Multilayer container

Abstract

The multilayer container of the present invention comprises an outermost layer, an innermost layer and at least one intermediate layer interposed between the outermost layer and the innermost layer. Each of the outermost and innermost layers is mainly made of a thermoplastic polyester resin A produced by polymerizing a dicarboxylic acid component comprising 80 mol% or higher of terephthalic acid with a diol component comprising 80 mol% or higher of ethylene glycol. At least one of the intermediate layers is mainly made of a mixed resin B of a polyamide resin C and a polyamide resin D in a mixing ratio of 99.5 / 0.5 to 80 / 20 by weight. The polyamide resin C is produced by polymerizing a diamine component comprising 70 mol% or higher of m-xylylenediamine with a dicarboxylic acid component comprising 70 mol% or higher of adipic acid. The polyamide resin D has a solubility index satisfying the formula (1): <DF NUM=''(1)''>Sa < Sd < Sc < / DF> wherein each of Sa, Sb and Sd is a solubility index, calculated by Small method, of the thermoplastic polyester resin A, the polyamide resin C and the polyamide resin D. The polyamide resin D has a glass transition temperature of 130 DEG C or lower which is higher than that of the polyamide resin C. The multilayer container is excellent in gas-barrier property and resistant to delamination even when its shape includes indented and bending portions, allowing a broad design latitude.

Description

multilayer container technical field The present invention relates to the prevention of delamination between layers of multi-layer containers, in particular, when the multi-layer container is transported or dropped and impacted, the interlayer adhesion between the innermost layer and the outermost layer and the middle layer is improved, and multiple layers can be prevented. The delamination of the layered container can avoid the delamination even if it is not a shape with few concave-convex parts and bending parts, and the multi-layer container has a large degree of design freedom. Background technique Currently, plastic containers (bottles, etc.) mainly made of polyester such as polyethylene terephthalate (PET) are widely used for tea, juice drinks, carbonated drinks, and the like. In addition, among plastic containers, the proportion of small plastic bottles is increasing year by year. As the size of the bottle increases, the ratio of the surface area per unit volume in...

AI Technical Summary

Problems solved by technology

As a method of improving these problems, the following is disclosed: when the resin constituting the innermost layer and the outermost layer is finally injected into the cavity of the mold, a counterflow regulating device that can make a certain amount of backflow on the side of the gas barrier layer is used to make the coarse mixing Resin is interposed between layers to improve delamination resistance, but there is a problem of using a special device (JP-A-2000-254963)