In routine food-contact compliance practice, a downstream converter may transmit a request titled “A Client Wants a PET Food-Contact Statement Overnight: What You Can Sign” when shipment is already staged and a certificate is missing. The defensible same-day response must separate virgin resin compositional conformity from finished-article migration compliance. A signatory can sign only statements that trace directly to existing supplier certifications, positive-list entries, and previously executed test reports. No signature creates missing experimental data.

Polyethylene terephthalate is a linear aromatic polyester with a density near 1.38–1.40 g/cm³, a glass transition temperature near 75–80 °C, and a crystalline melting range commonly reported from 245 °C to 265 °C. These physical values establish material identity, not legal food-contact status. The controlling boundary is whether the specific formulation, additive package, processing history, and recycled-content position remain within the applicable positive lists and migration limits.

Does 21 CFR 177.1630 Cover the Full Formulation or Only the Base Polyester Backbone?

In the United States, 21 CFR 177.1630 describes PET as the polymerization product of terephthalic acid, dimethyl terephthalate, or terephthaloyl chloride with ethylene glycol. It also includes infrared identification specifications and extractives limitations. The section does not independently authorize every catalyst, colorant, nucleating agent, reheat additive, or oxygen scavenger present in a commercial bottle resin. Therefore a same-day letter can state that the base polymer is covered by 21 CFR 177.1630 only when the supplier certificate names that section and the formulation contains no non-cleared adjuvants. The statement “the resin is FDA food-contact safe” should not be signed because FDA clearance is substance-specific and condition-of-use-specific.

Adjuvants require their own clearances, often through 21 CFR 174.5 or a separate food-contact notification. If the supplier certificate lists a colorant or stabilizer without a CAS registry number and regulatory citation, the documented chain is incomplete. The overnight signatory must either obtain the missing data or reduce the document to plain resin identity. DMT-based PET receives the same base regulation, but finished-article conditions of use must still fall within the cleared scope.

FDA regulations do not use the phrase “food-contact statement” as a legal category. The signatory should understand the operative language: “conforms to 21 CFR 177.1630” or “acceptable for food contact under listed conditions of use.” A statement that omits conditions of use is unreliable because PET may be used in single-use bottles, heat-set hot-fill containers, films, or ovenable trays; each condition has different migration implications.

A production-scale preform line introduces variables that can shift article-level migration behavior even when the incoming resin is properly listed. On a 48-cavity hot-runner injection molder operating above 3,000 kN clamp force, PET is dried to residual moisture below 50 ppm at 160 °C in a desiccant bed system with a dew point no higher than -40 °C. Melt temperatures are normally held between 260 °C and 290 °C; exceeding 290 °C or extending residence time beyond 5 min elevates residual acetaldehyde and can increase low-molecular-weight oligomers. Residual acetaldehyde is measured by headspace gas chromatography under ASTM F2013. A statement based solely on incoming resin IV ignores this process history.

Intrinsic viscosity by ASTM D4603 for bottle-grade PET typically falls between 0.75 dL/g and 0.85 dL/g; film-grade material may fall between 0.58 dL/g and 0.68 dL/g. A process-induced drop of 0.05 dL/g or more indicates hydrolytic chain scission and an increase in extractable oligomers. A heat-set blow-molded container declaration therefore requires the processed material’s IV and residual monomer data, not only the resin manufacturer’s certificate.

Solid-state polymerization raises bottle-grade IV from approximately 0.60 dL/g to 0.82 dL/g under vacuum or nitrogen at 205–225 °C. Differential scanning calorimetry per ASTM D3418 shows crystallinity changes that affect diffusion-limited migration. A statement tied to a specific preform crystallinity is reliable only when the DSC thermogram and IV value are included in the supporting file.

Checking Process-Derived Migrants and Residual Monomer Against Standard Limits

Under EU 10/2011, Annex I Table 1 lists ethylene glycol with a specific migration limit of 30 mg/kg expressed as SML(T), and terephthalic acid with a specific migration limit of 7.5 mg/kg. Overall migration for plastic food-contact materials is limited to 10 mg/dm² under Article 12, or 60 mg/kg for food contact materials intended for infants and young children. A same-day statement invoking these limits must trace to a valid test report under EN 1186-1 or a substantiated migration calculation. Without such data, the signatory shall not declare compliance with overall migration or specific migration limits.

