Resin Composition Impact Resistance via Intermediary Polymer

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Solution Overview

Problem

Saponified ethylene-vinyl ester copolymers exhibit poor impact resistance due to poor affinity with multilayer structure polymer particles, leading to cracking issues despite their excellent solvent resistance and gas barrier properties.

Innovation Solution

A resin composition comprising a saponified ethylene-vinyl ester copolymer, a rubber-like graft polymer, and a polyalkylene ether unit-containing polymer is developed, enhancing dispersibility and interface areas to improve impact resistance, with specific weight ratios and additives like glycidyl-group-containing (meth)acrylate polymer further optimizing properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If saponified ethylene-vinyl ester copolymer is used as packaging material, then gas barrier property and solvent resistance are improved, but impact resistance deteriorates due to cracking

Engineering Contradiction:
Improvegas barrier propertyVSAvoidimpact resistance
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The invention uses a composite resin composition comprising saponified ethylene-vinyl ester copolymer (A), rubber-like graft polymer (B), and polyalkylene ether unit-containing polymer (C). This composite structure combines the gas barrier properties of EVOH with the impact resistance of rubber particles and polyalkylene ether polymer, resolving the contradiction between reliability and strength.

Inventive Principle:
Principle #40Composite materials

2Strength

If multilayer structure polymer particles are blended in saponified ethylene-vinyl ester copolymer, then impact resistance is improved, but affinity between components is poor leading to limited effectiveness

Engineering Contradiction:
Improveimpact resistanceVSAvoidaffinity between components
Core Design Contradiction:
StrengthVSStability of the object's composition

Solution Approach 1:

The polyalkylene ether unit-containing polymer (C) acts as an intermediary component that enhances compatibility and affinity between the saponified ethylene-vinyl ester copolymer (A) and rubber-like graft polymer (B). This mediator improves the dispersion and interfacial adhesion, making the composite structure more effective.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention optimizes the compositional parameters by controlling the weight ratios of components (A), (B), and (C) within specific ranges. This parameter optimization ensures proper affinity and dispersion while achieving the desired impact resistance.

Inventive Principle:
Principle #35Parameter changes

3Strength

If rubber-like graft polymer is added to improve impact resistance, then dispersibility needs to be improved, but poor dispersibility limits impact absorbing efficiency

Engineering Contradiction:
Improveimpact resistanceVSAvoiddispersibility
Core Design Contradiction:
StrengthVSStability of the object's composition

Solution Approach 1:

The polyalkylene ether unit-containing polymer (C) serves as a dispersing agent and intermediary that enhances the dispersibility of rubber-like graft polymer (B) in the saponified ethylene-vinyl ester copolymer (A) matrix. This improved dispersibility increases the interfacial area and impact absorbing efficiency.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentUS8883920B2Resin composition and multilayer structural body employing the same
Publication Date: 2014.11.11 MITSUBISHI CHEM CORP

AI summary

The present invention provides a resin composition which comprises: (A) a saponifed ethylene-vinyl ester copolymer; (B) a rubber-like graft polymer; and (C) a polyalkylene ether unit-containing polymer. The inventive resin composition, which employs the saponfied ethylene-vinyl ester copolymer, is excellent in impact resistance.