Method for preparing extruding physical foaming polypropylene bead granule

Abstract

The invention discloses a preparation method of an extrusion physical foaming polypropylene bead; the method is as follows: an injector port is arranged at the middle of a machine barrel of a screw extruder, a machine head is provided with a bushing type neck ring mold and a die surface chip cutter, polypropylene foaming material and addition agents are added into the screw extruder, alkane foaming agent is injected into the machine barrel from the injector port, the proportion by weight between the polypropylene foaming material and the alkane foaming agent is 10-25%, the pressure of the neck ring mold is controlled to be 5-30MPa, and the temperature of the neck ring mold is 110-150 DEG C, thus leading the cut material to generate foams when the material enters the atmosphere, and then the product is obtained after cooling and drying. The method of the invention has the advantages of continuous extrusion of the polypropylene foaming beads, low energy consumption, little environmentalpollution due to the adoption of the alkane foaming agent, low residue of foaming agent in the foaming bead and high foaming rate.

Description

A kind of preparation method of extruding physically expanded polypropylene beads technical field The invention relates to a production process for extruding foamed polypropylene beads, which belongs to the field of polymer foaming materials. Background technique In addition to the characteristics of general foaming products such as light weight, heat insulation, sound insulation, cushioning and shock resistance, high specific strength, and low price, foamed polypropylene plastics also have good thermal stability (the maximum use temperature is 120°C, while foaming Polystyrene and polyethylene are only 70 ℃ ~ 80 ℃), good stress cracking resistance (this performance is necessary for greasy food packaging) and dimensional stability of products at high temperatures, high toughness and high Tensile strength and impact strength, conformable and supple surface, excellent microwave adaptability. Moreover, due to the existence of a methyl group on the polypropylene molecule, its ...

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Problems solved by technology

The disadvantage of this method is that random copolymerized polypropylene with low melting point is used, and the obtained product has a low melting point, which is not suitable for use in high temperature places.