Fibre Sourcing
Secondary pulp material derived from post-consumer cartons or industrial paper waste constitutes recycled fibre within the packaging supply chain. Mills integrate this recovered furnish into corrugated medium and folding boxboard to reduce virgin wood consumption while meeting mandatory sustainability targets. Procurement specifications separate pre-consumer trim losses from post-consumer old corrugated containers because each category delivers distinct residual lignin content and hemicellulose degradation rates.
Converting plants monitor the resulting tear resistance and ring crush performance to verify that secondary pulp substitution does not compromise stacking strength on high-speed filling lines.
Refining Control
Mechanical beating restores hydration and surface area to recycled fibre before the stock reaches the paper machine headbox. Secondary pulp arrives with shortened and partially collapsed cellular structures that demand modified disc refiner settings to rebuild inter-fiber bonding without destroying drainage rates. Operators adjust specific edge load parameters to limit excessive fines generation that would otherwise choke wire mesh dewatering sections.
Tensile strength and burst index recover through this targeted treatment, allowing lightweight linerboard to maintain structural integrity under high humidity storage conditions.
Chain Custody
Independent auditing verifies the exact percentage of recycled fibre claimed on commercial delivery dockets and environmental product declarations. Certification bodies trace secondary pulp shipments from material recovery facilities through pulping plants to ensure strict mass balance accounting without physical commingling. Converters rely on these audited declarations to calculate the carbon footprint of finished folding cartons and corrugated shipping containers.
Regulatory compliance demands transparent documentation regarding origin and processing yields, separating verifiable post-consumer inputs from internal mill broke recycling.
