TGIC Polyester Powder Coat Resin Technical Material Specification
Comprehensive technical specification for TGIC (Triglycidyl Isocyanurate) cross-linked polyester powder coating resin, covering Canadian industrial finishing applications, standard particle sizing, cure schedules, film properties, defect modes, and storage guidelines for fabrication and coating shops.
Material Overview & Common Uses
TGIC Polyester Powder Coat Resin is a thermosetting powder coating system where the polyester resin is cross-linked with Triglycidyl Isocyanurate (TGIC). This chemistry provides exceptional exterior durability, UV resistance, and mechanical toughness, making it the standard for architectural aluminum extrusions, outdoor furniture, automotive wheels, agricultural equipment, and heavy machinery in Canadian climates. The powder is applied electrostatically and cured by heat, forming a hard, glossy, or textured finish that withstands abrasion, corrosion, and weathering. TGIC systems are widely specified in Canada for AAMA 2604 and 2605 performance requirements.
Core Technical Properties & Sizing
| Parameter | Value |
|---|---|
| Chemistry | Polyester resin cross-linked with TGIC – typically 90-93% polyester, 7-10% TGIC by weight |
| Particle Size Distribution (PSD) | D50 = 25–35 µm; D10 ≥ 5 µm, D90 ≤ 70 µm; oversized >100 µm <1% by mass |
| Specific Gravity | 1.2–1.6 g/cm³ (typical white ~1.4) |
| Cure Schedule | Standard: 10 min @ 200°C (metal temp); low-bake: 15 min @ 180°C; peak hold ±5°C |
| Gel Time | 60–120 seconds @ 200°C (ISO 8130-6) |
| Theoretical Coverage | 10–12 m²/kg at 60 µm (100% transfer efficiency; actual yield 60-75%) |
| Film Thickness Range | 50–120 µm (typical arch. spec 60–80 µm) |
| Gloss Levels (60°) | 5–95% (standard 70-85%; matte 20-30%) |
| Impact Resistance | Direct >80 in·lb; reverse >60 in·lb (ASTM D2794, 60 µm on 0.032" Al) |
| Pencil Hardness | 2H–4H (ASTM D3363) |
| MEK Resistance | >100 double rubs, no softening (ASTM D5402) |
| Salt Spray Resistance | >1000 hours, <1 mm creep (ASTM B117, chromated Al) |
| QUV Resistance | >500 hours, <50% gloss retention loss (ASTM G154 UVA-340) |
| Storage Stability | 12 months from mfg when stored <25°C and <60% RH |
Machinability, Tooling & Feeds
| Parameter | Value |
|---|---|
| Application Method | Electrostatic spray (corona or tribo) |
| Gun Voltage (Corona) | 60–90 kV |
| Powder Flow Rate | 200–600 g/min |
| Atomizing Air Pressure | 1.5–3.0 bar |
| Pattern Air Pressure | 0.5–1.5 bar |
| Part Grounding Resistance | <1 MΩ |
| Gun Distance | 150–300 mm |
| Conveyor Speed | 3–5 m/min |
| Cure Oven Zones (Standard) | Preheat 180°C, Hold 200°C ±5°C, Cool-down |
| Low-Bake Cure Temp / Time | 180°C / 15 min dwell |
| Reclaim Max Ratio | 30% virgin blend, sieved through 100-mesh |
| Moisture Avoidance | Discard or dry powder if exposed to >60% RH for >4 hrs (dry at 30°C / 24h) |
Common Defects & Quality Control
| Defect | Description | Corrective Action |
|---|---|---|
| Orange peel | Caused by high film thickness, incorrect particle size, or insufficient flow time | Reduce film build to 60–80 µm or adjust cure temperature ramp |
| Pinholes / outgassing | From moisture in substrate or powder | Preheat substrate to 120°C for 5 min; store powder below 25°C / 60% RH |
| Poor adhesion | Inadequate pretreatment (cleanliness, conversion coating) | Verify chromate or zirconium pretreatment per ASTM B117 |
| Gloss variation | Inconsistent cure temperature or reclaim ratio | Monitor oven profile with data loggers; limit reclaim to 30% |
| Contamination | Dirt, oil, or silicone from compressed air | Install coalescing filters; check air quality weekly |
| Back-ionization | Excessive voltage or powder flow | Reduce gun voltage to 60 kV or increase gun distance |
QC checks per batch: film thickness (elcometer), gloss (60° glossmeter), MEK rubs (100 double rubs), crosshatch adhesion (ASTM D3359). Salt spray and QUV per project spec.
Storage, Handling & Racking Guidelines
Store powder in original sealed containers in a climate-controlled room at 15–25°C and <60% relative humidity. Avoid direct sunlight and temperature fluctuations. Stack containers on pallet racking with max 3-high to prevent compaction. Use FIFO rotation; label each container with date of manufacture and lot number. Do not store near ovens, compressors, or exterior doors. For active use, keep hopper and reclaim systems sealed; clean all hoses and guns daily to prevent cross-contamination. Racking for coated parts: use aluminum or steel hooks with PTFE or silicone tips to avoid marring; maintain minimum 50 mm spacing between parts for airflow. Cured parts can be stacked after 24-hour cool-down; use protective interleaving (kraft paper or foam) for high-gloss finishes. Dispose of expired or contaminated powder per local hazardous waste regulations (TGIC is classified as toxic aquatic substance; consult WHMIS SDS).