Guide de traitement du rPET : Norme ISBM relative au PET recyclé pour les emballages durables coréens

1. K-EPR Regulatory Landscape

The Korean Extended Producer Responsibility (K-EPR) framework, administered by the Ministry of Environment under Resource Recycling Act amendments announced in 2023, requires Korean beverage packaging producers to incorporate minimum recycled PET content on a phased timeline. Current requirements: 15% rPET content minimum for 2026 production year, 30% for 2027, 40% for 2028, and 50% target for 2030 and beyond. Non-compliance carries per-bottle financial penalty starting at 12 KRW per bottle for 2026 shortfall, rising to 45 KRW per bottle for 2030 shortfall. For a major bottler producing 3 billion bottles annually, a 10% rPET shortfall translates to 36 billion KRW (roughly 27 million USD) annual penalty exposure.

Beyond domestic K-EPR compliance, global brand owner sustainability commitments push rPET adoption at voluntary rates ahead of Korean mandatory thresholds. Coca-Cola Korea targets 50% rPET by 2025, Lotte Chilsung targets 30% rPET by 2026, and premium K-beauty brands increasingly specify 25-40% rPET for export product lines. Korean contract bottlers and cosmetic packaging producers who cannot deliver rPET processing capability face accelerating market access constraints regardless of K-EPR legal requirements.

rPET processing differs from virgin PET processing in five fundamental dimensions: intrinsic viscosity drop from recycling heat cycles, contaminant content including residual adhesives and colour migration from previous product cycles, processing temperature sensitivity requiring tighter melt temperature control, cycle-to-cycle property variation as feedstock quality fluctuates, and aesthetic colour drift toward yellow-grey tint after multiple recycling generations. Each dimension requires dedicated process adjustments that this guide addresses in detail.

2. rPET Grade Classification

Not all rPET is equivalent. Grade classification determines processability, application suitability, and regulatory compliance scope. Four Korean-market rPET grades cover 95% of commercial applications.

Korean bottlers primarily use Grades 1 and 2 for K-EPR compliance production. Grade 3 serves the non-food household and detergent packaging segment. Bottle-to-bottle (Grade 1) rPET supply in Korean market remains capacity-constrained at roughly 180,000 tons per year against projected 2027 demand of 320,000+ tons, creating supply pressure that favours bottlers with established rPET supplier relationships.

3. Intrinsic Viscosity Drop Compensation

Intrinsic viscosity (IV) measures the average molecular weight of PET. Virgin bottle-grade PET typically ships at 0.80-0.84 dL/g. Each recycling thermal cycle drops IV by 0.02-0.04 dL/g through chain scission during remelting. Without compensation, rPET bottles produced from 2-3 cycle recycled material show reduced top-load strength, clarity degradation at extreme stretch zones, and increased stress whitening susceptibility. For the underlying polymer science, see our guide d'orientation biaxiale.

IV compensation strategies:

• ✓Solid-state polymerisation (SSP): rPET flake heated to 200-220°C under vacuum for 8-12 hours, raising IV by 0.04-0.08 dL/g
• ✓Chain extender additives: 0.3-0.8% loading of pyromellitic dianhydride or similar additive restores 0.03-0.06 dL/g IV
• ✓Virgin PET dilution: blending 30-50% virgin PET with rPET raises effective IV proportionally; standard approach for K-EPR compliance
• ✓Preform geometry adjustment: 3-5% thicker preform wall compensates for lower rPET IV without property penalty
• ✓Processing temperature reduction: melt temperature 5-10°C lower than virgin reduces additional IV degradation during ISBM processing

4. Contaminant Tolerance & Management

rPET feedstock carries contamination risk that virgin PET does not: residual label adhesive, cap fragment PE/PP carryover, dye migration from coloured bottle mix, and trace contaminants from previous beverage contents. Food-grade bottle-to-bottle rPET passes through super-clean decontamination that removes 99.95%+ of these contaminants, but Grade 2 standard rPET retains detectable residues that affect processing.

In-line melt filtration at 40-80 micron mesh catches particulate contamination during ISBM injection. Melt filter pressure drop monitoring flags contamination above normal thresholds; sudden pressure rise indicates filter clogging from contaminated lot and triggers QC hold before production damage accumulates. Korean bottlers running sustained rPET production typically replace melt filters 2-3× more frequently than virgin production lines.

5. ISBM Process Window Adjustments

rPET processing shifts ISBM process windows in predictable directions. Understanding these shifts upfront saves days of trial-and-error during rPET commissioning on a previously virgin-only production line.

