Recycled terephthalic acid (rTFA) serves as a monomer obtained from chemical recycling of polyethylene terephthalate (PET). Manufacturers require clear quality standards to ensure that rTFA performs comparably to virgin terephthalic acid, especially where applications demand high purity.
Regulatory regimes adjusting standards for recycled plastics impose stricter criteria on monomer quality, contaminant levels, and traceability. This blog presents essential quality parameters for rTFA, reviews recent regulatory initiatives, assesses technological approaches to achieving required purity, and profiles manufacturers advancing high-quality rTFA production.
The global recycled terephthalic acid (rTFA) market was valued at USD 2,289.2 million in 2023 and is expected to rise from USD 2,379.7 million in 2024 to USD 3,214.7 million by 2031, reflecting a CAGR of 4.39% over the forecast period. This steady growth is fueled by the rising adoption of sustainable practices and circular economy initiatives across the plastics and textile industries.
Key Quality Parameters for rTFA
Purity and Chemical Composition
Purity in rTFA refers to the absence of impurities that can interfere with polymerization or degrade final product performance. Manufacturers must monitor residual acetaldehyde, dimethyl terephthalate, oligomers, heavy metals, and color bodies. Effective chemical recycling routes such as hydrolysis or methanolysis, must deliver monomers with purity above 99.5 percent in terms of terephthalic acid content for high-performance polyester or food-contact resins.
Moisture and Volatile Matter Content
Moisture severely affects polymerization reactions. Moisture content in rTFA must remain below critical thresholds, typically under 0.2 percent by weight, to prevent hydrolytic degradation during PET synthesis. Volatile organic compounds and low-boiling by-products must also be controlled to avoid off-gas and thermal stability issues.
Color, Clarity, and Description
Color index and clarity impact visual appearance and may indicate the presence of chromophoric impurities. Manufacturers must specify color metrics, using yellowness index, haze, and spectrophotometric transmittance. rTFA, intended for clear or light-colored PET bottles or films, demands minimal coloration so that it does not require heavy downstream bleaching or treatment.
Heavy Metals and Contamination Control
Heavy metals such as lead, cadmium, mercury, and chromium must remain under regulated limits. Food contact regulations in many jurisdictions require non-detectable or very low ppm (parts per million) levels. Contamination from dyes, label adhesives, or other feedstocks must be prevented via feedstock control, pretreatment, and efficient purification.
Traceability and Chain of Custody
Traceability ensures that the origin of feedstock (post-consumer, post-industrial PET waste) is known and documented. Chain of custody systems certify that rTFA is derived through compliant recycling processes. Manufacturers should maintain records of recycling process parameters (temperature, catalysts, and reaction time), monomer yields, batch testing, and quality certification. This enables compliance audits and regulatory approvals.
Regulatory and Standards Frameworks Influencing rTFA Quality
China’s New Recycled Plastics Standards
China’s State Administration for Market Regulation has issued new national standards for recycled plastics, to take effect on 1 February 2026. These standards require technical specifications for recycled materials, including test methods and quality parameters. Manufacturers aiming to supply rTFA-based materials into Chinese markets must ensure compliance with those standards. The standard setting will involve the China Petroleum and Chemical Industry Federation.
Food Contact and Safety Regulations in Other Jurisdictions
Governmental authorities in various countries are modifying rules to permit the use of recycled plastic materials in food contact under strict conditions. For example, India’s Food Safety and Standards Authority (FSSAI) amended regulations in March 2025 to allow recycled PET in food contact materials provided that the materials comply with notified standards and guidelines. That implies that rTFA derived PET must meet or exceed purity, residual chemicals, and migration test requirements. Official source: SGS commentary on FSSAI amendment.
Voluntary Standards and Industry Initiatives
Companies producing rTFA are collaborating on pilot projects to demonstrate parity of rTFA with virgin PTA in performance metrics. A recent collaboration between Selenis and Circ sought to confirm that recovered terephthalic acid from blended textile waste performs similarly to virgin monomers in the synthesis of rPET. Quality testing included evaluation of mechanical, optical, and chemical purity metrics. Official source: Selenis press release. (Source: www.selenis.com)
Technological Routes and Their Effect on Quality
Hydrolysis, Methanolysis, and Other Depolymerisation Methods
Hydrolysis tends to produce high-purity rTFA because it converts PET back to its monomeric acid form without intermediate ester forms. Methanolysis yields dimethyl terephthalate, which needs to be converted to terephthalic acid; conversion steps must ensure removal of methanol residues, catalysts, and side products. Impurities and color bodies arise from degraded PET feedstock or contaminants; purification stages such as filtration, distillation, or crystallization become critical.
