EVOH Resin Composition Impact Resistance Gas Barrier
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Solution Overview
Problem
Ethylene-vinyl alcohol copolymer (EVOH) resin compositions face challenges in achieving high impact resistance and adhesive strength while maintaining gas barrier properties, as they tend to be brittle due to high crystallinity, and blending with other resins reduces the EVOH ratio and gas barrier properties.
Innovation Solution
An EVOH resin composition is developed using EVOH in combination with acetic acid and/or its salt, an aliphatic carboxylic acid, and a metal salt of the aliphatic carboxylic acid from long Periodic Table 4th-period d-block elements, along with boric acid, to enhance impact resistance, adhesive strength, and color tone stability without blending with other resins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If EVOH is blended with other resins to improve impact resistance, then impact resistance is improved, but the EVOH ratio reduces and gas barrier property deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters by introducing acetic acid, aliphatic carboxylic acid, and their metal salts into the EVOH system. This modifies the molecular interactions and crystallinity parameters of EVOH, improving impact resistance while maintaining the high EVOH content (90-100%) necessary for gas barrier properties.
Solution Approach 2:
The patent uses acetic acid, aliphatic carboxylic acid, and their metal salts as intermediary substances that mediate between the conflicting requirements. These intermediaries modify the EVOH molecular chains to reduce brittleness without requiring blending with other resins, thus preserving gas barrier properties while improving impact resistance.
2Reliability
If EVOH content is increased to maintain gas barrier property, then gas barrier property is maintained, but impact resistance deteriorates due to high crystallinity and brittleness
Solution Approach 1:
The patent changes the physical and chemical parameters of EVOH by adding acetic acid, aliphatic carboxylic acid, and their metal salts. These parameter changes reduce the excessive crystallinity and brittleness of high-EVOH content compositions, enabling impact resistance improvement while maintaining high EVOH content for gas barrier properties.
Solution Approach 2:
The acetic acid, aliphatic carboxylic acid, and their metal salts act as intermediaries that modify the molecular structure of EVOH. They reduce intermolecular hydrogen bonding density to decrease crystallinity and brittleness, allowing high EVOH content to be maintained without sacrificing impact resistance.
3Strength
If fatty acid metal salt is added to improve impact resistance, then impact resistance is improved, but thermal decomposition is accelerated and color tone deteriorates
Solution Approach 1:
The patent changes the type of metal salt from general fatty acid metal salts to specific metal salts where the metal is at least one of Li, Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, or Ba. This parameter change in metal species selection improves impact resistance while avoiding the thermal decomposition and coloration problems associated with other fatty acid metal salts.
Solution Approach 2:
The patent uses small amounts of acetic acid, aliphatic carboxylic acid, and their metal salts as sacrificial additives that perform their function of improving impact resistance and preventing thermal decomposition, then can be consumed or decomposed without affecting the overall performance of the EVOH composition.
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 composition achieves improved impact resistance, adhesive strength, and color tone stability, maintaining excellent gas barrier properties and preventing thermal decomposition, even at elevated temperatures.
Implementation Method 1
the EVOH has an ample amount of hydroxy groups in the molecular chain, and hence has a high crystallinity. Accordingly, the EVOH tends to be brittle
Implementation Method 2
hydroxy groups abundantly present in a molecular chain of the EVOH are strongly hydrogen-bonded to form a crystal portion, and the crystal portion prevents the penetration of oxygen from the outside
Implementation Method 3
it has been generally known that a fatty acid metal salt accelerates the thermal decomposition of the EVOH to reduce the impact resistance and color tone
Data Source
AI summary
An ethylene-vinyl alcohol copolymer resin composition, including: an ethylene-vinyl alcohol copolymer (A); acetic acid and/or a salt thereof (B) ; an aliphatic carboxylic acid (C) other than acetic acid; and an aliphatic carboxylic acid metal salt (D) , wherein a metal species of the salt (D) is at least one selected from long Periodic Table 4th-period d-block elements, and wherein respective contents of the acetic acid and/or the salt thereof (B) , the acid (C), and the salt (D) satisfy the following formulae (1) and (2) on a weight basis is provided. The resin composition is excellent in impact resistance and adhesive strength even without being blended with any other resin: 0.001≤contentofDintermsofmetalion/contentofBintermsofaceticacidion≤1.30 0.11≤contentofDintermsofmetalion/contentofCintermsofcarboxylicacidion≤100