Functions of Acid‑alkali‑resistant Coating for Warp‑Knitted PET Geogrid
Functions of Acid‑alkali‑resistant Coating for Warp‑Knitted PET Geogrid
Although PET substrate has inherent moderate chemical stability, long‑term exposure under saline‑alkali soil, landfill leachate and mine‑acidic‑water will trigger gradual hydrolysis and strength degradation. The acid‑alkali‑resistant coating is a modified PVC protective layer wrapped around every PET filament.
Core Functions
1. Isolate corrosive media and protect PET filaments
Saline‑alkali underground water, landfill leachate and mine‑acid‑liquids erode polyester yarns and cause fibre hydrolysis and brittle fracture. The coating separates corrosive agents from PET substrate and preserves long‑term tensile capacity.
2. Improve anti‑ageing performance (anti‑hydrolysis & anti‑oxidation)
Persistent damp‑soil moisture plus acid‑alkali accelerates PET hydrolysis. Stabilisers and antioxidants are added into modified coating formulation to retard material ageing and extend service life.
3. Enhance junction strength
Junction points are stress‑vulnerable zones of warp‑knitted geogrid. The coating bonds interlaced yarns firmly together, improving junction peeling‑and‑tearing resistance and guaranteeing overall reinforcement performance under load.
4. Increase interfacial friction‑interlock with backfill soil
Proper surface roughness of coated geogrid elevates friction coefficient between geogrid and granular fill, giving full play to soil‑geogrid interlocking and improving overall soil‑mass stability.
5. Resist microbial degradation
Microbes exist in landfill sites and silty soils. The coating protects polymer substrate against micro‑biological decomposition and premature failure.
Mandatory Application Scenarios for Acid‑alkali‑resistant‑coated Grade
- Saline‑alkali subgrade and coastal soft‑soil projects
- Municipal and hazardous‑waste landfill slope‑and‑liner‑systems
- Mine tailings ponds and acid‑mine‑residue stockpiles
- Backfill for chemical‑industry contaminated‑site remediation
Supplementary Notes
- Uncoated bare‑filament warp‑knitted PET geogrid is only allowed for permanently‑buried neutral‑dry‑soil conditions, not for corrosive saline‑alkali environments.
- Distinction: general‑purpose PVC coating ≠ modified acid‑alkali‑resistant PVC coating. Conventional PVC provides simple physical wrapping with limited chemical‑resistance. Special corrosion‑resistant additives are incorporated for aggressive‑environment‑grade coating.
