Foam-Molded Container Stopper With Oxygen Barrier

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Solution Overview

Problem

Existing synthetic resin stoppers have insufficient oxygen gas barrier properties, which limits their effectiveness in preventing gas permeation and maintaining the integrity of contents in containers.

Innovation Solution

A container stopper is developed using a foam-molded article with a specific expansion ratio, obtained by foaming a thermoplastic elastomer composition containing a hydrogenated block copolymer, a softening agent, and a polyolefin resin, with a foaming agent added in a controlled amount to enhance uniformity of foam cell size and improve oxygen gas barrier properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a synthetic resin stopper is used to replace natural cork, then problems such as corky odor and bacterial contamination are solved, but oxygen gas barrier property is insufficient

Engineering Contradiction:
Improvecorky odor and bacterial contaminationVSAvoidoxygen gas barrier property
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent uses a composite material system consisting of a hydrogenated block copolymer (containing aromatic vinyl compound blocks and conjugated diene blocks), a polyolefin resin, and a foaming agent. This composite structure combines the gas barrier properties of the hydrogenated block copolymer with the sealing and elasticity characteristics of the polyolefin resin, achieving both the elimination of cork defects and improved oxygen barrier performance.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent employs a foamed material structure with controlled cell morphology. The foaming agent creates a porous network that provides both the desired elasticity and compression properties for stopper function, while the hydrogenated block copolymer matrix maintains effective gas barrier properties by controlling the continuous phase composition and reducing gas permeation pathways through the foam structure.

Inventive Principle:
Principle #31Porous materials

2Strength

If a foamed material is used in the stopper, then elasticity and sealing property are improved, but oxygen gas barrier property becomes insufficient

Engineering Contradiction:
Improveelasticity and sealing propertyVSAvoidoxygen gas barrier property
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent optimizes specific parameters including the molecular weight and microstructure of the hydrogenated block copolymer (controlling the glassy block and elastic block characteristics), the ratio of polyolefin resin to hydrogenated block copolymer, and the foaming agent content and type. These parameter adjustments ensure that the foamed structure provides adequate elasticity and sealing while maintaining oxygen barrier properties through controlled cell size, distribution, and wall thickness.

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The container stopper achieves excellent oxygen gas barrier properties and pull-out performance, ensuring the integrity and freshness of contents by maintaining a controlled expansion ratio and uniform foam cell structure.

Implementation Method 1

a chemical foaming agent having a decomposition temperature of 160° C. or less

Methodology Applied
Scientific EffectDecomposition: Decomposition (biological)

Implementation Method 2

a hydrogenated block copolymer obtained by hydrogenating a block copolymer having one or more polymer block A mainly containing an aromatic vinyl compound and one or more polymer block B mainly containing a conjugated diene compound

Methodology Applied
Scientific EffectHydrogenation: Hydrogenation

Data Source

PatentUS8973781B2Container stopper comprising foam-molded article
Publication Date: 2015.03.10 KURARAY CO LTD

AI summary

Provided is a container stopper containing a foam-molded article which has an expansion ratio of 1.1 to 2.5 times and is obtained by foaming a mixture containing: a thermoplastic elastomer composition containing 100 parts by mass of (a) a hydrogenated block copolymer containing (A) a polymer block containing a structural unit derived from an aromatic vinyl compound and (B) a polymer block containing a structural unit derived from isoprene or a mixture of isoprene and butadiene, 5 to 150 parts by mass of (b) a softening agent, and from 5 to 150 parts by mass of (c) a polyolefin resin; and (d) 0.1 to 3% by mass of a foaming agent.