Feedstock Selection and Pretreatment
Quality of feedstock has a large impact on final rTFA quality. Feedstock must be segregated to avoid colored or pigmented PET, avoid non-PET plastics, adhesives, coatings, or additives that degrade in chemical recycling. Pretreatment methods such as washing, de-labeling, alkaline treatment, and removal of non-PET fractions improve purity. Trace metals from colored PET or contaminated inputs require aggressive removal protocols.
Purification Techniques
After depolymerisation, steps such as crystallization, filtration, activated carbon de-colorization, and ion exchange may be necessary to reach the required standards. Manufacturers that target food-grade rTFA or high-clarity applications invest in multi-step purification protocols. Analytical testing (e.g., HPLC, GC-MS) must validate residual monomers, oligomers, catalyst residues, and volatile impurities. Routine batch-wise testing is essential for maintaining certification.
Quality Audits, Certifications, and Documentation
Manufacturers must adopt quality management systems conforming to widely recognized standards such as ISO 9001. Food contact applications require additional certifications or letters of no objection (NOL) from regulatory agencies. Batch documentation should include chemical analysis certificates, traceability of feedstock, details of process conditions, and evidence that the product meets or exceeds specified impurity thresholds.
Suppliers supplying to regulated markets should periodically undergo third-party audits. These audits should verify that manufacturing processes, purification steps, testing labs, and storage of rTFA maintain integrity. Manufacturers should retain data on color indices, heavy metals, moisture, residual catalysts, oligomer content, and monomer purity. Internal quality control and external validation reinforce trust among downstream users.
Manufacturers leading in rTFA Quality
Selenis and Circ offer demonstrable case studies in high-quality rTFA. Selenis uses recovered terephthalic acid from Circ and bio-monoethylene glycol from second-generation bio-based sources to produce rPET using rTFA. That undertaking established pilot trials evidencing parity of recovered monomer performance versus virgin materials in critical applications.
Other producers such as Indorama Ventures, Alpek, Far Eastern New Century, SK chemicals, and Loop Industries are investing in chemical recycling and higher purity rTFA processes. They are actively investing in high-barrier films, food contact grade resins, or monoethylene terephthalate monomer streams.
Challenges in Meeting Quality Standards
Cost of advanced purification increases processing costs of rTFA relative to virgin PTA. Infrastructure for collecting, pre-processing, chemical recycling, and monitoring remains expensive. Regulatory verification (such as migration tests in food contact uses) demands robust analytical capabilities. Feedstock inconsistency colored PET, additives, and metal traces introduce variance, which purification must remedy. Some jurisdictions lack harmonized standards specifically addressing monomer purity for rTFA, leading to fragmentation and uncertainty among manufacturers.
Recommendations for Manufacturers
Manufacturers aiming to produce rTFA that meets high-quality standards should adopt rigorous feedstock control, advanced purification, detailed analytical testing, and transparent documentation. Investment in pilot trials that demonstrate equivalence of performance metrics (mechanical, optical, and chemical) is essential. Engaging with regulatory bodies early ensure that the product specification aligns with food contact or high-performance use requirements. Participation in standardization efforts provides a chance to influence the criteria to be practical and science-based.
Conclusion
Recycled terephthalic acid quality standards constitute a critical factor for manufacturers targeting high-performance or regulated applications. Purity, contaminant control, color and optical clarity, traceability, and documented compliance represent pillars of acceptable rTFA quality. Regulatory changes in jurisdictions such as China and India enforce stricter requirements for recycled plastics, particularly for food contact uses or clarity sensitive applications. Manufacturers who invest in precise depolymerisation routes, advanced purification, and robust quality management systems will obtain competitive advantage. Robust certification and alignment with emerging legal standards offer pathways for rTFA to replace virgin PTA in many sectors while upholding performance and safety.
