酸化防止剤がポリマーの安定性をどのように改善するか
Why Polymers Degrade Through Oxidation
Polymer oxidation follows a chain reaction. Heat, UV radiation, mechanical shear, or metal contamination generates free radicals. These react with oxygen to form peroxy radicals, which continue the chain. Without antioxidants, this leads to yellowing, embrittlement, melt flow changes, and surface degradation.
Primary Antioxidants: Radical Scavengers
Hindered phenol antioxidants (酸化防止剤 1010, 1076, 1098) donate hydrogen atoms to peroxy radicals, converting them into stable molecules and breaking the chain reaction. They are the first line of defence against oxidative degradation.
Secondary Antioxidants: Hydroperoxide Decomposers
Secondary antioxidants address hydroperoxides — the key intermediates that reinitiate radical chains if left unchecked:
- Phosphites (酸化防止剤 168): Fast-acting at high melt temperatures, excellent processing stabilizers
- Thioesters (DSTDP, DLTDP): Cost-effective long-term thermal aging protection
Synergistic Systems
- 酸化防止剤 1010 + 168: Most widely used polyolefin system
- 酸化防止剤 1010 + DSTDP: Cost-effective long-term stabilization in PP/PE
- 酸化防止剤 1010 + 168 + ハルス: Full stabilization for outdoor applications
Polymer-Specific Selection
- PP: 1010 + 168 at 0.1–0.3% combined
- PE: Combined systems; confirm by OIT testing for pipe/geomembrane applications
- Engineering plastics: Grades stable at 250–300°C (酸化防止剤 168 is key at these temperatures)
よくある質問
Do antioxidants provide UV protection?
No. Antioxidants address thermal oxidative degradation only. For outdoor applications, UV absorbers and HALS stabilizers must be added separately.
Contact SUNCHEM
SUNCHEM's team can help recommend the right antioxidant system for your polymer and application. お問い合わせ for technical support and samples.