Unlike Annex I monomers, additives are controlled under EU 10/2011 Annex II. A resin certificate that lists an antioxidant or acetaldehyde scavenger must provide the Annex II reference. If the supplier certificate does not disclose the additive registry and authorization, the signatory must exclude that formulation from a same-day letter or obtain the certificate first. Cobalt-based reheat agents, antimony-trioxide catalysts, and toning agents require their own entries; they are not granted by 21 CFR 177.1630 or EU 10/2011 Annex I alone.

Residual monomer and acetaldehyde values are not direct food-contact clearance endpoints but influence sensory and oligomer profiles. Headspace GC under ASTM F2013 is used for residual acetaldehyde, with quantification limits near 0.5 µg/g typical in contract laboratories. When the request asks for water-contact suitability, the signatory can rely on compositional conformance only if the container has no non-authorized external coating and processing has not exceeded thermal degradation thresholds. A statement of sensory non-detectability should not be issued without sensory panel evidence.

Cyclic oligomers, primarily the cyclic trimer, migrate at low concentrations from PET. Published overall migration data for unfilled PET bottles under EN 1186-1 are often below 10 mg/dm²; however, a same-day statement concerning non-intentionally added substances cannot be signed unless a risk assessment under EU 10/2011 Article 19 already exists. NIAS are not automatically authorized by the base-polymer listing and must be excluded from same-day letters when no study is available.

When the Request Includes a Global Migration Statement Without an Existing Test Report

A request for global migration compliance under EU 10/2011 cannot be signed overnight if the only document on file is a resin supplier’s positive-list certificate. Overall migration testing requires the finished article to be exposed to the appropriate food simulant assigned in Annex III under the time–temperature conditions of Annex V. Protocols may require contact for up to 10 days at 40 °C, making overnight generation of new data impossible. The signatory may state that the article is composed of authorized materials, but not that overall migration limits are satisfied.

EU 10/2011 Article 15 requires a written declaration of compliance at non-retail stages, and Article 16 requires supporting documentation to be available for enforcement authorities. The same-day declaration can be produced only when the documentation chain—resin certificates, additive clearances, processing records, and any migration reports—already exists. If a laboratory test report is absent, the letter must be limited to positive-list conformity.

The same limitation applies to specific migration of ethylene glycol and terephthalic acid. Calculation from residual monomer content may be possible if confirmed by polymer analysis, but migration modeling requires diffusion coefficients, partition coefficients, and article thickness. PET diffusion coefficients are low, yet crystallinity, orientation, and contact duration alter migration. A same-day letter should not imply compliance with SMLs unless the calculation follows EU 10/2011 Article 18 or the test report is on file.

A raw-material Safety Data Sheet does not provide food-contact compliance. The same-day signatory cannot rely on an SDS alone, because OSHA hazard classification and REACH hazard information do not equal FDA or EU food-contact authorization. The signatory must obtain the supplier’s food-contact statement with regulatory references and formulation disclosure adequate to confirm positive-list status. A batch-specific traceability record is also required under EU 10/2011 Article 17 for European shipments. When batch identities are absent, a signed declaration is not supportable.

Evidence Matrix for Same-Day Food-Contact Declarations

The following matrix defines which statements can be signed when a converter needs an overnight PET food-contact position. “Signable” means a technical or regulatory signatory has sufficient existing documentation; it does not imply that missing test data can be replaced by language.

The matrix excludes statements concerning NIAS, sensory performance, and “FDA-approved” language, because those require additional data or are not valid regulatory phrases.

Recycled PET complicates the overnight signature in ways that virgin resin does not. Regulation (EU) 2022/1616 establishes decontamination process requirements for post-consumer PET; a valid authorization or EFSA opinion is a prerequisite for food-contact use. In the United States, FDA letters of no objection for recyclers are process-specific. A converter holding a virgin PET statement cannot extend it to post-consumer recycled content unless the recycled stream has the required authorization. High-quality bales processed with near-infrared sorters may reduce polyolefin contamination below 50 ppm, but that value must be verified per lot. A safe same-day document is therefore limited to virgin PET compositional conformity, with explicit exclusion of recycled-content claims when no letter or authorization exists.