# Polycarbonate

Specify PC by grade, form and surface treatment; interpret impact, optical, thermal and chemical data within their test and application limits.

Reviewed: 2026-11-01

Tags: materials, polymers, polycarbonate, pc, glazing

## Identify the product and its function

Covestro **Makrolon 2805** lists **75 kJ/m² notched Charpy at 23°C** versus **16 kJ/m² at −30°C**, both for **3 mm** specimens on its **ISO 21305 / ISO 179/1eA-based** test. Verify low-temperature impact on the actual grade, thickness and geometry before qualifying a guard. [Covestro Makrolon 2805 properties](https://solutions.covestro.com/en/products/makrolon/makrolon-2805_000000000057534382)

**Polycarbonate**, abbreviated **PC**, is used in molding resins, stock shapes and sheet products with different formulations and surfaces. Covestro's **Makrolon® 2805** is a general-purpose injection-molding grade, while Exolon supplies general-purpose, UV, abrasion-resistant and other sheet variants. A shared polymer name does not make those products interchangeable. [Covestro 2805](https://solutions.covestro.com/en/products/makrolon/makrolon-2805_000000000057534382), [Exolon sheet range](https://www.exolongroup.com/en/57/GP.htm)

## Molded-resin data: preserve the conditions

Covestro's **Makrolon 2805** page lists these typical values under its **23°C/50% RH mechanical** heading:

| Quantity | Value | Test condition/method |
| --- | --- | --- |
| Tensile modulus | 2400 MPa | 1 mm/min, ISO 527-1/-2 |
| Yield stress | 66 MPa | 50 mm/min, ISO 527-1/-2 |
| Tensile creep modulus | 1900 MPa | 1000 h, ISO 899-1 |
| Notched Charpy impact | 75 kJ/m² | 23°C, 3 mm; ISO 21305/based on ISO 179/1eA |
| Notched Charpy impact | 16 kJ/m² | −30°C, 3 mm; same method basis |

Keep temperature, notch, thickness and method attached. A notched-bar value is not a glazing panel's impact-energy rating. [Covestro property table](https://solutions.covestro.com/en/products/makrolon/makrolon-2805_000000000057534382)

For an impact-critical assembly, qualify the relevant geometry, supports, fasteners, impactor, speed, temperature and acceptance criterion. Evaluate aging and chemical exposure where they affect service. Do not use “unbreakable” or a comparative marketing claim as a substitute for testing or an applicable assembly standard.

Short-term modulus and creep modulus answer different questions. For a loaded cover or clamped feature, define duration, temperature, permissible deflection and retained force. A room-temperature tensile number cannot establish long-term preload or resistance to every repeated impact.

## Stock shapes are a separate property record

Ensinger's **TECANAT natural** sheet lists **69 MPa tensile strength at 50 mm/min** and **2200 MPa tensile modulus at 1 mm/min**, by DIN EN ISO 527-2 with type-1b specimens. It generally uses extruded, machined reference specimens and labels its values as comparison guidelines rather than guaranteed specification limits. [Ensinger stock-shape data](https://www.ensinger-online.com/modules/public/sheet/createsheet.php?FILENAME=TECANAT_natural_0.PDF&FL=0&SID=1346&ZOOM=1.2)

Do not average these entries with a molding-resin table. Confirm relevant moisture/conditioning, orientation and test basis when the project requires details absent from a sheet. Define incoming-stock acceptance separately from final machining, dimensional and optical acceptance.

Ensinger gives longitudinal CLTE **8 × 10⁻⁵/K over 23–60°C**. As original preliminary arithmetic, a **100 mm free length** heated uniformly across that interval expands by `100 × 8 × 10⁻⁵ × 37 = 0.296 mm`. This excludes restraint, gradients and property variation. It is not a mounting-clearance or thermal-stress calculation. [Ensinger thermal-expansion interval](https://www.ensinger-online.com/modules/public/sheet/createsheet.php?FILENAME=TECANAT_natural_0.PDF&FL=0&SID=1346&ZOOM=1.2)

For a mounted panel, establish expansion allowance, hole geometry, support and clamp loads using the actual product and temperature range. Avoid constraining the part on the assumption that a fit measured at one temperature remains unchanged.

## Thermal tests and processing are not service guarantees

Covestro lists **145°C glass transition at 10°C/min**, but HDT is **125°C at 1.80 MPa** and **137°C at 0.45 MPa**. These distinct tests are not continuous loaded-part operating ratings. [Covestro thermal-test table](https://solutions.covestro.com/en/products/makrolon/makrolon-2805_000000000057534382)

Define actual temperature/time history and allowable mechanical, dimensional and optical changes. For molding or forming, use the current selected grade's preparation and processing instructions. For machining, qualify workholding, tool condition, heat input and any recommended intermediate treatment. Inspect after the required stabilization and conditioning.

Exolon's GP page describes thermoforming and cold bending. Its **AR 8099** is hardcoated on both sides, **AR 7099** on one side, and **AR FO** is a separately identified formable hardcoated product. Do not transfer a forming method between those variants without the applicable procedure. [Exolon GP](https://www.exolongroup.com/en/57/GP.htm), [Exolon AR product distinctions](https://www.exolongroup.com/en/59/AR.htm)

For coatings, retain the treated face, edge condition, printing/lamination requirements and cleaning procedure. Qualify optical quality after fabrication rather than assuming a transparent starting sheet guarantees the finished view.

## Chemical exposure and cleaning

Ensinger specifically flags **stress-cracking sensitivity** for TECANAT and poor resistance to hot water/bases. Treat chemical resistance as a loaded-service question, not merely whether an unstressed coupon visibly dissolves. [Ensinger compatibility flags](https://www.ensinger-online.com/modules/public/sheet/createsheet.php?FILENAME=TECANAT_natural_0.PDF&FL=0&SID=1346&ZOOM=1.2)

Specify cleaners, disinfectants, coolants, adhesives and sealants by formulation, concentration, temperature and exposure time. Include residual and assembly stress and repeated cleaning. Obtain compatibility guidance for the exact coated or uncoated product; a procedure suitable for one surface treatment may not suit another. Inspect representative parts for cracking, clouding and loss of function after exposure.

Define joining, inserts and fasteners as separate processes with their own preparation and acceptance. Bulk resin strength cannot establish bonded-joint capacity, screw preload retention or leak tightness. Reassess local stresses and chemical compatibility when the assembly process changes.

## Approvals, release and source dates

Exolon's **opaque GP B** sheet warns that fire certificates are limited by time and scope and that listed behavior concerns new, unweathered product. Do not transfer its classifications to transparent GP, another thickness or an aged assembly. [Exolon GP B, October 2025](https://www.exolongroup.com/index.php/fuseaction/download/lrn_file/mf0381_e_251017.pdf)

Require current product-specific documentation for glazing, machine guarding, electrical, fire or food-contact requirements. Retain grade, lot, form, thickness/coating, process and drawing revision, conditioning and final inspection. Review substitutions against the complete functional requirement.

Sources reviewed November 1, 2026. Ensinger's cited PDF prints **2023/07/19, Version AF**. Exolon GP B prints **Product data sheet, October 2025**; GP and AR web pages show **last updated 27.10.2026**. Covestro's cited product page gives no explicit technical revision date. Search-result and upload dates are not substituted for printed source dates.

## Related reference

[Material selection through production](../grades-tempers-and-conditions.md)