PEBA Copolymer Additive System for Low Yellowing Aging Resistance
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Solution Overview
Problem
Copolymers with polyamide and polyether blocks, used in materials like shoe soles, face issues with thermal and UV aging, as existing antioxidant and UV additives often cause unsightly yellowing, necessitating a specific combination of additives to maintain low yellow index and resistance.
Innovation Solution
A composition of PEBA copolymers with precise proportions of phenolic antioxidants, phosphorus-based or sulfur-based antioxidants, UV absorbers, and N-methylated hindered amine light stabilizers, which can be introduced during synthesis or post-processing, using a masterbatch technique to achieve balanced resistance and color stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If antioxidant and UV additives are added to improve resistance to thermal and UV aging, then the aging resistance is improved, but the yellow index increases causing unsightly yellowing
Solution Approach 1:
The patent applies parameter changes by precisely controlling the concentration ratios of different additives. Specifically, it uses phenolic antioxidant at 3000-8000 ppm, phosphorus/sulfur antioxidant at 1000-2000 ppm, UV absorber at 1000-2000 ppm, and N-methylated HALS at 300-2000 ppm. This specific parameter combination optimizes both aging resistance and color stability, resolving the contradiction between protection and yellowing.
Solution Approach 2:
The patent employs a composite additive system combining four types of stabilizers working synergistically. The phenolic antioxidant prevents oxidation, phosphorus/sulfur antioxidant provides secondary protection, UV absorber blocks紫外线, and N-methylated HALS offers additional UV protection with lower yellowing tendency. This composite approach achieves superior aging resistance while maintaining low yellow index compared to single or dual additive systems.
2Object-generated harmful factors
If N-methylated hindered amine light stabilizer is used to reduce yellowing, then the yellow index is reduced, but the UV resistance may be compromised without proper combination with other additives
Solution Approach 1:
The patent merges N-methylated HALS with UV absorbers and antioxidants in a unified stabilization system. The UV absorber (1000-2000 ppm) provides primary UV protection while N-methylated HALS (300-2000 ppm) provides secondary protection and radical scavenging. This combination maintains comprehensive UV resistance while the N-methylated HALS specifically reduces yellowing compared to conventional HALS.
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 specific additive combination effectively reduces yellowing and enhances thermal and UV resistance, maintaining a low yellow index while ensuring good UV resistance, as demonstrated by compositions M8, M10, and M11, which show improved stability over time.
Implementation Method 1
antioxidant and anti-UV additives are cited
Implementation Method 2
1000 to 2000 ppm of at least one UV absorber
Implementation Method 3
300 to 2,000 ppm of at least one N-methylated hindered amine or HALS type light stabilizer
Data Source
AI summary
A copolymer composition comprises homo- or copolyamide polyamide blocks and polyether blocks. The composition further comprises 500-10000 ppm of at least one phenolic antioxidant, 0-5000 ppm of at least one antioxidant based on phosphorus or based on sulfur, 0-5000 ppm of at least one UV absorber, 200-3000 ppm of at least one methylated hindered amine light stabilizer (HALS) and/or 200-1300 ppm of at least one nonmethylated HALS.