High Temperature & Humidity Aging Test and Selection Specification For Halogen-free Flame-retardant PA66 Plastic Fasteners, Based On IEC 61249
High Temperature & Humidity Aging Test and Selection Specification For Halogen-free Flame-retardant PA66 plastic fasteners, Based On IEC 61249
Halogen-free flame-retardant plastic clips and standoffs are widely used inside energy storage and DC charging piles. Long-term high temperature and high humidity cause shrinkage, brittle crack and degraded flame resistance, bringing fire hazards. This article unifies aging test and selection standards complying with IEC 61249 and UL94.
1. Working Condition Matching Of Three Flame Retardant Grades
| Flame Retardant Grade | Halogen-free Compliance | Status After 500h 85℃ Damp Heat Aging | Applicable Scenario |
| UL94 HB | Optional halogen-free | Slight shrinkage, obvious flame retardancy decline | Low-voltage normal temperature control cabinet wiring |
| UL94 V1 | Halogen-free available | Stable dimension, self-extinguish without molten drop | General AC charging pile low-voltage area |
| UL94 V0 | Dedicated halogen-free formula | No shrinkage & crack, stable flame retardancy | Energy storage PACK, high-voltage DC charging pile interior |
2. Standard Damp Heat Aging Test Procedure
1. Sample pre-treatment: Keep finished parts at room temperature for 24h, record original size, impact strength and combustion grade; 2. Accelerated aging: 500h continuous storage in 85℃, 85RH constant temperature & humidity chamber; 3. Retest judgment: Cool samples to room temperature and recheck dimension change, impact strength and flame performance for energy storage high-voltage application approval.
3. Rectification For High-temperature Brittle Crack Failure
1. Material upgrade: Replace HB grade with modified V0 halogen-free glass fiber PA66 with hydrolysis resistant additives; 2. Structure optimization: Add fillet transition at clip root to eliminate stress concentration; 3. Assembly control: Reserve 0.1~0.2mm harness gap to release thermal expansion stress, forced clamping forbidden.