PCR Plastic Integration in Construction Chemicals

Overview

As part of Saint-Gobain / Fosroc's global carbon footprint and circular economy commitments, this initiative centered on replacing virgin high-density polyethylene (HDPE) with Post-Consumer Recycled (PCR) resins in rigid containers across heavy construction chemical product lines.

Construction chemicals represent a demanding packaging application due to product aggressiveness, elevated specific gravity, and the requirement for robust stacking strength during transit.

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Technical Challenge & Objectives

Integrating PCR into blow-moulded jerrycans and bottles introduces significant technical trade-offs that must be systematically engineered:

• Environmental Stress Crack Resistance (ESCR): PCR resins frequently exhibit variability in melt flow index (MFI) and molecular weight distribution, increasing susceptibility to stress cracking when in contact with active surfactants or plasticizers.
• Drop & Impact Performance: Chemical containers must pass rigorous drop tests (1.8m ambient and conditioned) without wall rupture or seam fracture.
• Extrusion Blow Moulding (EBM) Processability: Ensuring parison stability and uniform wall thickness distribution across multi-cavity machines.

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Engineering Methodology

1. Resin Sourcing & Characterization

• Evaluated high-purity recycled HDPE pellet grades from verified mechanical recycling partners.
• Conducted MFI profiling, ash content analysis, and FTIR spectroscopy to screen for contaminants and optimize compounding ratios.

2. Multi-Layer Co-Extrusion vs. Monolayer Blends

• Explored 3-layer co-extrusion architectures (virgin outer / PCR core / virgin inner) to prevent direct contact of recycled polymer with sensitive chemical formulas while maximizing overall PCR percentage.
• Engineered 20% to 30% blend formulations validated on pilot blow-moulding tooling.

3. Rigorous Prototype Validation

• ESCR Testing (ASTM D1693 / IS 8747): Full-bottle holding trials at 50°C accelerated environmental conditions.
• Drop & Hydraulic Pressure Testing: Drop tests from 1.8 meters across multiple drop angles (bottom chime, corner, flat face).
• Stacking Load Trials: 28-day continuous dead-weight compression testing under 40°C warehouse ambient temperatures.

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Key Results & Impact

• Zero Leakage Failures: Achieved complete qualification across accelerated storage and dynamic vibration simulation without container failure.
• Circularity Milestone: Successfully deployed PCR in primary packaging, significantly lowering reliance on virgin petrochemicals.
• 10+ Project Commercialisations: Scaled the sustainable packaging roadmap across multiple construction chemical SKUs from bench concept to factory-floor commercial runs.