Preparation method of chemically-crosslinking-foamed polyethylene material, and screw rod

Abstract

The invention provides a preparation method of a chemically-crosslinking-foamed polyethylene material, and a screw rod. The preparation method includes: uniformly mixing components of the polyethylenematerial formula and extruding the mixture via a single screw extruder. The polyethylene material includes, by mass, 40-60 parts of LDPE, 20-40 parts of HDPE, 10-20 parts of EVA, 2-5 parts of azodicarbonamide, 0.5-2 parts of dicumyl peroxide, 2-4 parts of ZnO, and 1-2 parts of zinc stearate. The screw rod in the single screw extruder includes a screw working section, which includes, in a successively connected manner in the transporting direction of materials, a first forward screw transportation section, a reverse screw transportation section, a second forward screw transportation section, areverse kneading section, a mixing section, and a third forward screw transportation section. The method can achieve production of the chemically-crosslinking-foamed polyethylene in the single screwextruder by means of extrusion therewith, thus achieving continuous production and improving production efficiency.

Description

technical field [0001] The invention relates to the technical field of polyethylene foam preparation, in particular to a preparation method for producing chemically cross-linked foamed polyethylene material through single-screw extrusion, and also relates to a screw of a single-screw extruder. Background technique [0002] Polyethylene (PE) foam has excellent physical, chemical and mechanical properties. Its foamed products are light in weight, corrosion-resistant, heat-insulating, insulating, and have certain toughness. They can be processed mechanically such as nails and saws, and are widely used. In chemical industry, construction and other fields. The molding process of PE foam is divided into chemical foaming method and physical foaming method. The physical foaming method requires special equipment for transporting the physical foaming agent, or adds a very cumbersome process, and the preparation cost is relatively high. [0003] The chemical foaming method is divided...

AI Technical Summary

Problems solved by technology

The physical foaming method requires special equipment for transporting the physical foaming agent, or adds a very cumbersome process, and the preparation cost is high

[0003] The chemical foaming method is divided into chemical cross-linking and radiation cross-linking, and radiation cross-linking also requires very expensive irradiation equipment and a large investment.

Since polyethylene is a highly crystalline polymer, it has high viscoelasticity at the melting point. When it is close to the melting point (around 130°C), the melting point will drop sharply, and the melt strength will also decrease accordingly; polyethylene is cross-linked first, which is suitable for foaming The temperature is very narrow, the process is difficult to control, and it is difficult to achieve stable foaming production when extruding through a single-screw extruder

Therefore, the current production of PE foam products by chemical crosslinking is mostly produced by molding method, but its production is discontinuous, and the application of products is greatly limited.

The use of single-screw extruders to prepare PE foaming materials is currently mainly found in physical foaming methods; when PE is melted in the extruder, the foamable gas needs to be injected into the PE solution through special production equipment. Foaming; currently there are two main processes, one is foaming with butane, but butane itself is flammable, explosive and toxic, which is relatively dangerous; the other is foaming with carbon dioxide, but the required equipment is expensive, and every The investment of a production line exceeds 10 million yuan

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