Process adjustments for 50% rPET blend vs 100% virgin reference:

• ▸Melt temperature: reduce 5-10°C (typically 272-282°C vs 278-288°C virgin) to minimize further IV degradation
• ▸Injection pressure: increase 5-12% to compensate for lower melt flow index of higher-molecular-weight rPET
• ▸Preform conditioning: 2-3°C lower temperature (98-107°C vs 100-110°C) for tighter stretch ratio control
• ▸Blow pressure: 1-2 bar higher main blow to compensate for slightly higher material flow resistance
• ▸Cooling time: extend 5-8% to ensure full thermal equilibration; rPET slightly slower to set than virgin
• ▸Drying: elevated moisture target < 30 ppm (vs < 50 ppm virgin) due to rPET higher moisture absorption tendency

6. Colour Drift & Aesthetic Management

rPET bottles develop yellow-grey tint that increases with recycled content percentage and number of recycling cycles. Standard virgin PET clocks at L*=96, a*=-0.5, b*=0.5 (CIE Lab colour space). 30% rPET typically measures b*=1.5-2.5 (yellow shift). 50% rPET measures b*=2.5-4.0. Pure 100% rPET beyond Grade 1 food-contact can reach b*=5-8 visible yellow tint.

Colour management approaches:

• ✓Blue toning masterbatch: 0.02-0.08% blue toner offsets yellow shift visually; restores perceptual clarity
• ✓Optical brightener: UV-fluorescence additive emits visible blue-white light, counteracting yellow
• ✓Brand reformulation to coloured bottles: some Korean brands reposition with green or amber tint that absorbs yellow drift naturally
• ✓Higher rPET grade specification: shift from Grade 2 to Grade 1 bottle-to-bottle reduces yellow shift by 50-70%
• ✓Consumer messaging: eco-brand positioning converts slight colour shift into sustainability authenticity signal

7. Virgin/rPET Blend Strategies

Blend percentage decisions balance K-EPR compliance requirement, cost optimisation, processing feasibility, and brand quality positioning. Four typical blend strategies dominate Korean production practice.

8. Machine Configuration Requirements

Standard ISBM platforms process rPET within normal operating envelope when properly configured. No fundamental machine redesign is required for K-EPR compliance production up to 50% rPET content. However, specific configuration optimisations improve yield and consistency on rPET-specific production.

rPET-optimised machine configuration:

• ▸Melt filter: 40-80 micron screen with pressure-drop monitoring; plan 2-3× more frequent replacement than virgin
• ▸Dryer capacity: sized for rPET moisture target < 30 ppm; approximately 15-20% larger than virgin-only requirement
• ▸Blender capacity: gravimetric blender capable of blending virgin, rPET, toning masterbatch, optional chain extender
• ▸PLC recipe library: separate rPET profile per blend percentage with temperature, pressure, cycle time adjustments
• ▸Cylinder wear protection: bimetallic-lined injection barrel extends service life 2-3× on sustained rPET production
• ▸Extended barrel vent: 2-stage vent zone for moisture and volatile extraction during rPET melting

Le Quai à 4 stations HGY150-V4 ships with standard rPET-compatible configuration. Ever-Power offers an rPET-optimised option package including bimetallic injection cylinder, extended barrel vent, and pre-programmed PLC recipes for 15%, 30%, 50%, and 100% rPET blends. Retrofit packages are available for existing HGY-series installations to enable K-EPR compliance production without full platform replacement.

9. Korean Bottler Case Studies

10. Conclusion

rPET processing transforms from optional sustainability initiative to mandatory K-EPR compliance requirement across Korean beverage and packaging production. The 30% by 2027 and 50% by 2030 thresholds require Korean bottlers to master intrinsic viscosity drop compensation, contaminant management, process window adjustments, colour drift mitigation, and blend strategy selection while maintaining production economics that sustain competitive unit cost. Korean bottlers who build rPET capability early gain regulatory compliance margin, brand sustainability positioning, and access to premium export channels where global brand owner sustainability commitments accelerate ahead of domestic regulatory timelines.

Ever-Power ISBM platforms support rPET processing across the full K-EPR compliance range with standard machine architecture plus optional rPET-optimisation package including bimetallic injection cylinder, extended barrel vent, and pre-programmed PLC recipes for typical blend percentages. Retrofit packages enable existing installations to add rPET capability without full platform replacement. Combined with gravimetric blender integration, in-line colour monitoring, and IV verification workflow, the configuration matches the production discipline Korean bottlers require to deliver K-EPR compliance without sacrificing quality or production economics.