EVOH Resin Composition for Weatherability Without Discoloration
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Solution Overview
Problem
Blending hindered amine-based and phenol-based compounds into ethylene-vinyl alcohol copolymer resins at high concentrations leads to discoloration, aggregate formation, and instability during extrusion, compromising weatherability and manufacturing stability in applications like agricultural films and geomembranes.
Innovation Solution
A resin composition combining ethylene-vinyl alcohol copolymer with a hindered amine-based compound having a 2,2,6,6-tetraalkylpiperidine ring structure and a hindered phenol-based compound with an ester or amide bond, at specific mass ratios, to enhance weatherability and manufacturing stability, while preventing discoloration and aggregate formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a hindered amine-based compound is blended into an ethylene-vinyl alcohol copolymer resin at a high concentration to maintain weatherability, then weatherability is improved, but discoloration of the resin occurs
Solution Approach 1:
The patent changes the concentration parameter of the hindered amine-based compound from high concentration to a controlled range (0.1-5 parts by mass per 100 parts of copolymer), and introduces a second compound (hindered phenol-based compound at 0.2-5 parts by mass) to create a synergistic effect that maintains weatherability while preventing discoloration
Solution Approach 2:
The patent creates a composite antioxidant system by combining a hindered amine-based compound and a hindered phenol-based compound in specific ratios, where the two compounds work together to provide both weatherability protection and color stability, eliminating the discoloration problem associated with using high concentrations of a single compound
2Reliability
If a hindered phenol-based compound is blended into an ethylene-vinyl alcohol copolymer resin at a high concentration to improve heat stability, then heat stability is improved, but aggregates are produced in the resin composition
Solution Approach 1:
The patent controls the concentration of the hindered phenol-based compound within a specific range (0.2-5 parts by mass per 100 parts of copolymer) and optimizes the ratio between the two compounds, preventing aggregate formation while maintaining heat stability through balanced composition
3Reliability
If an ethylene-vinyl alcohol copolymer resin composition containing hindered amine-based and hindered phenol-based compounds is manufactured through high-concentration blending, then weatherability effect is enhanced, but stability in extrusion deteriorates and manufacturing becomes unstable
Solution Approach 1:
The patent optimizes the concentration parameters of both compounds and their ratio to achieve a balance where sufficient weatherability protection is provided while maintaining extrusion stability and manufacturing consistency, avoiding the instability caused by high-concentration blending
Data Source
AI summary
A resin composition contains an ethylene-vinyl alcohol copolymer (A) in which an ethylene unit content is from 10 to 60 mol %, a hindered amine-based compound (B) having a 2,2,6,6-tetraalkylpiperidine ring structure and having an alkoxy group bonded to a nitrogen atom in the structure, and a hindered phenol-based compound (C) having an ester bond or an amide bond. The resin composition contains 0.1 to 5 parts by mass of the hindered amine-based compound (B) and 0.2 to 5 parts by mass of the hindered phenol-based compound (C) with respect to 100 parts by mass of the ethylene-vinyl alcohol copolymer (A), and a mass ratio (C)/(B) is from 0.2 to 3.6.