PET
Specify polyethylene terephthalate by grade, crystallinity and manufactured form; interpret engineering stock-shape data, thermal limits and wet-service compatibility in context.
Tags: materials, polymers, pet, polyester, engineering-plastics
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Define the product and its structure
Ensinger TECAPET white gives longitudinal expansion of 8 × 10⁻⁵/K over 23–60°C. An assumed 100 mm free length heated uniformly across that interval expands 0.296 mm. Account for restraint, gradients, moisture and mating material when setting assembly clearance. Ensinger TECAPET white stock-shape data
PET is polyethylene terephthalate, a thermoplastic polyester. In engineering stock shapes, MCG's Ertalyte™ PET-P is an unreinforced, semi-crystalline grade offered as rod, plate and tubular bar. This is a specific product rather than a property definition for all PET packaging, film, molding resin or recycled feedstock. MCG Ertalyte product scope
Named stock-shape example: TECAPET white
Ensinger's TECAPET white sheet publishes:
| Quantity | Value and test condition |
|---|---|
| Density | 1.36 g/cm³, as listed |
| Tensile strength | 79 MPa, 50 mm/min, DIN EN ISO 527-2 |
| Tensile modulus | 3100 MPa, 1 mm/min, DIN EN ISO 527-2 |
| Yield strain | 5%, 50 mm/min, DIN EN ISO 527-2 |
| Longitudinal CLTE | 8 × 10⁻⁵/K, 23–60°C |
The sheet uses type-1b tensile specimens and generally extruded, machined reference specimens. Its values are selection guidelines, not guaranteed specification limits. Ensinger TECAPET sheet
Different supplier tables are different records
MCG's current Ertalyte sheet identifies comparison data for dry material and mechanical tests generally performed at 23°C on machined stock-shape specimens. It cautions that the values are not guaranteed and should not alone establish design or specification limits. Do not silently combine selected entries from it and Ensinger into a synthetic “best PET” table. MCG test scope and disclaimer
For procurement, agree required certificates, product dimensions, tolerances, surface condition and any lot-specific testing. For a machined component, define incoming-stock acceptance separately from final dimensional and functional acceptance. Material identity remains necessary even when two products have similar nominal density or strength.
Dimensional stability and fabrication
MCG's machining discussion identifies stiffness, residual stress and thermal expansion as contributors to machining stability, and states that its Ertalyte shapes undergo a proprietary annealing cycle. That product-specific manufacturing control does not guarantee that every finished geometry remains within tolerance after any machining sequence. MCG machining-stability discussion
Plan material removal, workholding, tool access and heat control for the actual blank. Inspect critical features after the specified stabilization and conditioning. Define where dimensional measurements are made and at what temperature. For heavy or asymmetric material removal, qualify a representative first part before assuming a stock-shape tolerance transfers to the finished component.
For molding or thermoforming, obtain the selected grade's current processing procedure, including feedstock preparation and the required thermal history. Do not use the stock-shape table as a processing recipe. Confirm how the resulting structure and orientation affect dimensions and function. Reassess substitutions when the supplied form or route changes.
Thermal limits and sustained loads
MCG lists 245°C melting temperature by DSC at 10°C/min, 80°C ISO HDT at 1.8 MPa, and 100°C continuous service in air for Ertalyte. Its service-temperature note uses at least 20,000 hours and roughly 50% loss of tensile strength measured at 23°C, while warning that mechanical stress and duration can govern. These are distinct test and aging quantities, not one operating rating. MCG thermal table and note 3
Define actual temperature, load duration, allowable creep, deflection and retained force. Include startup, cleaning, shutdown and thermal cycling. A loaded support, snap feature and freely expanding spacer can reach different limits even when made from the same grade. Obtain applicable long-term data or test representative parts rather than deriving service life from melting temperature.
For a bearing or wear guide, specify the counterface, finish, pressure, speed, lubrication, contamination and heat removal. A low-friction description is not a universal friction coefficient or dry-running allowance. Qualify the relevant material pair and duty, including dimensional changes that affect clearance or contact pressure.
Water, chemicals and application approvals
Ensinger marks poor resistance to hot water/bases for the cited TECAPET product. Its 0.02/0.03% water absorption after 24/96 hours at 23°C, measured on the stated specimen, does not establish unlimited hot-wet service or zero dimensional change. Ensinger absorption conditions and compatibility entries
Specify the actual chemical formulation, concentration, temperature, stress and contact time. Include cleaning and sanitation cycles instead of evaluating only normal operation. Confirm compatibility for the exact grade and representative completed part where performance is consequential. A general chemical-resistance description cannot authorize every detergent, acid or solvent mixture.
MCG notes that approvals can differ by color within its Ertalyte offering. Require current documentation for the actual grade, color, form and intended use. An industry application example does not establish blanket food, medical or electrical approval. MCG application/testing notes
Define joining and assembly separately, including preparation, inserts, fastener loads and inspection. Bulk tensile data cannot establish a bond's capacity, a thread's retained preload or a seal's leakage performance.
Release record and source dates
Retain grade, supplier/lot, form, process and drawing revisions, conditioning and required dimensional/functional results. Review substitutions against all service and manufacturing requirements.
Sources reviewed November 1, 2026. The retrieved Ertalyte PDF prints Date of issue: 20/10/2026. Ensinger's cited regional sheet prints 2023/07/19, Version AE, despite its filename containing 202603. MCG's product and machining web pages provide no explicit technical revision date; website copyright and search-result dates are not used as revisions.