PVC FOAM BOARD Quality Checklist & Grading Rules
（Based on QB/T 5883-2023, QB/T 5884-2023, ISO & ASTM standards）
1. Basic Information
- Product Name: Rigid PVC Foam Board (Expanded PVC Sheet)
- Raw Material: Suspension-grade PVC resin + CaCO₃ + foaming agent + stabilizers + lubricants + impact modifiers
- Common Sizes:
- Thickness: 1mm–30mm
- Width: 1220mm / 1560mm / 2050mm
- Length: 2440mm / 3050mm / customized
- Density Range: 0.35–0.9 g/cm³（350–900 kg/m³）
2. Visual & Surface Quality Checklist
2.1 Surface Appearance
- ✅ Color: Uniform, no yellowing, no fading, no obvious color difference (ΔE ≤ 2.0)
- ✅ Surface finish: Smooth, matte, no flow marks, no gloss inconsistency
- ✅ Cleanliness: No dust, oil, scratches, dents, or contamination
- ✅ Pinholes & bubbles:
- Acceptable: Ø < 0.5mm, ≤10 pcs/m²
- Minor: Ø 0.5–1.0mm, ≤5 pcs/m²
- Reject: Ø > 1.0mm or through bubbles
- ✅ Cell structure: Uniform fine cells, no large voids (>2mm), no honeycomb defects
- ✅ Edges: Straight, clean, no burrs, no chipping, no cracking
2.2 Flatness & Warpage
- ✅ Flatness deviation: ≤ 2mm/m (Premium: ≤1mm/m)
- ✅ Warpage: ≤ 3mm/m (lengthwise & crosswise)
- ✅ No twisting, no cupping, no bowing
3. Dimensional Tolerance Checklist
3.1 Thickness
- Nominal ≤10mm: ±5% (Premium: ±3%)
- Nominal >10mm: ±10% (Premium: ±5%)
- Example: 15mm board → 13.5–16.5mm (Standard); 14.25–15.75mm (Premium)
3.2 Length & Width
- Tolerance: ±3mm (per 2440mm length)
- Squareness: Diagonal difference ≤ 2mm/m
3.3 Density
- Deviation: ±0.05 g/cm³ from specified value
- Uniformity: Max–min ≤ 0.03 g/cm³ across sheet
4. Physical & Mechanical Properties Checklist
（Test methods: ISO 1183, ISO 178, ASTM D2240, etc.）
表格
| Item | Standard Grade | Premium Grade | Test Method |
|---|---|---|---|
| Density | 0.35–0.9 g/cm³ | 0.4–0.8 g/cm³ | ISO 1183 |
| Flexural Strength | ≥12 MPa | ≥18 MPa | ISO 178 |
| Shore Hardness (D) | D 45–55 | D 50–60 | ASTM D2240 |
| Screw Holding Strength | ≥600 N | ≥800 N | QB/T 5883-2023 |
| Impact Strength (Izod) | ≥2.0 kJ/m² | ≥3.5 kJ/m² | ASTM D256 |
| Heat Distortion Temp. | ≥70°C | ≥75°C | ISO 75 |
| Linear Shrinkage (80°C) | ≤2.0% | ≤1.5% | QB/T 5883-2023 |
| Water Absorption | ≤1.0% | ≤0.5% | ISO 2896 |
| Closed Cell Rate | ≥90% | ≥95% | ISO 845 |
5. Defect Classification & Grading Rules
5.1 Grade Definition
- Grade A (Premium): No critical defects; minor defects within strict limits; meets all premium specs.
- Grade B (Standard): No critical defects; minor defects within standard limits; meets all standard specs.
- Grade C (Utility): No critical defects; minor defects exceed standard but within tolerance for non-critical use.
- Reject: Any critical defect or excessive minor defects.
5.2 Defect Severity
Critical (Reject Immediately)
- Through bubbles, cracks, or splits
- Severe warpage (>3mm/m) or twisting
- Thickness out of ±10% tolerance
- Large voids (>2mm) or honeycomb structure
- Surface contamination that cannot be cleaned
- Yellowing or color degradation (ΔE > 3.0)
Minor (Grade B/C)
- Pinholes: Ø 0.5–1.0mm, 5–10 pcs/m²
- Slight scratches (depth <0.1mm, length <50mm)
- Slight color difference (ΔE = 2.0–3.0)
- Flatness: 2–3mm/m
- Edge chipping (≤5mm, ≤2 per edge)
6. Sampling & Inspection Procedure
- Lot Size: ≤500 sheets → sample 5 sheets; >500 → sample 10 sheets.
- Visual Check: 100% surface inspection under 500–1000 lux light.
- Dimensional Check: Measure 3 points (edge, middle, edge) per sheet.
- Lab Test: 1 sample per lot for density, flexural strength, screw holding.
- Acceptance: If ≤1 defective sheet → accept; ≥2 → reject.
7. Application-Based Grade Recommendation
- Grade A: Printing, signage, furniture, cabinetry, marine, outdoor (UV-stabilized)
- Grade B: Interior decoration, partitions, display stands, packaging
- Grade C: Temporary structures, backer boards, non-visible components
8. Key Quality Control Tips
Store flat, covered, dry (avoid direct sunlight & moisture)
Use UV stabilizers to prevent yellowing (critical for outdoor use)
Control cell size (0.1–0.5mm) for uniform strength
Ensure surface skin integrity (no delamination) for printing & durability
