Method for recovery and granulation of high performance glass fiber reinforced liquid crystalline polymer secondary material

Abstract

The invention discloses a method for recovery and granulation of a high performance glass fiber reinforced liquid crystalline polymer secondary material. The method comprises the following steps: fragmenting a secondary material produced during injection molding of a glass fiber reinforced liquid crystalline polymer material and unqualified components; then removing metal filings probably mixed into the secondary material to be recovered through sieving with a metal separator; carrying out extrusion molding by using a single-screw extruder with an appropriate length-diameter ratio, wherein processing temperature is 325 to 380 DEG C; conveying braces by using a metal chain; and carrying out pelletizing after the braces are cooled to some extent so as to obtain a glass fiber reinforced liquid crystalline polymer granulation material with uniform particles. According to the method, since the shearing action of the single-screw extruder is weak, the secondary material to be recovered only suffers weak shearing during the process of plasticizing; thus, long length of glass fibers can be maintained, and damage to liquid crystalline polymer chain segments can be reduced; and compared to traditional methods, the method provided by the invention is advantaged in that the prepared granulation material has good mechanical behaviors and heat resistance and can be individually applied to electronic products needing reflow soldering at a temperature of 260 DEG C.

Description

technical field [0001] The invention relates to the processing technology of high-temperature-resistant engineering plastics, in particular to a method for recycling and granulating secondary materials of high-performance glass fiber reinforced liquid crystal polymers. Background technique [0002] Liquid crystal polyester is a thermotropic main chain liquid crystal polymer (TLCP, thermotropie main-ehainliquide–stalpolyester), which has the characteristics of low melt viscosity, easy molding, high strength, heat resistance, chemical resistance, good shielding property, etc. The thermotropic liquid crystal polymer was first researched and developed after the Eastman Kodak Company of the United States discovered that ethylene terephthalate (PET) modified p-hydroxybenzoic acid (PHB / PET) displayed thermotropic liquid crystals in 1976. A series of copolyesters was developed called Xydar and commercialized by Darteo in 1984. In 1985, Japan's Sumitomo Corporation developed Ekonol ...

AI Technical Summary

Problems solved by technology

[0005] Compared with conventional plastics, glass fiber-reinforced liquid crystal polymers have the characteristics of high temperature resistance, good fluidity and high hardness. For the development of the current industrial level, the recycling method of TLCP secondary materials is mainly the twin-screw extrusion method, although This method has the advantages of high production efficiency and uniform and dense particles. However, due to the strong shearing of the TLCP secondary material during the twin-screw extrusion process, the length of the glass fiber will decrease and the segment of the liquid crystal polymer will be cut. The overall mechanical properties of the glass fiber reinforced liquid crystal polymer granules obtained by this method decrease by more than 30%, and the heat-resistant temperature drops by more than 15°C, which seriously affects the use of glass fiber reinforced liquid crystal polymer granules.

In addition, due to the large amount of twin-screw extrusion, once the material flows unevenly, it is easy to cause melt fracture at the die mouth of the machine head and cannot be extruded normally, and it will accumulate into a block of glass fiber reinforced LCP material, which cannot be used.

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