A kind of coarse cell EVA molded foam material and preparation method thereof

Abstract

The invention relates to the field of plastic molded foaming. Aiming at the problem of uneven cells of the coarse-pored EVA molded foaming material, a coarse-pored EVA molded foaming material is provided, which comprises the following components in parts by mass: ethylene-vinyl acetate 10-20 parts of copolymer; 55-78 parts of high-pressure polyethylene; 5-10 parts of high-temperature foaming agent; 3-10 parts of medium-temperature foaming agent; 0.5-1 part of crosslinking agent DCP; 0.5-1 part of zinc oxide; 0.3-0.8 parts of stearic acid. A method for preparing a coarse-pore EVA molded foam material, comprising the following steps: S1, banburying to form a mixture; S2, first-time kneading; S3, second-time kneading; S4, foaming. By using high-temperature foaming agent and medium-temperature foaming agent, the melting points of the foaming agent and ethylene-vinyl acetate copolymer and high-pressure polyethylene are quite different, so that the foaming agent is not easy to decompose during the banburying process, making EVA molded The coarse-celled cells of the foam material are more uniform, less prone to color difference, and at the same time, the tensile strength and shock resistance of the EVA molded foam material are not easily affected.

Description

technical field [0001] The invention relates to the field of plastic molding foaming, more specifically, it relates to a coarse-pore EVA molding foaming material and a preparation method thereof. Background technique [0002] Coarse-cell 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 fields with high shock resistance requirements. [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 a...

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