The gas storage cylinder must be replaced when necessary, and there is still a large amount of residual gas in the gas storage cylinder that has not been fully utilized, which will inevitably cause unnecessary waste and increase production costs.

[0005] The traditional three-section screw includes three functional sections: the feeding section, the melting section and the metering section, and the exhaust screw mainly includes the feeding section, the first compression section, the first metering section, the exhaust section, the second compression section and the second metering section However, these two types of screws are not suitable for direct use in the extrusion and foaming of supercritical fluid microcellular plastics. The following problems generally exist: material accumulation is easy to occur at the dead corner of the supercritical fluid injection port of the barrel, and it is easy to Degradation or blockage of the inlet valve occurs; the length and diameter of the screw is relatively small, the material residence time is short, the supercritical fluid and the polymer melt are not mixed uniformly, and the pressure fluctuates greatly during the extrusion process; the metering section of the screw is short, and the machine head is established After the pressure, the flow of the molten material is too large, causing the gas injection port on the barrel to leak, etc.

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