Ethylene-vinyl alcohol copolymer composition, and shaped product and application thereof

Abstract

The invention provides an ethylene-vinyl alcohol copolymer of which the vinyl content is 25-50% and glass-transition temperature is 60-80 DEG C. The ethylene-vinyl alcohol copolymer has high-barrier effect and high strength and is good in processability. The invention also discloses shaped products, such as thin films, sheet materials, tube materials, injection molded products and the like, containing the ethylene-vinyl alcohol copolymer, and application of the shaped products to packaging, automobile fuel box, medical materials and textile materials, especially applications to barrier packaging.

Description

technical field [0001] The invention relates to the field of materials, more specifically to a polymer and its molded product and application. Background technique [0002] Ethylene-vinyl alcohol copolymer, polyvinylidene chloride and polyamide are known as the world's three major barrier resins. It is prepared by copolymerization and alcoholysis of ethylene and vinyl acetate. It is a new type of barrier material that combines the ease of processing of ethylene and the barrier properties of polyvinyl alcohol. It has good oil resistance, heat resistance, etc., and can effectively prevent the penetration of oxygen, carbon dioxide, nitrogen, helium and other gases. In addition, it also has excellent barrier properties to non-polar oils and organic solvents, which can prevent oil , The penetration of organic solvents, so the prospects for development and utilization are broad. However, there is a need to further increase the strength to reduce the thickness (weight) of packagi...

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Problems solved by technology

For example: Chinese patent 201810671474.7 prepares a composite film by blending montmorillonite and ethylene-vinyl alcohol copolymer and filling chitosan nanofibers at the same time, which improves the mechanical properties and barrier properties, but its preparation method is complicated and costly

Chinese patent 201110189511.9 is modified by adding calcium sulfate, corn starch and other additives to the ethylene-vinyl alcohol copolymer. Although the obtained composite material has good mechanical properties, low manufacturing cost and is easy to degrade, the small molecule additives The addition of ethylene-vinyl alcohol copolymer will destroy the regularity of the ethylene-vinyl alcohol copolymer, which will cause a loss of barrier properties

Chinese patent 200910214042.4 improves the toughness by blending high-density polyethylene and ethylene-vinyl alcohol copolymer. The toughness at room temperature and low temperature is obviously improved, but the barrier property is basically not improved.

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