Factory Audit Report for PVC Foam Board Suppliers in Zhejiang & Shandong Provinces
Prepared for: Puerto Rico Importer
Date: July 25, 2025
Confidentiality Note: Factory details omitted per NDA terms.
1. PVC Foam Board Production Process & Raw Material Preparation
A. Production Workflow
- Raw Material Preparation
- PVC Resin: Sourced from Tier-1 suppliers (K-value 57–65 for optimal foaming).
- Foaming Agents (e.g., AC foamer): Pre-mixed with stabilizers (Ca/Zn or Pb-free for eco-grade).
- Additives: UV inhibitors, impact modifiers (e.g., CPE), and fire retardants (for construction-grade boards).
- Filler Masterbatch: Calcium carbonate (CaCO₃) tested for purity (≥96%) and particle size (≤2μm).
- Mixing & Extrusion
- High-speed mixing at 110–120°C to ensure homogeneity.
- Twin-screw extrusion with temperature zones: 160–190°C (foaming occurs at die head).
- Foaming & Calendering
- Free-foaming or Celuka (controlled skin) process for density adjustment (0.4–0.8 g/cm³).
- Surface embossing or gloss finishing via calendering rolls.
- Cooling & Cutting
- Water-cooling tunnels to stabilize dimensions.
- CNC cutting to tolerance ±0.5mm (ISO 2768).
B. Raw Material Grading
- Grade A: Virgin PVC, low-ash CaCO₃ (indoor applications).
- Grade B: Recycled PVC content ≤20% (outdoor non-structural).
- Flame-Retardant Grade: Added aluminum trihydrate (ATH) for ASTM E84 Class A.
2. Quality Control (QC) & Common Defects
A. QC Checkpoints
- Visual Inspection:
- Surface: Cracks, bubbles, or uneven gloss (≤3 defects/m²).
- Edges: Chipping or delamination (≤1mm tolerance).
- Dimensional Accuracy:
- Thickness: ±0.1mm (per ASTM D6287).
- Flatness: ≤0.5mm warp over 1m length.
- Physical Properties:
- Density: Measured via water displacement (target ±0.05 g/cm³).
- Peel strength: ≥4 N/mm (for laminated boards).
B. Frequent Defects
- Foaming Issues: Inconsistent cell structure (over/under-foaming).
- Contamination: Black spots from unclean extruders.
- Warping: Improper cooling or storage.
3. Laboratory Tests & Standards
| Test Item | Method | Requirement |
|---|---|---|
| Tensile Strength | ASTM D638 | ≥15 MPa |
| Impact Resistance | ASTM D256 (Izod) | No fracture at 5 kJ/m² |
| Fire Rating | UL94/EN 13501-1 | V-0 or B1 |
| Weathering Resistance | QUV Accelerated Aging | ΔE ≤3 after 1,000 hours |
| Formaldehyde Emission | CARB NAF/EPA TSCA | ≤0.05 ppm |
4. Factory Background & Compliance
- Market Focus: 60% export (Americas/EU), 40% domestic.
- Certifications: Verified ISO 9001, ISO 14001, and OEM agreements with EU distributors.
- Customer Vetting: Cross-checked via:
- B2B Platforms: Alibaba Gold Supplier status (5+ years).
- Bank References: Confirmed financial stability.
- Past Audit Reports: SOC 2 compliance for US-bound orders.
5. PVC Foam Board Classification
| Category | Material | Applications | Key Features |
|---|---|---|---|
| General Purpose | Virgin PVC + CaCO₃ | Signage, furniture | Lightweight, paint-friendly |
| Flame-Retardant | PVC + ATH | Public transport, HVAC ducts | UL94 V-0, self-extinguishing |
| Marine Grade | PVC + UV stabilizers | Boat interiors, pool areas | Saltwater-resistant |
| High-Impact | PVC + CPE modifiers | Construction formwork | 30% higher toughness |
Conclusion: Factories audited met the client’s technical and compliance criteria. Minor improvements recommended in foaming process consistency. Full report with scoring matrix shared via encrypted portal.
Prepared by: [Your Company Sourcing & QC Team]
Contact: [Generic Email/Ref. Code]
