Coarse-pore EVA molded foaming material and preparation method thereof

Abstract

The invention relates to the field of plastic mold foaming, and provides a coarse-pore EVA molded foaming material for the problem of non-uniform pores of the coarse-pore EVA molded foaming material.The coarse-pore EVA molded foaming material is prepared from the following components in parts by mass: 10 to 20 parts of an ethylene-vinyl acetate copolymer, 55 to 78 parts of high pressure polyethylene, 5 to 10 parts of a high temperature foaming agent, 3 to 10 parts of a medium temperature foaming agent, 0.5 to 1 part of a crosslinker DCP, 0.5 to 1 part of zinc oxide, and 0.3 to 0.8 part of stearic acid. A preparation method of the coarse-pore EVA molded foaming material comprises the following steps: S1, performing mixing to form a mixture; S2, performing one-time opening; S3, performing secondary opening; and S4, performing foaming. By using the high temperature foaming agent and the medium temperature foaming agent, the melting point of the foaming agent is different from the meltingpoints of the ethylene-vinyl acetate copolymer and the high pressure polyethylene, so that the foaming agent is not easily decomposed in the mixing process, and coarse pores of the EVA molded foamingmaterial are more uniform and do not easily have chromatic aberration; and meanwhile, the tensile strength and the anti-seismic property of the EVA molded foaming material are not easily affected.

Description

technical field [0001] The invention relates to the field of plastic molding foaming, and more particularly, to a macroporous EVA molding foaming material and a preparation method thereof. Background technique [0002] Coarse-pored EVA molded foam material has good thermal insulation, heat insulation, sealing, shock resistance, chemical corrosion resistance and other properties, and is widely used in the packaging and transportation of precision instruments and in the fields that require high shock resistance. [0003] However, the existing macro-porous EVA molding foam materials usually use low-temperature foaming agent H and urea grease BK as foaming agents, because the melting point of low-temperature foaming agent H and urea grease BK is about 120 ° C, ethylene-vinyl acetate copolymerization The melting point of the material is about 80 °C, and the melting point of high-pressure polyethylene is about 110 °C. The melting point temperature difference between the foaming ag...

AI Technical Summary

Problems solved by technology

[0003] However, the existing coarse-cell EVA molded foam materials usually use low-temperature foaming agent H and urea fat BK as foaming agents. Since the melting points of low-temperature foaming agent H and urea fat BK are about 120°C, ethylene-vinyl acetate copolymerization The melting point of the compound is about 80°C, and the melting point of high-pressure polyethylene is about 110°C. The melting point temperature difference between the foaming agent and ethylene-vinyl acetate copolymer and high-pressure polyethylene is small. -Vinyl acetate copolymer and high-pressure polyethylene, the banburying temperature must reach at least the melting point of ethylene-vinyl acetate copolymer and high-pressure polyethylene, so that the banburying temperature is not easy to control, so that the foaming agent is easy to decompose in advance during the banburying process , and then it is easy to affect the foaming of the coarse-pore molded foam material, which makes the cell distribution of the prepared coarse-cell EVA molded foam material uneven, resulting in a large color difference of the coarse-cell EVA molded foam material, and even easily affects the thickness of the coarse-cell EVA foam. The tensile strength of the molded foam material weakens the shock resistance of the coarse-cell EVA molded foam material, so there is still room for improvement