Fibre Length Loss across Recycling Loops and Score Cracking
Recycled fibre shortening and hornification limit bending strain, requiring wider matrix channels and virgin top layers to prevent score cracking.
BS 7484
Paper Standard
British standard BS 7484 specifies the physical and chemical requirements for boards used in containers and cartons. Mills manufacture paper and folding boxboard to meet these exact caliper and bursting strength thresholds. Production lines maintain rigid control over basis weight and moisture content because small deviations alter final packaging performance during automated conversion.
Converting plants rely on defined tearing resistance values to prevent web breaks on high speed printing presses. Converters measure stiffness through bending moment calculations before cutting stock for corrugated packaging. Folding cartons demand precise creasing properties to ensure clean corner formation without cracking the outer liner.
Fibre composition limits dictate recycled content percentages alongside virgin pulp ratios to satisfy environmental purchasing policies. Mills verify compliance through standardized laboratory testing procedures under controlled atmospheric conditions. Testing laboratories measure tensile energy absorption values to predict drop resistance in finished shipping containers.
Regulatory bodies enforce these criteria across European supply chains to guarantee carton stacking strength during transit.
Surface Property
Smoothness parameters define ink absorption rates on coated cartonboard surfaces. Print shops evaluate gloss levels against established industry benchmarks to control ink trap during lithographic runs. Coating weight tolerances govern porosity measurements because excessive binder migration causes blistering in thermal drying tunnels.
Surface pH values determine chemical compatibility with specific laminating adhesives used in flexible packaging construction. Offset lithography requires strict control over Cobb water absorption values to prevent dampening solution transfer into the substrate. Laminating films adhere reliably only when surface tension exceeds thirty six dynes per centimetre after corona treatment.
Print finishing departments test rub resistance to ensure inks withstand subsequent die cutting operations without smudging.
Environmental Claim
Sustainability verification depends on documented chain of custody tracking from certified forestry operations to the final converter. Auditing bodies inspect mill effluent management systems alongside energy consumption metrics during annual compliance reviews. Recyclability assessments measure repulpability yields to confirm the absence of permanent wet strength resins in standard paper grades.
Carbon accounting protocols quantify greenhouse gas emissions associated with pulp drying and transport phases across the supply chain. Environmental declarations detail the proportion of post consumer waste integrated into each specific board grade. Brand owners substantiate green marketing statements using third party verified lifecycle analyses rather than internal estimates.
Regulatory authorities penalize false environmental assertions concerning packaging degradability.