EVOH Resin Composition with Cinnamic Acid UV Absorbers

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Solution Overview

Problem

Conventional packaging materials with ultraviolet absorbers face issues such as bleeding, reduced ultraviolet absorbing effect, and odor generation when used for long periods, especially with contents containing alcohol, and they fail to provide adequate barrier properties against oxygen and carbon dioxide.

Innovation Solution

A resin composition incorporating saponified ethylene-vinyl ester-based copolymer (EVOH) with cinnamic acids and either an alkali metal salt or an alkaline earth metal salt, which absorbs specific ultraviolet wavelengths without reducing the ultraviolet absorbing effect and prevents odor generation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a water-soluble ultraviolet absorber is incorporated into a polyvinyl alcohol film to achieve transparency and prevent light degradation, then the ultraviolet absorbing effect is improved, but the absorber bleeds out over time causing deterioration of appearance, reduction in ultraviolet absorbing effect, and generation of odor

Engineering Contradiction:

Improveultraviolet ray transmissionVSAvoidstability of ultraviolet absorbing effect

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent changes the chemical parameters of the ultraviolet absorber by using cinnamic acid and its derivatives with specific molecular structures and properties. These parameter changes result in an absorber that is incorporated into the EVOH film and does not bleed out, maintaining stable ultraviolet absorption over time while preventing odor generation.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite material system by combining EVOH (saponified ethylene-vinyl ester copolymer) with cinnamic acid-based ultraviolet absorbers. This composite structure ensures the absorber is integrated within the film matrix, preventing bleeding while maintaining transparency and ultraviolet absorption effectiveness.

Inventive Principle:

Principle #40Composite materials

2Object-affected harmful factors

If conventional ultraviolet absorbers are used in packaging materials, then light degradation of contents is prevented, but odor generation occurs especially when contents contain alcohol

Engineering Contradiction:

Improvelight degradationVSAvoidodor generation

Core Design Contradiction:

Object-affected harmful factorsVSObject-generated harmful factors

Solution Approach 1:

The patent modifies the chemical parameters of the ultraviolet absorber by selecting cinnamic acid and its derivatives with specific molecular characteristics. These parameter changes result in an absorber that does not react with alcohol-containing contents to generate odor, while still effectively preventing light degradation.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses a stable, non-reactive ultraviolet absorber that maintains its properties throughout the packaging material's lifecycle, eliminating the need for frequent replacement due to odor generation or effectiveness loss.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Reliability

If polyvinylidene chloride-based polymer is used for gas barrier properties, then oxygen barrier property is improved, but harmful chlorine compounds are generated during incineration disposal

Engineering Contradiction:

Improveoxygen barrier propertyVSAvoidchlorine compound generation

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent changes the chemical composition parameter of the gas barrier layer by using EVOH (saponified ethylene-vinyl ester copolymer) instead of polyvinylidene chloride-based polymer. This parameter change eliminates chlorine content in the material, preventing harmful chlorine compound generation during disposal, while maintaining effective oxygen barrier properties.

Inventive Principle:

Principle #35Parameter changes

4Reliability

If metal layers are used for gas barrier properties, then oxygen barrier property is improved, but packaged contents become invisible and disposability is poor

Engineering Contradiction:

Improveoxygen barrier propertyVSAvoidtransparency and disposability

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent changes the material parameter of the gas barrier layer from metal-based to polymer-based (EVOH). This parameter change maintains the oxygen barrier function while improving transparency to keep contents visible and enhancing disposability by eliminating metal recovery requirements.

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 resin composition effectively absorbs UV-B or UV-C light below 320 nm, maintaining the ultraviolet absorbing effect and preventing odor issues, while providing improved oxygen and carbon dioxide barrier properties.

Implementation Method 1

incorporating a water-soluble ultraviolet absorber into a film made of a resin such as polyvinyl alcohol

Methodology Applied

Scientific EffectUltraviolet absorption: Absorption (EM radiation)

Data Source

PatentUS10961370B2Resin composition, melt-molded article using same, and multilayered structure

Publication Date: 2021.03.30 MITSUBISHI CHEM CORP

AI summary

The present invention relates to a resin composition containing a saponified ethylene-vinyl ester-based copolymer (A), cinnamic acids (B), and at least either one (C) of an alkali metal salt (C1) and an alkaline earth metal salt (C2) (provided that the component (C) excludes a salt of cinnamic acid), a melt-molded article using the composition, and a multilayer structure.