ISBM materials / Material evaluation
PCTG Bottle Molding
PCTG bottle molding should be evaluated using the exact supplier grade and the intended bottle, not a PETG processing recipe copied under a different material name. The first task is to establish which molding route the supplier supports and what evidence is needed for the proposed ISBM configuration. Review viscosity information, thermal history, appearance requirements and sample dimensions together. A successful material review defines a testable proposal and clear acceptance conditions without claiming that an untested bottle is already production-ready.
What supplier information is needed first?
Request the full grade designation, current technical data sheet, safety data sheet and processing instructions for the intended method. Ask the supplier to confirm the material classification and relevant additives. Commercial copolyester names and abbreviated labels are not enough to identify an interchangeable formulation.
Eastman's DN004 documentation illustrates why grade-level records matter: it identifies a mold-release additive and reports typical properties under specified tests. Its published shrinkage entry is tied to a 3.2 mm specimen and a direction relative to flow. Such data describe that test and grade, not the dimensions of an arbitrary bottle. Read the DN004 technical data sheet.
Which variables belong in the PCTG review?
Viscosity information
Keep the method, temperature and shear conditions with any flow or viscosity value. Do not compare unlike measurements as if they were interchangeable. Ask which information supports the proposed preform and forming route.
Thermal history
Document drying, transfer, melt residence and any restart or reprocessing history. Use the selected grade's preparation guidance. A process record must show what happened to the actual lot used in the trial.
Appearance requirements
Define clarity, color, gloss and allowable visible defects for the final container. Test chemical exposure using the intended contents and conditions rather than interpreting a broad resin claim as finished-package approval.
Sample dimensions
Record specimen thickness, bottle drawing revision, neck finish, wall locations and test conditioning. A plaque result, a molded component and a stretched bottle are different specimens and should be labeled accordingly.
Why should PCTG not inherit a PETG recipe?
A material-family relationship does not establish the same processing window. Verify preparation instructions and the supported molding method for the actual grade, then review the machine and preform design. Treat settings from another copolyester as historical information, not authorized starting conditions.
The same distinction applies to results. A clear sample made from one grade does not prove the appearance, chemical resistance or dimensional behavior of another grade. When a supplier or formulation changes, identify which parts of the qualification remain applicable and which must be repeated. Preserve that decision with the project record.
How should bottle feasibility be tested?
Begin with an agreed bottle drawing and acceptance plan. Have the material supplier and equipment engineer review whether the proposed injection stretch-blowing route is appropriate. If the available documentation only covers another process, obtain the missing guidance before representing the grade as confirmed for ISBM.
Use traceable samples from the proposed material, preform and tooling combination. Evaluate the neck, overall dimensions, wall distribution and appearance using methods chosen for the bottle. Record the actual process revision and sample age or conditioning where these affect the measurement. A trial should answer a defined feasibility question, not simply demonstrate that a hollow shape can be formed.
Do not use this guide as a claim that PCTG is supported by every model. If a trial cannot meet the requirements, reconsider the grade, geometry or forming route with the supplier rather than concealing a limitation behind a general compatibility statement.
PCTG grade trial record
| Review item | Record to collect | Decision or acceptance basis |
|---|---|---|
| Supplier identity | Manufacturer, trade name, grade, lot and classification | Documents refer to the exact trial material |
| Supported process | Supplier guidance and engineering review | Proposed forming route is explicitly assessed |
| Viscosity basis | Reported value with method and test conditions | Only equivalent measurements are compared |
| Thermal history | Preparation and processing logs linked to sample IDs | Results traceable to actual material handling |
| Specimen definition | Drawing, thickness, dimensions and conditioning | Test result interpreted for the measured specimen |
| Appearance and use | Reference sample and application-specific tests | Finished container meets the agreed requirements |
| Disposition | Reviewer, evidence references and limitations | Approved scope or defined next trial |
This record is a framework for collecting real evidence. It contains no invented trial values, customer results or approval signatures.
Where does this page fit in the material decision?
This page focuses on PCTG grade identification and bottle feasibility. PETG has its own material review and should not be treated as a substitute formulation. Return to the ISBM materials overview to organize the broader material comparison.
Once the material and bottle requirements are defined, review the proposed injection stretch blow molding equipment. Procurement, mold interfaces and output commitments require their own project evidence; they cannot be derived from a resin data sheet alone.
Questions before the next step
Is a material name enough to approve a PCTG bottle project?
No. Obtain the supplier, exact grade, processing guidance and bottle requirements. The review must establish whether the intended method and configuration have supporting evidence.
Can a data-sheet shrinkage value be used as bottle shrinkage?
Not automatically. Check the specimen geometry, thickness, method and direction reported by the supplier, then measure the actual bottle under the agreed conditions.
What should happen when only PETG trial data are available?
Keep them as separate historical evidence. Obtain guidance for the proposed PCTG grade and define a new or justified partial trial plan; do not relabel the PETG results.
Technical references
Supplier information is grade-specific. Review the current documents for your proposed material; these references do not certify an ISBM machine or a finished bottle. Reference review date: November 9, 2026.
Discuss Your Bottle Project
Share the exact resin grade, bottle drawing or sample, capacity, weight, neck dimensions, bottle height and body diameter. Include required accepted output and your factory location and power supply.
Provide the material documents and available trial records so the proposed ISBM configuration can be reviewed against your actual requirements.