Multi-Layer Structure and Method of Producing the Same

Abstract

A multi-layer structure comprising a functional resin layer obtained by covering a core layer of a base body resin or a second functional resin with a shell layer of a first functional resin, and a base body resin layer containing the functional resin layer therein. The layers of the functional resins are formed at positions where they are allowed to exhibit their functions to a sufficient degree, a plurality of functions can be imparted, and a molten resin mass having the above multi-layer structure can be formed by the compression-forming.

Description

TECHNICAL FIELD [0001] The present invention relates to a multi-layer structure having a base body resin layer of a thermoplastic resin and a functional resin layer of a functional resin. More specifically, the invention relates to a multi-layer structure having a layer structure in which functional resins such as a barrier resin and an oxygen-absorbing resin are allowed to efficiently exhibit their functions, and to a method of producing the same. BACKGROUND ART [0002] In the field of packaging containers, there have been used a variety of resins and resin compositions capable of exhibiting such functions as heat resistance, barrier property, oxygen-absorbing property and the like properties. These functional resins are used in combination with a base body resin which chiefly works to maintain the formability of the structure. [0003] As the functional resins, there have been known gas-barrier resins such as ethylene / vinyl alcohol copolymers, and oxygen-absorbing resin compositions ...

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Benefits of technology

[0008] It has also been attempted to combine a plurality of layers of the functional resins to enhance the effect encountering, however, the difficulty in efficiently forming the layers by the compression-forming.

[0025] According to the method of producing a multi-layer structure of the invention, further, there can be efficiently formed by compression-forming a multi-layer structure permitting the layers of the functional resins to be formed at positions where they exhibit their functions to a sufficient degree, and having a multiplicity of functions.

Problems solved by technology

In the multi-layer structure bodies such as container closures and containers having a multi-layer structure of functional resins and other resin such as a base body resin, however, it is difficult to place the layers of the functional resins at positions where excellent functions possessed by the functional resins can be exhibited to a sufficient degree.

When the functional resin which is an oxygen-absorbing resin is covered for its surfaces with a thick base body resin, however, oxygen that is to be absorbed is prevented from efficiently arriving at the layer of the oxygen-absorbing resin, making it difficult to efficiently exhibit oxygen-absorbing property.

On the other hand, if the amount of the functional resin is increased so as to exist up to near the surface of the structure, a problem arouses concerning the cost and, besides, deteriorating the mechanical strength and the formability.

It has also been attempted to combine a plurality of layers of the functional resins to enhance the effect encountering, however, the difficulty in efficiently forming the layers by the compression-forming.

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